Bài 28: Đọc và ghi dữ liệu nhị phân dùng luồng byte trong Java

[nguoihung96]

[color=#000000]
[/color][color=#007700][[/color][color=#0000bb]spoiler[/color][color=#007700]=[/color][color=#0000bb]spoiler[/color][color=#007700]][/[/color][color=#0000bb]spoiler[/color][color=#007700]][/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]datainputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]dataoutputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]fileinputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]fileoutputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]ioexception[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700];    class [/color][color=#0000bb]sinhvien [/color][color=#007700]{private [/color][color=#0000bb]string ten[/color][color=#007700];private [/color][color=#0000bb]int namsinh[/color][color=#007700];private [/color][color=#0000bb]float diemtb[/color][color=#007700];public [/color][color=#0000bb]string getten[/color][color=#007700]() {return [/color][color=#0000bb]ten[/color][color=#007700];}public [/color][color=#0000bb]void setten[/color][color=#007700]([/color][color=#0000bb]string ten[/color][color=#007700]) {[/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]ten [/color][color=#007700]= [/color][color=#0000bb]ten[/color][color=#007700];}public [/color][color=#0000bb]int getnamsinh[/color][color=#007700]() {return [/color][color=#0000bb]namsinh[/color][color=#007700];}public [/color][color=#0000bb]void setnamsinh[/color][color=#007700]([/color][color=#0000bb]int namsinh[/color][color=#007700]) {[/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]namsinh [/color][color=#007700]= [/color][color=#0000bb]namsinh[/color][color=#007700];}public [/color][color=#0000bb]float getdiemtb[/color][color=#007700]() {return [/color][color=#0000bb]diemtb[/color][color=#007700];}public [/color][color=#0000bb]void setdiemtb[/color][color=#007700]([/color][color=#0000bb]float diemtb[/color][color=#007700]) {[/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]diemtb [/color][color=#007700]= [/color][color=#0000bb]diemtb[/color][color=#007700];} public [/color][color=#0000bb]void ghithongtin[/color][color=#007700]() [/color][color=#0000bb]throws ioexception [/color][color=#007700]{[/color][color=#0000bb]dataoutputstream dataout[/color][color=#007700];try {[/color][color=#0000bb]dataout [/color][color=#007700]= new [/color][color=#0000bb]dataoutputstream[/color][color=#007700](new [/color][color=#0000bb]fileoutputstream[/color][color=#007700]([/color][color=#dd0000]"e:\\thongtin.dat"[/color][color=#007700]));} catch ([/color][color=#0000bb]exception e[/color][color=#007700]) {[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#0000bb]e[/color][color=#007700]);return;} try {[/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writeint[/color][color=#007700]([/color][color=#0000bb]getnamsinh[/color][color=#007700]());[/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writeutf[/color][color=#007700]([/color][color=#0000bb]getten[/color][color=#007700]());[/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writefloat[/color][color=#007700]([/color][color=#0000bb]getdiemtb[/color][color=#007700]());} catch([/color][color=#0000bb]exception e[/color][color=#007700]){[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#0000bb]e[/color][color=#007700]);} [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700](); }}    public class [/color][color=#0000bb]ghifilekieunhiphan [/color][color=#007700]{public static [/color][color=#0000bb]void [/color][color=#007700]try() [/color][color=#0000bb]throws ioexception[/color][color=#007700]{[/color][color=#0000bb]sinhvien sinhvien [/color][color=#007700]= new [/color][color=#0000bb]sinhvien[/color][color=#007700]();[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhap ten: "[/color][color=#007700]);@[/color][color=#0000bb]suppresswarnings[/color][color=#007700]([/color][color=#dd0000]"resource"[/color][color=#007700])[/color][color=#0000bb]scanner scan [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);[/color][color=#0000bb]sinhvien[/color][color=#007700].[/color][color=#0000bb]setten[/color][color=#007700]([/color][color=#0000bb]scan[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]());[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhap nam sinh: "[/color][color=#007700]);[/color][color=#0000bb]sinhvien[/color][color=#007700].[/color][color=#0000bb]setnamsinh[/color][color=#007700]([/color][color=#0000bb]scan[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]());[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhap diem trung binh"[/color][color=#007700]);[/color][color=#0000bb]sinhvien[/color][color=#007700].[/color][color=#0000bb]setdiemtb[/color][color=#007700]([/color][color=#0000bb]scan[/color][color=#007700].[/color][color=#0000bb]nextfloat[/color][color=#007700]()); [/color][color=#0000bb]sinhvien[/color][color=#007700].[/color][color=#0000bb]ghithongtin[/color][color=#007700]();} public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string[/color][color=#007700][] [/color][color=#0000bb]args[/color][color=#007700]) [/color][color=#0000bb]throws ioexception[/color][color=#007700]{[/color][color=#0000bb]datainputstream datain [/color][color=#007700]= [/color][color=#0000bb]null[/color][color=#007700];try {[/color][color=#0000bb]datain [/color][color=#007700]= new [/color][color=#0000bb]datainputstream[/color][color=#007700](new [/color][color=#0000bb]fileinputstream[/color][color=#007700]([/color][color=#dd0000]"e:\\thongtin.dat"[/color][color=#007700]));} catch ([/color][color=#0000bb]exception e[/color][color=#007700]) {[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#0000bb]e[/color][color=#007700]);try();} try {            [/color][color=#0000bb]int i [/color][color=#007700]= [/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readint[/color][color=#007700]();            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nam sinh " [/color][color=#007700]+ [/color][color=#0000bb]i[/color][color=#007700]);            [/color][color=#0000bb]string d [/color][color=#007700]= [/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readutf[/color][color=#007700]();            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"ten " [/color][color=#007700]+ [/color][color=#0000bb]d[/color][color=#007700]);            [/color][color=#0000bb]float diem [/color][color=#007700]= [/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readfloat[/color][color=#007700]();            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"diem tb " [/color][color=#007700]+ [/color][color=#0000bb]diem[/color][color=#007700]);        } catch ([/color][color=#0000bb]ioexception exc[/color][color=#007700]) {            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"read error."[/color][color=#007700]);        }        [/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();}}[/color] 

[sownlee]

xem hộ mình bài này với:
mình không làm được cho kiem tra xem file có chưa tạo nếu có rồi thì in luôn. có thể nói cho minh phương pháp được không.
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<div class="attribution type"><noscript>bai tap (move your mouse to reveal the content)</noscript>

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import java.io.datainputstream;
import java.io.dataoutputstream;
import java.io.fileinputstream;
import java.io.fileoutputstream;
import java.io.ioexception;
import java.util.scanner;
class data2byte{
public static void main(string args[]) throws ioexception {
scanner sc=new scanner(system.in);
system.out.println("nhap thong tin sinh vien: ");
system.out.print("ho ten: ");
string ten=sc.nextline();
system.out.print("nam sinh: ");
int namsinh=sc.nextint();
system.out.print("diem tb: ");
float dtb=sc.nextfloat();
sinhvien a=new sinhvien(ten,namsinh,dtb);
a.write();
a.read();
}
}
class sinhvien{
private string ten;
private int namsinh;
private float dtb;
public sinhvien(string ten,int namsinh,float dtb) throws ioexception{
this.namsinh=namsinh;
this.ten=ten;
this.dtb=dtb;
}
void write() throws ioexception{
dataoutputstream dataout = null;
try{
dataout=new dataoutputstream(new fileoutputstream("e:\\/file/sinhvien.dat"));
}catch(exception e1){
system.out.print("khong tao duoc file: ");
}
try{
dataout.writeutf(ten);
dataout.writeint(namsinh);
dataout.writefloat(dtb);;
}catch(exception e2){
system.out.print("viet file bi loi");
}
dataout.close();

}
void read()throws ioexception{
datainputstream datain=null;
try{
datain=new datainputstream(new fileinputstream("e:\\/file/sinhvien.dat"));
}catch(exception e3){
system.out.print("khong mo dc file");
}
try{
ten=datain.readutf();
system.out.println("ho ten: "+ten);
namsinh=datain.readint();
system.out.println("nam sinh: "+namsinh);
dtb=datain.readfloat();
system.out.println("diem trung binh: "+dtb);
}catch(exception e4){
system.out.print("doc file bi loi");
}
datain.close();

}

}
</blockquote></div>
</div>
</div>

[hue_xteen]

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<div class="attribution type"><noscript>myunit28 (move your mouse to reveal the content)</noscript>

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[color=#000000]
package hoc[/color][color=#007700].[/color][color=#0000bb]java[/color][color=#007700]; [/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]datainputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]file[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]dataoutputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]fileinputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]fileoutputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]ioexception[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700]; public class [/color][color=#0000bb]unit28 [/color][color=#007700]{public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string[/color][color=#007700][] [/color][color=#0000bb]args[/color][color=#007700]) [/color][color=#0000bb]throws ioexception [/color][color=#007700]{[/color][color=#0000bb]scanner sc [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);[/color][color=#0000bb]unit28 u [/color][color=#007700]= new [/color][color=#0000bb]unit28[/color][color=#007700]();[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhap duong dan file: "[/color][color=#007700]);[/color][color=#0000bb]string path [/color][color=#007700]= [/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();if ([/color][color=#0000bb]u[/color][color=#007700].[/color][color=#0000bb]checkfile[/color][color=#007700]([/color][color=#0000bb]path[/color][color=#007700]) != [/color][color=#0000bb]true[/color][color=#007700]) {[/color][color=#0000bb]u[/color][color=#007700].[/color][color=#0000bb]outputdata[/color][color=#007700]([/color][color=#0000bb]path[/color][color=#007700]);} else {[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"file da ton tai, noi dung file: "[/color][color=#007700]);[/color][color=#0000bb]u[/color][color=#007700].[/color][color=#0000bb]inputdata[/color][color=#007700]([/color][color=#0000bb]path[/color][color=#007700]);}} public [/color][color=#0000bb]boolean checkfile[/color][color=#007700]([/color][color=#0000bb]string filename[/color][color=#007700]) {[/color][color=#0000bb]file f [/color][color=#007700]= new [/color][color=#0000bb]file[/color][color=#007700]([/color][color=#0000bb]filename[/color][color=#007700]);if ([/color][color=#0000bb]f[/color][color=#007700].[/color][color=#0000bb]exists[/color][color=#007700]() == [/color][color=#0000bb]true[/color][color=#007700])return [/color][color=#0000bb]true[/color][color=#007700];elsereturn [/color][color=#0000bb]false[/color][color=#007700]; } public [/color][color=#0000bb]void inputdata[/color][color=#007700]([/color][color=#0000bb]string file[/color][color=#007700]) {try {[/color][color=#0000bb]datainputstream indata [/color][color=#007700]= new [/color][color=#0000bb]datainputstream[/color][color=#007700](new [/color][color=#0000bb]fileinputstream[/color][color=#007700]([/color][color=#0000bb]file[/color][color=#007700]));[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"noi dung file"[/color][color=#007700]);[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#0000bb]indata[/color][color=#007700].[/color][color=#0000bb]readutf[/color][color=#007700]());[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#0000bb]indata[/color][color=#007700].[/color][color=#0000bb]readint[/color][color=#007700]());[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#0000bb]indata[/color][color=#007700].[/color][color=#0000bb]readfloat[/color][color=#007700]());[/color][color=#0000bb]indata[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();} catch ([/color][color=#0000bb]ioexception exc[/color][color=#007700]) {[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"co loi xay ra: " [/color][color=#007700]+ [/color][color=#0000bb]exc[/color][color=#007700].[/color][color=#0000bb]tostring[/color][color=#007700]());}} public [/color][color=#0000bb]void outputdata[/color][color=#007700]([/color][color=#0000bb]string file[/color][color=#007700]) {try {[/color][color=#0000bb]scanner input [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);[/color][color=#0000bb]sinhvienunit28 sv [/color][color=#007700]= new [/color][color=#0000bb]sinhvienunit28[/color][color=#007700]();[/color][color=#0000bb]dataoutputstream outdata [/color][color=#007700]= new [/color][color=#0000bb]dataoutputstream[/color][color=#007700](new [/color][color=#0000bb]fileoutputstream[/color][color=#007700]([/color][color=#0000bb]file[/color][color=#007700]));[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhap ten sv: "[/color][color=#007700]);[/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]sethovaten[/color][color=#007700]([/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]());[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nam sinh: "[/color][color=#007700]);[/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]setnamsinh[/color][color=#007700]([/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]());[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"diem tb: "[/color][color=#007700]);[/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]setdiemtb[/color][color=#007700]([/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextfloat[/color][color=#007700]());[/color][color=#0000bb]outdata[/color][color=#007700].[/color][color=#0000bb]writeutf[/color][color=#007700]([/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]gethovaten[/color][color=#007700]());[/color][color=#0000bb]outdata[/color][color=#007700].[/color][color=#0000bb]writeint[/color][color=#007700]([/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]getnamsinh[/color][color=#007700]());[/color][color=#0000bb]outdata[/color][color=#007700].[/color][color=#0000bb]writefloat[/color][color=#007700]([/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]getdiemtb[/color][color=#007700]());[/color][color=#0000bb]outdata[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700](); } catch ([/color][color=#0000bb]ioexception exc[/color][color=#007700]) {[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"co loi xay ra: " [/color][color=#007700]+ [/color][color=#0000bb]exc[/color][color=#007700].[/color][color=#0000bb]tostring[/color][color=#007700]());}}} class [/color][color=#0000bb]sinhvienunit28 [/color][color=#007700]{private [/color][color=#0000bb]string hovaten[/color][color=#007700];private [/color][color=#0000bb]int namsinh[/color][color=#007700];private [/color][color=#0000bb]float diemtb[/color][color=#007700]; public [/color][color=#0000bb]string gethovaten[/color][color=#007700]() {return [/color][color=#0000bb]hovaten[/color][color=#007700];} public [/color][color=#0000bb]void sethovaten[/color][color=#007700]([/color][color=#0000bb]string hovaten[/color][color=#007700]) {[/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]hovaten [/color][color=#007700]= [/color][color=#0000bb]hovaten[/color][color=#007700];}  public [/color][color=#0000bb]int getnamsinh[/color][color=#007700]() {return [/color][color=#0000bb]namsinh[/color][color=#007700];} public [/color][color=#0000bb]void setnamsinh[/color][color=#007700]([/color][color=#0000bb]int namsinh[/color][color=#007700]) {[/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]namsinh [/color][color=#007700]= [/color][color=#0000bb]namsinh[/color][color=#007700];} public [/color][color=#0000bb]float getdiemtb[/color][color=#007700]() {return [/color][color=#0000bb]diemtb[/color][color=#007700];} public [/color][color=#0000bb]void setdiemtb[/color][color=#007700]([/color][color=#0000bb]float diemtb[/color][color=#007700]) {[/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]diemtb [/color][color=#007700]= [/color][color=#0000bb]diemtb[/color][color=#007700];} public [/color][color=#0000bb]sinhvienunit28[/color][color=#007700]() {[/color][color=#ff8000]// todo auto-generated constructor stub[/color][color=#007700]} [/color][color=#0000bb]sinhvienunit28[/color][color=#007700]([/color][color=#0000bb]string hoten[/color][color=#007700], [/color][color=#0000bb]int namsinh[/color][color=#007700], [/color][color=#0000bb]float diemtb[/color][color=#007700]) {[/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]hovaten [/color][color=#007700]= [/color][color=#0000bb]hoten[/color][color=#007700];[/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]namsinh [/color][color=#007700]= [/color][color=#0000bb]namsinh[/color][color=#007700];[/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]diemtb [/color][color=#007700]= [/color][color=#0000bb]diemtb[/color][color=#007700];}}[/color] 

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package javaandroidvn[/color][color=#007700]; [/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]datainputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]dataoutputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]file[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]fileinputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]filenotfoundexception[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]fileoutputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]ioexception[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700]; public class [/color][color=#0000bb]javaandroid6 [/color][color=#007700]{    public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string[/color][color=#007700][] [/color][color=#0000bb]args[/color][color=#007700]) {        [/color][color=#0000bb]scanner input [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);        [/color][color=#0000bb]string inputfile [/color][color=#007700]= [/color][color=#0000bb]null[/color][color=#007700];        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhập đường dẫn file:"[/color][color=#007700]);        [/color][color=#0000bb]inputfile [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();        [/color][color=#ff8000]// kiem tra xem file da ton tai chua        [/color][color=#0000bb]file file [/color][color=#007700]= new [/color][color=#0000bb]file[/color][color=#007700]([/color][color=#0000bb]inputfile[/color][color=#007700]);        [/color][color=#0000bb]sinhvien sv [/color][color=#007700]= new [/color][color=#0000bb]sinhvien[/color][color=#007700]();        if ([/color][color=#0000bb]file[/color][color=#007700].[/color][color=#0000bb]exists[/color][color=#007700]() == [/color][color=#0000bb]true[/color][color=#007700]) {            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"file đã tồn tại"[/color][color=#007700]);            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"thông tin file:" [/color][color=#007700]+ [/color][color=#0000bb]inputfile[/color][color=#007700]);            [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]readandshowfile[/color][color=#007700]([/color][color=#0000bb]inputfile[/color][color=#007700]);        } else {            [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]writefile[/color][color=#007700]([/color][color=#0000bb]inputfile[/color][color=#007700]);            [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]readandshowfile[/color][color=#007700]([/color][color=#0000bb]inputfile[/color][color=#007700]);        }         [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();    }} class [/color][color=#0000bb]sinhvien [/color][color=#007700]{    private [/color][color=#0000bb]string ten[/color][color=#007700];    private [/color][color=#0000bb]int namsinh[/color][color=#007700];    private [/color][color=#0000bb]float dtb[/color][color=#007700];     public [/color][color=#0000bb]string getten[/color][color=#007700]() {        return [/color][color=#0000bb]ten[/color][color=#007700];    }     public [/color][color=#0000bb]void setten[/color][color=#007700]([/color][color=#0000bb]string ten[/color][color=#007700]) {        [/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]ten [/color][color=#007700]= [/color][color=#0000bb]ten[/color][color=#007700];    }     public [/color][color=#0000bb]int getnamsinh[/color][color=#007700]() {        return [/color][color=#0000bb]namsinh[/color][color=#007700];    }     public [/color][color=#0000bb]void setnamsinh[/color][color=#007700]([/color][color=#0000bb]int namsinh[/color][color=#007700]) {        [/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]namsinh [/color][color=#007700]= [/color][color=#0000bb]namsinh[/color][color=#007700];    }     public [/color][color=#0000bb]float getdtb[/color][color=#007700]() {        return [/color][color=#0000bb]dtb[/color][color=#007700];    }     public [/color][color=#0000bb]void setdtb[/color][color=#007700]([/color][color=#0000bb]float dtb[/color][color=#007700]) {        [/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]dtb [/color][color=#007700]= [/color][color=#0000bb]dtb[/color][color=#007700];    }     public [/color][color=#0000bb]void writefile[/color][color=#007700]([/color][color=#0000bb]string inputfile[/color][color=#007700]) {        [/color][color=#0000bb]dataoutputstream dataout [/color][color=#007700]= [/color][color=#0000bb]null[/color][color=#007700];        try {            [/color][color=#0000bb]dataout [/color][color=#007700]= new [/color][color=#0000bb]dataoutputstream[/color][color=#007700](new [/color][color=#0000bb]fileoutputstream[/color][color=#007700]([/color][color=#0000bb]inputfile[/color][color=#007700]));        } catch ([/color][color=#0000bb]filenotfoundexception e[/color][color=#007700]) {            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"can not file"[/color][color=#007700]);            [/color][color=#ff8000]// return;            // todo auto-generated catch block            // e.printstacktrace();        [/color][color=#007700]}        [/color][color=#0000bb]scanner input [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);         try {             [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"họ tên:"[/color][color=#007700]);            [/color][color=#0000bb]ten [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();            [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writeutf[/color][color=#007700]([/color][color=#0000bb]ten[/color][color=#007700]);            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"năm sinh:"[/color][color=#007700]);            [/color][color=#0000bb]namsinh [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();            [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writeint[/color][color=#007700]([/color][color=#0000bb]namsinh[/color][color=#007700]);            [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"điểm trung bình:"[/color][color=#007700]);            [/color][color=#0000bb]dtb [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextfloat[/color][color=#007700]();            [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writefloat[/color][color=#007700]([/color][color=#0000bb]dtb[/color][color=#007700]);        } catch ([/color][color=#0000bb]ioexception e[/color][color=#007700]) {            [/color][color=#ff8000]// todo auto-generated catch block            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"error:" [/color][color=#007700]+ [/color][color=#0000bb]e[/color][color=#007700]);            [/color][color=#ff8000]// e.printstacktrace();        [/color][color=#007700]}         [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();    }     public [/color][color=#0000bb]void readandshowfile[/color][color=#007700]([/color][color=#0000bb]string inputfile[/color][color=#007700]) {        [/color][color=#0000bb]datainputstream datain [/color][color=#007700]= [/color][color=#0000bb]null[/color][color=#007700];        try {            [/color][color=#0000bb]datain [/color][color=#007700]= new [/color][color=#0000bb]datainputstream[/color][color=#007700](new [/color][color=#0000bb]fileinputstream[/color][color=#007700]([/color][color=#0000bb]inputfile[/color][color=#007700]));        } catch ([/color][color=#0000bb]filenotfoundexception e[/color][color=#007700]) {            [/color][color=#ff8000]// todo auto-generated catch block            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"không thể mở file"[/color][color=#007700]);            [/color][color=#ff8000]// e.printstacktrace();        [/color][color=#007700]}         try {            [/color][color=#0000bb]ten [/color][color=#007700]= [/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readutf[/color][color=#007700]();            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"họ tên:" [/color][color=#007700]+ [/color][color=#0000bb]ten[/color][color=#007700]);            [/color][color=#0000bb]namsinh [/color][color=#007700]= [/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readint[/color][color=#007700]();            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"năm sinh:" [/color][color=#007700]+ [/color][color=#0000bb]namsinh[/color][color=#007700]);            [/color][color=#0000bb]dtb [/color][color=#007700]= [/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readfloat[/color][color=#007700]();            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"điểm trung bình:" [/color][color=#007700]+ [/color][color=#0000bb]dtb[/color][color=#007700]);        } catch ([/color][color=#0000bb]ioexception e[/color][color=#007700]) {            [/color][color=#ff8000]// todo auto-generated catch block            [/color][color=#0000bb]e[/color][color=#007700].[/color][color=#0000bb]printstacktrace[/color][color=#007700]();        }     }}[/color] 

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[img.discovery]

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package streamdata[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]datainputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]dataoutputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]fileinputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]filenotfoundexception[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]fileoutputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]ioexception[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700];class [/color][color=#0000bb]hello[/color][color=#007700]{[/color][color=#0000bb]string name[/color][color=#007700];[/color][color=#0000bb]long birth[/color][color=#007700];[/color][color=#0000bb]double mark[/color][color=#007700]; }public class [/color][color=#0000bb]hocsinh [/color][color=#007700]{static [/color][color=#0000bb]scanner inp[/color][color=#007700];public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string[/color][color=#007700][] [/color][color=#0000bb]args[/color][color=#007700]) [/color][color=#0000bb]throws ioexception[/color][color=#007700]{[/color][color=#0000bb]hello a[/color][color=#007700]=new [/color][color=#0000bb]hello[/color][color=#007700]();[/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]name[/color][color=#007700]=[/color][color=#dd0000]"truong quang ngu"[/color][color=#007700];[/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]birth[/color][color=#007700]=[/color][color=#0000bb]1995[/color][color=#007700];[/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]mark[/color][color=#007700]=[/color][color=#0000bb]9.05[/color][color=#007700];[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]name[/color][color=#007700]+[/color][color=#dd0000]"
"[/color][color=#007700]+[/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]birth[/color][color=#007700]+[/color][color=#dd0000]"
"[/color][color=#007700]+[/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]mark[/color][color=#007700]);[/color][color=#0000bb]dataoutputstream dataout[/color][color=#007700];[/color][color=#0000bb]datainputstream datain[/color][color=#007700];[/color][color=#ff8000]//hoi dia chi luu file[/color][color=#0000bb]string add[/color][color=#007700];[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"let's input address,please..."[/color][color=#007700]);[/color][color=#0000bb]inp[/color][color=#007700]=new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);[/color][color=#0000bb]add[/color][color=#007700]=[/color][color=#0000bb]inp[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700](); try{ [/color][color=#ff8000]//neu file da ton tai thi cho in ra. [/color][color=#0000bb]datain [/color][color=#007700]=new [/color][color=#0000bb]datainputstream[/color][color=#007700](new [/color][color=#0000bb]fileinputstream[/color][color=#007700]([/color][color=#0000bb]add[/color][color=#007700]));try{[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readutf[/color][color=#007700]());}catch([/color][color=#0000bb]exception e[/color][color=#007700]){[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"no utf"[/color][color=#007700]);}try{[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readlong[/color][color=#007700]());}catch([/color][color=#0000bb]exception e[/color][color=#007700]){[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"no long"[/color][color=#007700]);}try{[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readdouble[/color][color=#007700]());}catch([/color][color=#0000bb]exception e[/color][color=#007700]){[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"no double"[/color][color=#007700]);} }catch([/color][color=#0000bb]filenotfoundexception e[/color][color=#007700]){[/color][color=#ff8000]//luc nay file chua ton tai, ta tao file moi va nhap du lieu cho no.[/color][color=#007700]try{[/color][color=#0000bb]dataout[/color][color=#007700]=new [/color][color=#0000bb]dataoutputstream[/color][color=#007700](new [/color][color=#0000bb]fileoutputstream[/color][color=#007700]([/color][color=#0000bb]add[/color][color=#007700]));}catch([/color][color=#0000bb]exception e1[/color][color=#007700]){[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"error 1"[/color][color=#007700]);return;} [/color][color=#ff8000]//input data[/color][color=#007700]try{[/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writeutf[/color][color=#007700]([/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]name[/color][color=#007700]);[/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writelong[/color][color=#007700]([/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]birth[/color][color=#007700]);[/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writedouble[/color][color=#007700]([/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]mark[/color][color=#007700]);}catch([/color][color=#0000bb]exception e2[/color][color=#007700]){[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"error 2"[/color][color=#007700]);}  [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"end 1"[/color][color=#007700]);[/color][color=#ff8000]//print[/color][color=#007700]try{[/color][color=#0000bb]datain [/color][color=#007700]=new [/color][color=#0000bb]datainputstream[/color][color=#007700](new [/color][color=#0000bb]fileinputstream[/color][color=#007700]([/color][color=#0000bb]add[/color][color=#007700]));}catch([/color][color=#0000bb]exception e3[/color][color=#007700]){[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"error 3"[/color][color=#007700]);return;} try{[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readutf[/color][color=#007700]());[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readlong[/color][color=#007700]());[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readdouble[/color][color=#007700]());}catch([/color][color=#0000bb]exception e4[/color][color=#007700]){[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"error 4"[/color][color=#007700]);}[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"end 2"[/color][color=#007700]);}}}[/color] 

[sonxemaytphcm]

ai giải thích giúp mình tại sao các lệnh write và read phải theo thứ tự thì mới chạy nếu không sẽ ra kết quả sai?
ví dụ: dout.writeutf(a);
dout.writefloat(b);
khi xuất:
din.readutf();
din.readfloat();
(đổi readfloat lên trước thì nó đọc sai).

[Hasokun112]

ai giải thích giúp mình tại sao các lệnh write và read phải theo thứ tự thì mới chạy nếu không sẽ ra kết quả sai?
ví dụ: dout.writeutf(a);
dout.writefloat(b);
khi xuất:
din.readutf();
din.readfloat();
(đổi readfloat lên trước thì nó đọc sai).

| dưỡng da

[dienthongminh]

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[color=#000000]
    [/color][color=#007700]public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string [/color][color=#007700][] [/color][color=#0000bb]args[/color][color=#007700]) [/color][color=#0000bb]throws ioexception[/color][color=#007700]{        [/color][color=#0000bb]dataoutputstream dataout [/color][color=#007700]= [/color][color=#0000bb]null[/color][color=#007700];        [/color][color=#0000bb]datainputstream datain[/color][color=#007700];              [/color][color=#0000bb]sinhvien sv [/color][color=#007700]= new [/color][color=#0000bb]sinhvien[/color][color=#007700]();        [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]ten [/color][color=#007700]= [/color][color=#dd0000]"nguyen van a"[/color][color=#007700];        [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]namsinh [/color][color=#007700]= [/color][color=#0000bb]1980[/color][color=#007700];        [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]diemtb [/color][color=#007700]= [/color][color=#0000bb]10[/color][color=#007700];              [/color][color=#0000bb]file  f [/color][color=#007700]= new [/color][color=#0000bb]file[/color][color=#007700]([/color][color=#dd0000]"d:\\sinhvien.txt"[/color][color=#007700]);        if ( ![/color][color=#0000bb]f[/color][color=#007700].[/color][color=#0000bb]exists[/color][color=#007700]()) {            try {                [/color][color=#0000bb]dataout [/color][color=#007700]= new [/color][color=#0000bb]dataoutputstream[/color][color=#007700](new [/color][color=#0000bb]fileoutputstream[/color][color=#007700]([/color][color=#dd0000]"d:\\sinhvien.txt"[/color][color=#007700]));            } catch ([/color][color=#0000bb]filenotfoundexception ex[/color][color=#007700])  {                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"file not found"[/color][color=#007700]);            }            [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writeutf[/color][color=#007700]([/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]ten[/color][color=#007700]);            [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writeint[/color][color=#007700]([/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]namsinh[/color][color=#007700]);            [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writefloat[/color][color=#007700]([/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]diemtb[/color][color=#007700]);            [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();        }        [/color][color=#0000bb]string ten[/color][color=#007700];        [/color][color=#0000bb]int ns[/color][color=#007700];        [/color][color=#0000bb]float dtb[/color][color=#007700];        [/color][color=#0000bb]datain [/color][color=#007700]= new [/color][color=#0000bb]datainputstream[/color][color=#007700](new [/color][color=#0000bb]fileinputstream[/color][color=#007700]([/color][color=#dd0000]"d:\\sinhvien.txt"[/color][color=#007700]));        [/color][color=#0000bb]ten [/color][color=#007700]= [/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readutf[/color][color=#007700]();        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"ten sinh vien: " [/color][color=#007700]+ [/color][color=#0000bb]ten[/color][color=#007700]);        [/color][color=#0000bb]ns [/color][color=#007700]= [/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readint[/color][color=#007700]();        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nam sinh: " [/color][color=#007700]+ [/color][color=#0000bb]ns[/color][color=#007700]);        [/color][color=#0000bb]dtb [/color][color=#007700]= [/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readfloat[/color][color=#007700]();        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"diem trung binh: " [/color][color=#007700]+ [/color][color=#0000bb]dtb[/color][color=#007700]);        [/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();          }}class [/color][color=#0000bb]sinhvien [/color][color=#007700]{    public [/color][color=#0000bb]string ten[/color][color=#007700];    [/color][color=#0000bb]int namsinh[/color][color=#007700];    [/color][color=#0000bb]float diemtb[/color][color=#007700];}[/color] 

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bài bạn làm quá tuyệt vời, khoa học và iq

[toyotaphumyhung]

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[color=#000000]
package baitapvenha[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]datainputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]dataoutputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]file[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]fileinputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]filenotfoundexception[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]fileoutputstream[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]io[/color][color=#007700].[/color][color=#0000bb]ioexception[/color][color=#007700];[/color][color=#0000bb]import java[/color][color=#007700].[/color][color=#0000bb]util[/color][color=#007700].[/color][color=#0000bb]scanner[/color][color=#007700];[/color][color=#ff8000]/*** bài tập về nhà: tạo đối 1 tượng sinhvien gồm các thuộc tính: tên, năm sinh,* điểm trung bình. ghi các thuộc tính này vào file theo kiểu nhị phân. đọc file* in thông tin ra ngoài. nếu chạy lại chương trình mà file đã tồn tại thì không* tạo đối tượng mới nữa mà in luôn ra thông tin đối tượng đó được đọc từ file!*/[/color][color=#007700]public class [/color][color=#0000bb]bai28 [/color][color=#007700]{    public static [/color][color=#0000bb]void main[/color][color=#007700]([/color][color=#0000bb]string[/color][color=#007700][] [/color][color=#0000bb]args[/color][color=#007700]) [/color][color=#0000bb]throws ioexception [/color][color=#007700]{       [/color][color=#0000bb]bai28 test [/color][color=#007700]= new [/color][color=#0000bb]bai28[/color][color=#007700]();       [/color][color=#0000bb]sinhvien28 sv [/color][color=#007700]= new [/color][color=#0000bb]sinhvien28[/color][color=#007700]();       [/color][color=#0000bb]string partfile [/color][color=#007700]= [/color][color=#dd0000]"e:\\thongtinsv.txt"[/color][color=#007700];       [/color][color=#0000bb]test[/color][color=#007700].[/color][color=#0000bb]writefile[/color][color=#007700]([/color][color=#0000bb]partfile[/color][color=#007700], [/color][color=#0000bb]sv[/color][color=#007700]);      [/color][color=#ff8000]/*system.out.println("
thong tin sinh vien duoc doc tu file: ");       test.readfile(partfile, sv);      */  [/color][color=#007700]}   public [/color][color=#0000bb]void writefile[/color][color=#007700]([/color][color=#0000bb]string partfile[/color][color=#007700], [/color][color=#0000bb]sinhvien28 sv[/color][color=#007700]) [/color][color=#0000bb]throws ioexception [/color][color=#007700]{       [/color][color=#0000bb]file f [/color][color=#007700]= new [/color][color=#0000bb]file[/color][color=#007700]([/color][color=#0000bb]partfile[/color][color=#007700]);       [/color][color=#0000bb]dataoutputstream dataout [/color][color=#007700]= [/color][color=#0000bb]null[/color][color=#007700];       if (![/color][color=#0000bb]f[/color][color=#007700].[/color][color=#0000bb]exists[/color][color=#007700]()) {             try {                   [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nhap thong tin sinh vien ghi vao file: "[/color][color=#007700]);                   [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]nhapsv[/color][color=#007700]();                    [/color][color=#0000bb]dataout [/color][color=#007700]= new [/color][color=#0000bb]dataoutputstream[/color][color=#007700](new [/color][color=#0000bb]fileoutputstream[/color][color=#007700]([/color][color=#0000bb]partfile[/color][color=#007700]));            } catch ([/color][color=#0000bb]filenotfoundexception e[/color][color=#007700]) {                  [/color][color=#ff8000]// todo auto-generated catch block                  [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"error: " [/color][color=#007700]+ [/color][color=#0000bb]e[/color][color=#007700]);            }            [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writeutf[/color][color=#007700]([/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]getten[/color][color=#007700]());            [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writeint[/color][color=#007700]([/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]getnamsinh[/color][color=#007700]());            [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writefloat[/color][color=#007700]([/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]getdtoan[/color][color=#007700]());            [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writefloat[/color][color=#007700]([/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]getdly[/color][color=#007700]());            [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writefloat[/color][color=#007700]([/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]getdhoa[/color][color=#007700]());            [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]writefloat[/color][color=#007700]([/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]getdiemtb[/color][color=#007700]());            [/color][color=#0000bb]dataout[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();        }        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"
thong tin sinh vien duoc doc tu file: "[/color][color=#007700]);        [/color][color=#0000bb]readfile[/color][color=#007700]([/color][color=#0000bb]partfile[/color][color=#007700], [/color][color=#0000bb]sv[/color][color=#007700]);   }    public [/color][color=#0000bb]void readfile[/color][color=#007700]([/color][color=#0000bb]string partfile[/color][color=#007700], [/color][color=#0000bb]sinhvien28 sv[/color][color=#007700]) [/color][color=#0000bb]throws ioexception [/color][color=#007700]{         [/color][color=#0000bb]datainputstream datain [/color][color=#007700]= new [/color][color=#0000bb]datainputstream[/color][color=#007700](new [/color][color=#0000bb]fileinputstream[/color][color=#007700]([/color][color=#0000bb]partfile[/color][color=#007700]));        [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]setten[/color][color=#007700]([/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readutf[/color][color=#007700]());        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"ten sinh vien: " [/color][color=#007700]+ [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]getten[/color][color=#007700]());        [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]setnamsinh[/color][color=#007700]([/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readint[/color][color=#007700]());        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"nam sinh: " [/color][color=#007700]+ [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]getnamsinh[/color][color=#007700]());        [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]setdtoan[/color][color=#007700]([/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readfloat[/color][color=#007700]());        [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]setdly[/color][color=#007700]([/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readfloat[/color][color=#007700]());        [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]setdhoa[/color][color=#007700]([/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readfloat[/color][color=#007700]());        [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]setdiemtb[/color][color=#007700]([/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]readfloat[/color][color=#007700]());        [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"diem trung binh: " [/color][color=#007700]+ [/color][color=#0000bb]sv[/color][color=#007700].[/color][color=#0000bb]getdiemtb[/color][color=#007700]());        [/color][color=#0000bb]datain[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();   }} class [/color][color=#0000bb]sinhvien28 [/color][color=#007700]{    private [/color][color=#0000bb]string ten[/color][color=#007700];    private [/color][color=#0000bb]int namsinh[/color][color=#007700];    private [/color][color=#0000bb]float dtoan[/color][color=#007700], [/color][color=#0000bb]dly[/color][color=#007700], [/color][color=#0000bb]dhoa[/color][color=#007700];    private [/color][color=#0000bb]float diemtb[/color][color=#007700];       public [/color][color=#0000bb]void nhapsv[/color][color=#007700]() {         [/color][color=#0000bb]scanner sc [/color][color=#007700]= new [/color][color=#0000bb]scanner[/color][color=#007700]([/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]in[/color][color=#007700]);         [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"ten : "[/color][color=#007700]);         [/color][color=#0000bb]ten [/color][color=#007700]= [/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();         [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nam sinh: "[/color][color=#007700]);         [/color][color=#0000bb]namsinh [/color][color=#007700]= [/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();         [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"toan : "[/color][color=#007700]);         [/color][color=#0000bb]dtoan [/color][color=#007700]= [/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextfloat[/color][color=#007700]();         [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"ly : "[/color][color=#007700]);         [/color][color=#0000bb]dly [/color][color=#007700]= [/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextfloat[/color][color=#007700]();         [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"hoa : "[/color][color=#007700]);         [/color][color=#0000bb]dhoa [/color][color=#007700]= [/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextfloat[/color][color=#007700]();   }     public [/color][color=#0000bb]string getten[/color][color=#007700]() {         return [/color][color=#0000bb]ten[/color][color=#007700];    }    public [/color][color=#0000bb]int getnamsinh[/color][color=#007700]() {        return [/color][color=#0000bb]namsinh[/color][color=#007700];    }    public [/color][color=#0000bb]float getdiemtb[/color][color=#007700]() {          return [/color][color=#0000bb]diemtb [/color][color=#007700]= ([/color][color=#0000bb]getdtoan[/color][color=#007700]()+[/color][color=#0000bb]getdly[/color][color=#007700]()+[/color][color=#0000bb]getdhoa[/color][color=#007700]()) / [/color][color=#0000bb]3[/color][color=#007700];    }    public [/color][color=#0000bb]void setten[/color][color=#007700]([/color][color=#0000bb]string ten[/color][color=#007700]) {         [/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]ten [/color][color=#007700]= [/color][color=#0000bb]ten[/color][color=#007700];    }    public [/color][color=#0000bb]void setnamsinh[/color][color=#007700]([/color][color=#0000bb]int namsinh[/color][color=#007700]) {         [/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]namsinh [/color][color=#007700]= [/color][color=#0000bb]namsinh[/color][color=#007700];    }    public [/color][color=#0000bb]void setdiemtb[/color][color=#007700]([/color][color=#0000bb]float diemtb[/color][color=#007700]) {        [/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]diemtb [/color][color=#007700]= [/color][color=#0000bb]diemtb[/color][color=#007700];    }    public [/color][color=#0000bb]float getdtoan[/color][color=#007700]() {        return [/color][color=#0000bb]dtoan[/color][color=#007700];    }    public [/color][color=#0000bb]float getdly[/color][color=#007700]() {         return [/color][color=#0000bb]dly[/color][color=#007700];    }    public [/color][color=#0000bb]float getdhoa[/color][color=#007700]() {         return [/color][color=#0000bb]dhoa[/color][color=#007700];    }    public [/color][color=#0000bb]void setdtoan[/color][color=#007700]([/color][color=#0000bb]float dtoan[/color][color=#007700]) {        [/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]dtoan [/color][color=#007700]= [/color][color=#0000bb]dtoan[/color][color=#007700];    }    public [/color][color=#0000bb]void setdly[/color][color=#007700]([/color][color=#0000bb]float dly[/color][color=#007700]) {        [/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]dly [/color][color=#007700]= [/color][color=#0000bb]dly[/color][color=#007700];    }    public [/color][color=#0000bb]void setdhoa[/color][color=#007700]([/color][color=#0000bb]float dhoa[/color][color=#007700]) {        [/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]dhoa [/color][color=#007700]= [/color][color=#0000bb]dhoa[/color][color=#007700];    } }[/color] 

</blockquote></div>
</div>
</div>

[babyfunny]

public class bangchinh {
/**
* @param args
*/
public static void main(string[] args) {
// todo auto-generated method stub
sinhvien s=new sinhvien();
s.sethoten("le nguyen hoan vu");
s.setnamsinh("20/12/1992");
s.setdiemtb(9.8);

dataoutputstream dataout;
datainputstream datain;
file filename=new file("e:\\hoanvu.dat");
try {
if (!filename.exists())
{
dataout=new dataoutputstream(new fileoutputstream(filename));
system.out.println("ghi thông tin ra file");
system.out.println("ghi tên sinh viên");
dataout.writeutf(s.gethoten());
system.out.println("ghi ngày tháng năm sinh");
dataout.writeutf(s.getnamsinh());
system.out.println("ghi điểm");
dataout.writedouble(s.getdiemtb());
dataout.close();
}
else
{
datain=new datainputstream(new fileinputstream(filename));
string s1=datain.readutf();
system.out.println("họ tên sinh viên:"+s1);
string s2=datain.readutf();
system.out.println("ngay thang nam sinh:"+s2);
double s3=datain.readdouble();
system.out.println("điểm sinh viên:"+s3);
datain.close();
}
} catch (ioexception e) {
system.out.println("không tạo được file");
return;
}

}​}​