Bài 15: Phương thức setter và getter trong Java

[hangnguyencvht2009]

mình cũng khá hiểu phần đó rồi chỉ là không hiểu tại sao ta không cho lớp khác truy nhập :dnếu ta dùng public thì không cần phải dùng getter và setter như thế thì khỏe hơn chứ ops:mới qua hướng đối tượng hơi bỡ ngỡ :d

[superheo79]

mình cũng khá hiểu phần đó rồi chỉ là không hiểu tại sao ta không cho lớp khác truy nhập :dnếu ta dùng public thì không cần phải dùng getter và setter như thế thì khỏe hơn chứ ops:mới qua hướng đối tượng hơi bỡ ngỡ :d

nôm na là giống như tăng tính bảo mật của các lớp í..

[qatgroup]

mình cũng khá hiểu phần đó rồi chỉ là không hiểu tại sao ta không cho lớp khác truy nhập :dnếu ta dùng public thì không cần phải dùng getter và setter như thế thì khỏe hơn chứ ops:mới qua hướng đối tượng hơi bỡ ngỡ :d

cái này thể hiện tính bảo mật thôi :d nếu biến nào của bạn cũng để public tức là lớp nào cũng có thể truy cập được thì bên ngoài cũng rất dễ xâm nhập gọi đến và lấy thông tin, vì thế ta mới cần phải để private

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import java.util.calendar;
import java.util.scanner;
class hanghoa{
public string tenhang;
public string mahang;
public double giahang;
public int soluong;
public double tong(double giahang, int soluong){
return giahang*soluong;
}
public double sale(double tong, double gio){
if(gio>=8&&gio<=17){
return tong*95/100;
}else return tong;
}

}
public class run {
public static void main(string []args){

calendar c=calendar.getinstance();
double gio=c.get(calendar.hour_of_day);
scanner schuoi=new scanner(system.in);
scanner sint=new scanner(system.in);
hanghoa a=new hanghoa();
system.out.print("nhập tên hàng: ");
a.tenhang=schuoi.nextline();
system.out.print("nhập mã hàng: ");
a.mahang=schuoi.nextline();
system.out.print("nhập giá hàng: ");
a.giahang=sint.nextdouble();
system.out.print("nhập số lượng: ");
a.soluong=sint.nextint();
system.out.println("số tiền phải thanh toán là: "+a.sale(a.tong(a.giahang, a.soluong), gio));

}


}
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[minhquanpham2]

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package nhansu[/color][color=#007700];class [/color][color=#0000bb]sv[/color][color=#007700]{private [/color][color=#0000bb]string hotensv[/color][color=#007700];private [/color][color=#0000bb]string lophoc[/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];public [/color][color=#0000bb]string gethotensv[/color][color=#007700]() {return [/color][color=#0000bb]hotensv[/color][color=#007700];}public [/color][color=#0000bb]void sethotensv[/color][color=#007700]([/color][color=#0000bb]string hotensv[/color][color=#007700]) {[/color][color=#0000bb]hotensv [/color][color=#007700]= [/color][color=#0000bb]hotensv[/color][color=#007700];}public [/color][color=#0000bb]string getlophoc[/color][color=#007700]() {return [/color][color=#0000bb]lophoc[/color][color=#007700];}public [/color][color=#0000bb]void setlophoc[/color][color=#007700]([/color][color=#0000bb]string lophoc[/color][color=#007700]) {[/color][color=#0000bb]lophoc [/color][color=#007700]= [/color][color=#0000bb]lophoc[/color][color=#007700];}public [/color][color=#0000bb]float getdtoan[/color][color=#007700]() {return [/color][color=#0000bb]dtoan[/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]float getdly[/color][color=#007700]() {return [/color][color=#0000bb]dly[/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]float getdhoa[/color][color=#007700]() {return [/color][color=#0000bb]dhoa[/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] 

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package nhansu[/color][color=#007700];class [/color][color=#0000bb]gv [/color][color=#007700]{private [/color][color=#0000bb]string hotengv[/color][color=#007700];private [/color][color=#0000bb]string lopday[/color][color=#007700];private [/color][color=#0000bb]int ns[/color][color=#007700];private [/color][color=#0000bb]int luong[/color][color=#007700];public [/color][color=#0000bb]string gethotengv[/color][color=#007700]() {return [/color][color=#0000bb]hotengv[/color][color=#007700];}public [/color][color=#0000bb]void sethotengv[/color][color=#007700]([/color][color=#0000bb]string hotengv[/color][color=#007700]) {[/color][color=#0000bb]hotengv [/color][color=#007700]= [/color][color=#0000bb]hotengv[/color][color=#007700];}public [/color][color=#0000bb]string getlopday[/color][color=#007700]() {return [/color][color=#0000bb]lopday[/color][color=#007700];}public [/color][color=#0000bb]void setlopday[/color][color=#007700]([/color][color=#0000bb]string lopday[/color][color=#007700]) {[/color][color=#0000bb]lopday [/color][color=#007700]= [/color][color=#0000bb]lopday[/color][color=#007700];}public [/color][color=#0000bb]int getns[/color][color=#007700]() {return [/color][color=#0000bb]ns[/color][color=#007700];}public [/color][color=#0000bb]void setns[/color][color=#007700]([/color][color=#0000bb]int ns[/color][color=#007700]) {[/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]ns [/color][color=#007700]= [/color][color=#0000bb]ns[/color][color=#007700];}public [/color][color=#0000bb]int getluong[/color][color=#007700]() {return [/color][color=#0000bb]luong[/color][color=#007700];}public [/color][color=#0000bb]void setluong[/color][color=#007700]([/color][color=#0000bb]int luong[/color][color=#007700]) {[/color][color=#0000bb]this[/color][color=#007700].[/color][color=#0000bb]luong [/color][color=#007700]= [/color][color=#0000bb]luong[/color][color=#007700];}         }[/color] 

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package nhansu[/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]qlnhansu  [/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 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]sv a[/color][color=#007700]=new [/color][color=#0000bb]sv[/color][color=#007700]();[/color][color=#0000bb]gv b[/color][color=#007700]=new [/color][color=#0000bb]gv[/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 hoc sinh a"[/color][color=#007700]);[/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]sethotensv[/color][color=#007700]([/color][color=#0000bb]inp[/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]"nhap lop hoc sinh a"[/color][color=#007700]);[/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]setlophoc[/color][color=#007700]([/color][color=#0000bb]inp[/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 diem ly"[/color][color=#007700]);[/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]setdly[/color][color=#007700]([/color][color=#0000bb]inp[/color][color=#007700].[/color][color=#0000bb]nextfloat[/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 toan"[/color][color=#007700]);[/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]setdtoan[/color][color=#007700]([/color][color=#0000bb]inp[/color][color=#007700].[/color][color=#0000bb]nextfloat[/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 hoa"[/color][color=#007700]);[/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]setdhoa[/color][color=#007700]([/color][color=#0000bb]inp[/color][color=#007700].[/color][color=#0000bb]nextfloat[/color][color=#007700]()); [/color][color=#0000bb]float dtb[/color][color=#007700];[/color][color=#0000bb]dtb[/color][color=#007700]=([/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]getdhoa[/color][color=#007700]()+[/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]getdly[/color][color=#007700]()+[/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]getdtoan[/color][color=#007700]())/[/color][color=#0000bb]3[/color][color=#007700];[/color][color=#0000bb]dtb[/color][color=#007700]=[/color][color=#0000bb]math[/color][color=#007700].[/color][color=#0000bb]round[/color][color=#007700]([/color][color=#0000bb]dtb[/color][color=#007700]*[/color][color=#0000bb]10[/color][color=#007700])/[/color][color=#0000bb]10[/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 cua a la"[/color][color=#007700]+([/color][color=#0000bb]dtb[/color][color=#007700]));if ([/color][color=#0000bb]dtb[/color][color=#007700]>=[/color][color=#0000bb]8 [/color][color=#007700]&& [/color][color=#0000bb]dtb[/color][color=#007700]<=[/color][color=#0000bb]10[/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]"a la  hoc sinh gioi"[/color][color=#007700]) ;} else {if ([/color][color=#0000bb]dtb[/color][color=#007700]<[/color][color=#0000bb]8 [/color][color=#007700]&& [/color][color=#0000bb]dtb[/color][color=#007700]>[/color][color=#0000bb]6.5[/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]"a la hoc sinh kha"[/color][color=#007700]);}else { if ([/color][color=#0000bb]dtb[/color][color=#007700]<=[/color][color=#0000bb]6.5 [/color][color=#007700]&& [/color][color=#0000bb]dtb[/color][color=#007700]>=[/color][color=#0000bb]5[/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]"a la hoc sinh trung binh"[/color][color=#007700]);} else { if ([/color][color=#0000bb]dtb[/color][color=#007700]<[/color][color=#0000bb]5 [/color][color=#007700]&& [/color][color=#0000bb]dtb[/color][color=#007700]>=[/color][color=#0000bb]1[/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]"a la hoc sinh yeu :)"[/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]"nhap sai"[/color][color=#007700]);[/color][color=#0000bb]system[/color][color=#007700].exit([/color][color=#0000bb]0[/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 lop day cua giao vien b"[/color][color=#007700]);[/color][color=#0000bb]b[/color][color=#007700].[/color][color=#0000bb]setlopday[/color][color=#007700]([/color][color=#0000bb]inp[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]());if ([/color][color=#0000bb]a[/color][color=#007700].[/color][color=#0000bb]getlophoc[/color][color=#007700]()==[/color][color=#0000bb]b[/color][color=#007700].[/color][color=#0000bb]getlopday[/color][color=#007700]()){[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"a co day b"[/color][color=#007700]); } else {[/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"a khong day b"[/color][color=#007700]);  }}}   [/color] 

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