Bài 27: Đọc và ghi file dùng luồng byte trong Java

[van7deal]

mấy anh ơi cho em hỏi tý. mấy bài trên em thấy dòng: fileinputstream filein = null; nó có nghĩa gì vậy, cám ơn ạ

[thegioimaytap]

ok đã tham khảo 1 số ý kiến chuyên gia và có 1 số nhận xét như sau:
return trong catch tránh được mấy lỗi ở phía sau:
vd:nullpointerexception ở hai câu lệnh close cho cái fin va fout ay
cai return trong catch
fin = new fileinputstream("e:\\in.mp3");
fout = new fileoutputstream("e:\\out.mp3");

nếu exception xảy ra mà ko có return thì code sẽ gặp giá trị num values ở fin.close(); fout.close() phía dưới.

nếu không dùng return; thì code như thế nào bạn?

[longlong495321]

bài n

mấy anh ơi cho em hỏi tý. mấy bài trên em thấy dòng: fileinputstream filein = null; nó có nghĩa gì vậy, cám ơn ạ

bài nào bạn.bạn phải nói rõ vào phần trả lời đó.theo mình đó chỉ là một cách khởi tạo thôi.có thể null hoặc new fileinputstream() cũng tạo ra 1 đối tượng mặc định cũng là null..

[hoabaybay]

mới làm cái move với delete
<div class="bbcodeblock bbcodequote bbcmspoilerblock">
<div class="attribution type"><noscript>bl (move your mouse to reveal the content)</noscript>

bl (open)
bl (close)

</div>
<div class="quotecontent">
<div class="bbcm_spoiler_noscript"><blockquote>

[color=#000000]
package javaandroidvn[/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]javaandroidvn4 [/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]string option [/color][color=#007700]= [/color][color=#0000bb]null[/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=#ff8000]// string k;             [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhập lựa chọn---coppy-----delete:"[/color][color=#007700]);            [/color][color=#0000bb]option [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();            [/color][color=#0000bb]int a [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700];             if ([/color][color=#0000bb]option[/color][color=#007700].[/color][color=#0000bb]equals[/color][color=#007700]([/color][color=#dd0000]"coppy"[/color][color=#007700]))                [/color][color=#0000bb]a [/color][color=#007700]= [/color][color=#0000bb]1[/color][color=#007700];            [/color][color=#ff8000]// if(option.equals("move"))            // a = 2;            [/color][color=#007700]if ([/color][color=#0000bb]option[/color][color=#007700].[/color][color=#0000bb]equals[/color][color=#007700]([/color][color=#dd0000]"delete"[/color][color=#007700]))                [/color][color=#0000bb]a [/color][color=#007700]= [/color][color=#0000bb]2[/color][color=#007700];             switch ([/color][color=#0000bb]a[/color][color=#007700]) {            case [/color][color=#0000bb]1[/color][color=#007700]:                [/color][color=#0000bb]string fileinput[/color][color=#007700],                [/color][color=#0000bb]fileoutput[/color][color=#007700];                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"đường dẫn file vào:"[/color][color=#007700]);                [/color][color=#0000bb]fileinput [/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]"đường dẫn file ra"[/color][color=#007700]);                [/color][color=#0000bb]fileoutput [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();                 try {                    [/color][color=#0000bb]coppy[/color][color=#007700]([/color][color=#0000bb]fileinput[/color][color=#007700], [/color][color=#0000bb]fileoutput[/color][color=#007700]);                } catch ([/color][color=#0000bb]ioexception 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]"lỗi khi đọc ghi file:" [/color][color=#007700]+ [/color][color=#0000bb]e[/color][color=#007700]);                    [/color][color=#ff8000]// todo auto-generated catch block                    // e.printstacktrace();                [/color][color=#007700]}                break;            case [/color][color=#0000bb]2[/color][color=#007700]:                 [/color][color=#0000bb]string soufile[/color][color=#007700];                [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"đường dẫn file vào:"[/color][color=#007700]);                [/color][color=#0000bb]soufile [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();                [/color][color=#0000bb]delete[/color][color=#007700]([/color][color=#0000bb]soufile[/color][color=#007700]);                 break;            case [/color][color=#0000bb]3[/color][color=#007700]:                break;            }            [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();        } catch ([/color][color=#0000bb]exception e[/color][color=#007700]) {         }        [/color][color=#ff8000]// input.close();    [/color][color=#007700]}     public static [/color][color=#0000bb]void coppy[/color][color=#007700]([/color][color=#0000bb]string fileinput[/color][color=#007700], [/color][color=#0000bb]string fileoutput[/color][color=#007700])            [/color][color=#0000bb]throws ioexception [/color][color=#007700]{        [/color][color=#ff8000]// scanner input1 = new scanner(system.in);        // string fileinput;        // system.out.println("nhập đường dẫn của file cần coppy:");        // fileinput = input1.nextline();        [/color][color=#0000bb]fileinputstream fin [/color][color=#007700]= [/color][color=#0000bb]null[/color][color=#007700];         try {            [/color][color=#0000bb]fin [/color][color=#007700]= new [/color][color=#0000bb]fileinputstream[/color][color=#007700]([/color][color=#0000bb]fileinput[/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]"lỗi file nhập"[/color][color=#007700]);            [/color][color=#ff8000]// e.printstacktrace();        [/color][color=#007700]}         [/color][color=#ff8000]// string fileoutput;        // system.out.println("nhập đường dẫn tên file sau khi coppy:");        // fileoutput = input1.nextline();        [/color][color=#0000bb]fileoutputstream fout [/color][color=#007700]= [/color][color=#0000bb]null[/color][color=#007700];         try {            [/color][color=#0000bb]fout [/color][color=#007700]= new [/color][color=#0000bb]fileoutputstream[/color][color=#007700]([/color][color=#0000bb]fileoutput[/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]"lỗi file xuất"[/color][color=#007700]);            [/color][color=#ff8000]// e.printstacktrace();        [/color][color=#007700]}         [/color][color=#ff8000]// coppy        [/color][color=#0000bb]int i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700];        do {            [/color][color=#0000bb]i [/color][color=#007700]= [/color][color=#0000bb]fin[/color][color=#007700].[/color][color=#0000bb]read[/color][color=#007700]();            if ([/color][color=#0000bb]i [/color][color=#007700]!= -[/color][color=#0000bb]1[/color][color=#007700])                [/color][color=#0000bb]fout[/color][color=#007700].[/color][color=#0000bb]write[/color][color=#007700]([/color][color=#0000bb]i[/color][color=#007700]);        } while ([/color][color=#0000bb]i [/color][color=#007700]!= -[/color][color=#0000bb]1[/color][color=#007700]);         [/color][color=#0000bb]fin[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();        [/color][color=#0000bb]fout[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();        [/color][color=#ff8000]// input1.close();    [/color][color=#007700]}     public static [/color][color=#0000bb]void delete[/color][color=#007700]([/color][color=#0000bb]string soufile[/color][color=#007700]) {        try {            [/color][color=#0000bb]file file [/color][color=#007700]= [/color][color=#0000bb]null[/color][color=#007700];            [/color][color=#0000bb]file [/color][color=#007700]= new [/color][color=#0000bb]file[/color][color=#007700]([/color][color=#0000bb]soufile[/color][color=#007700]);            [/color][color=#0000bb]scanner in [/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].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"bạn có chắc muốn xóa file?(y/n)"[/color][color=#007700]);            [/color][color=#0000bb]string lc [/color][color=#007700]= [/color][color=#0000bb]in[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();             if ([/color][color=#0000bb]lc[/color][color=#007700].[/color][color=#0000bb]equals[/color][color=#007700]([/color][color=#dd0000]"y"[/color][color=#007700])) {                [/color][color=#0000bb]file[/color][color=#007700].[/color][color=#0000bb]delete[/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]"xóa thành công"[/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]"lệnh xóa đã bị hủy"[/color][color=#007700]);            }            [/color][color=#0000bb]in[/color][color=#007700].[/color][color=#0000bb]close[/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]"error:" [/color][color=#007700]+ [/color][color=#0000bb]e[/color][color=#007700]);         }     }}[/color] 

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

[kinhvrgiare9]

theo mình nghĩ biến int i sẽ nhận gía trị trả về là các số 0 1 sau đó lệnh in print sẽ dịch i ra thành dạng char
mình đã bỏ (char) và kết quả ra toàn là số thôi

nó đọc theo giá trị ascii của kí tự bạn ạ

[dinhduongchobe]

@tiasangmoi92 và mọi người xem bài này hộ em có cần chỉnh sửa thêm gì nữa không với ạ, em cám ơn
<div class="bbcodeblock bbcodequote bbcmspoilerblock">
<div class="attribution type"><noscript>bai 27 (move your mouse to reveal the content)</noscript>

bai 27 (open)
bai 27 (close)

</div>
<div class="quotecontent">
<div class="bbcm_spoiler_noscript"><blockquote>

[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]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]/*** biến màn hình console thành màn hình lệnh như sau: - nếu bạn gõ từ "copy",* thì chương trình sẽ hỏi địa chỉ file cần copy, bạn gõ địa chỉ file cần copy* vào, nếu không tồn tại sẽ bắt nhập lại, nếu tồn tại sẽ hỏi địa chỉ file đích,* sau đó chương trình sẽ copy file đó. tương tự với các lệnh "move", "delete" -* gợi ý cách xóa file: thêm 2 dòng lệnh như ví dụ này là bạn có thể xóa được 1* file:*//** hd: nhap file nguon va dich:* nhap lenh muon thuc hien :* ===> menu  enter the choose: 1** -- this is coppy --* nhap dia chi file muon coppy: d:\\filename.txt* nhap dia chi file part2 muon ghi ra: d:\\copyfile.txt** -- this is delete --* nhap dia chi file muon delete: e:\\filetest.txt** -- this is move --* nhap dia chi file muon move: d:\\ghilai.txt* nhap vi tri file chuyen den: e:\\**/[/color][color=#007700]public class [/color][color=#0000bb]buoi27 [/color][color=#007700]{     static [/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]);     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]buoi27 test [/color][color=#007700]= new [/color][color=#0000bb]buoi27[/color][color=#007700]();          [/color][color=#0000bb]string part1[/color][color=#007700], [/color][color=#0000bb]part2[/color][color=#007700];          [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhap lenh muon thuc hien :"[/color][color=#007700]);          [/color][color=#0000bb]int lenh [/color][color=#007700]= [/color][color=#0000bb]test[/color][color=#007700].[/color][color=#0000bb]choose[/color][color=#007700]();          [/color][color=#0000bb]boolean b [/color][color=#007700]= [/color][color=#0000bb]true[/color][color=#007700];          while ([/color][color=#0000bb]b[/color][color=#007700]) {                switch ([/color][color=#0000bb]lenh[/color][color=#007700]) {                     case [/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]"
-- this is coppy --"[/color][color=#007700]);                           [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhap dia chi file muon coppy: "[/color][color=#007700]);                           [/color][color=#0000bb]part1 [/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]"nhap dia chi file part2 muon ghi ra: "[/color][color=#007700]);                           [/color][color=#0000bb]part2 [/color][color=#007700]= [/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();                           [/color][color=#0000bb]test[/color][color=#007700].[/color][color=#0000bb]copyfile[/color][color=#007700]([/color][color=#0000bb]part1[/color][color=#007700], [/color][color=#0000bb]part2[/color][color=#007700]);                           [/color][color=#0000bb]lenh [/color][color=#007700]= [/color][color=#0000bb]test[/color][color=#007700].[/color][color=#0000bb]choose[/color][color=#007700]();                           break;                     case [/color][color=#0000bb]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]"
-- this is delete --"[/color][color=#007700]);                           [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhap dia chi file muon delete: "[/color][color=#007700]);                           [/color][color=#0000bb]part1 [/color][color=#007700]= [/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();                           [/color][color=#0000bb]test[/color][color=#007700].[/color][color=#0000bb]deletefile[/color][color=#007700]([/color][color=#0000bb]part1[/color][color=#007700]);                           [/color][color=#0000bb]lenh [/color][color=#007700]= [/color][color=#0000bb]test[/color][color=#007700].[/color][color=#0000bb]choose[/color][color=#007700]();                           break;                    case [/color][color=#0000bb]3[/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]"
-- this is move --"[/color][color=#007700]);                          [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"nhap dia chi file muon move: "[/color][color=#007700]);                          [/color][color=#0000bb]part1 [/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]"nhap vi tri file chuyen den: "[/color][color=#007700]);                          [/color][color=#0000bb]part2 [/color][color=#007700]= [/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();                          [/color][color=#0000bb]test[/color][color=#007700].[/color][color=#0000bb]movefile[/color][color=#007700]([/color][color=#0000bb]part1[/color][color=#007700], [/color][color=#0000bb]part2[/color][color=#007700]);                          [/color][color=#0000bb]lenh [/color][color=#007700]= [/color][color=#0000bb]test[/color][color=#007700].[/color][color=#0000bb]choose[/color][color=#007700]();                          break;                    case [/color][color=#0000bb]4[/color][color=#007700]:                          [/color][color=#0000bb]b [/color][color=#007700]= [/color][color=#0000bb]false[/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]"exit application! "[/color][color=#007700]);                          [/color][color=#0000bb]system[/color][color=#007700].exit([/color][color=#0000bb]0[/color][color=#007700]);                   default:                           [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"the number \"" [/color][color=#007700]+ [/color][color=#0000bb]lenh[/color][color=#007700]+ [/color][color=#dd0000]"\" not valid in system! please try again:"[/color][color=#007700]);                           [/color][color=#0000bb]lenh [/color][color=#007700]= [/color][color=#0000bb]test[/color][color=#007700].[/color][color=#0000bb]choose[/color][color=#007700]();                   }          }      }       public [/color][color=#0000bb]void listoperator[/color][color=#007700]() {           [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"
===> menu <==="[/color][color=#007700]);            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"
1. copy"[/color][color=#007700]);            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"
2. delete"[/color][color=#007700]);            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"
3. move"[/color][color=#007700]);            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"
4. exit"[/color][color=#007700]);            [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].print([/color][color=#dd0000]"
 ==> enter the choose: "[/color][color=#007700]);      }       public [/color][color=#0000bb]int choose[/color][color=#007700]() {            [/color][color=#0000bb]int choose [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700];            [/color][color=#0000bb]listoperator[/color][color=#007700]();            try {                 [/color][color=#0000bb]choose [/color][color=#007700]= [/color][color=#0000bb]integer[/color][color=#007700].[/color][color=#0000bb]parseint[/color][color=#007700]([/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]());            } catch ([/color][color=#0000bb]exception e[/color][color=#007700]) {                [/color][color=#ff8000]// todo: handle exception                  [/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]);            }            return [/color][color=#0000bb]choose[/color][color=#007700];     }       public [/color][color=#0000bb]void copyfile[/color][color=#007700]([/color][color=#0000bb]string part1[/color][color=#007700], [/color][color=#0000bb]string part2[/color][color=#007700]) [/color][color=#0000bb]throws ioexception [/color][color=#007700]{           [/color][color=#0000bb]fileinputstream inputfile [/color][color=#007700]= [/color][color=#0000bb]null[/color][color=#007700];           [/color][color=#0000bb]fileoutputstream outputfile [/color][color=#007700]= [/color][color=#0000bb]null[/color][color=#007700];           try {                [/color][color=#0000bb]inputfile [/color][color=#007700]= new [/color][color=#0000bb]fileinputstream[/color][color=#007700]([/color][color=#0000bb]part1[/color][color=#007700]);                [/color][color=#0000bb]outputfile [/color][color=#007700]= new [/color][color=#0000bb]fileoutputstream[/color][color=#007700]([/color][color=#0000bb]part2[/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]"file not found : " [/color][color=#007700]+ [/color][color=#0000bb]e[/color][color=#007700]);               return;               [/color][color=#ff8000]// todo: handle exception          [/color][color=#007700]} catch ([/color][color=#0000bb]arrayindexoutofbound***ception 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]"usage: copyfile from to"[/color][color=#007700]);               return;          } catch ([/color][color=#0000bb]exception e[/color][color=#007700]) {                [/color][color=#ff8000]// todo: handle exception               [/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]int i[/color][color=#007700];          try {                  do {                           [/color][color=#0000bb]i [/color][color=#007700]= [/color][color=#0000bb]inputfile[/color][color=#007700].[/color][color=#0000bb]read[/color][color=#007700]();                           if ([/color][color=#0000bb]i [/color][color=#007700]!= -[/color][color=#0000bb]1[/color][color=#007700])                             [/color][color=#0000bb]outputfile[/color][color=#007700].[/color][color=#0000bb]write[/color][color=#007700]([/color][color=#0000bb]i[/color][color=#007700]);                  } while ([/color][color=#0000bb]i [/color][color=#007700]!= -[/color][color=#0000bb]1[/color][color=#007700]);          } catch ([/color][color=#0000bb]ioexception e[/color][color=#007700]) {                 [/color][color=#ff8000]// todo: handle exception                 [/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]inputfile[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();         [/color][color=#0000bb]outputfile[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();    }     public [/color][color=#0000bb]void deletefile[/color][color=#007700]([/color][color=#0000bb]string partfile[/color][color=#007700]) {         try {                 [/color][color=#0000bb]file file [/color][color=#007700]= new [/color][color=#0000bb]file[/color][color=#007700]([/color][color=#0000bb]partfile[/color][color=#007700]);                 [/color][color=#0000bb]file[/color][color=#007700].[/color][color=#0000bb]delete[/color][color=#007700]();         } catch ([/color][color=#0000bb]exception e[/color][color=#007700]) {                 [/color][color=#ff8000]// todo: handle exception                 [/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]);                 return;         }    }      public [/color][color=#0000bb]void movefile[/color][color=#007700]([/color][color=#0000bb]string part1[/color][color=#007700], [/color][color=#0000bb]string part2[/color][color=#007700]) {            try {                     [/color][color=#0000bb]string str[/color][color=#007700][] = [/color][color=#0000bb]part1[/color][color=#007700].[/color][color=#0000bb]split[/color][color=#007700]([/color][color=#dd0000]"\\\\"[/color][color=#007700]);                     [/color][color=#0000bb]part2 [/color][color=#007700]+=[/color][color=#0000bb]str[/color][color=#007700][[/color][color=#0000bb]str[/color][color=#007700].[/color][color=#0000bb]length[/color][color=#007700]-[/color][color=#0000bb]1[/color][color=#007700]];                     [/color][color=#0000bb]copyfile[/color][color=#007700]([/color][color=#0000bb]part1[/color][color=#007700], [/color][color=#0000bb]part2[/color][color=#007700]);                     [/color][color=#0000bb]deletefile[/color][color=#007700]([/color][color=#0000bb]part1[/color][color=#007700]);            } catch ([/color][color=#0000bb]exception e[/color][color=#007700]) {                     [/color][color=#ff8000]// todo: handle exception                     [/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] 

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

[tienphatvn]

catch có return trả giá trị cho f, nếu không f sẽ không đc khai báo giá trị và k thể đọc hay viết đc. nếu k muốn return thì lúc khai báo cho một giá trị cho f. để null chẳng hạn

[duongtuyet01]

public class docghifile {
/**
* @param args
*/
public static void main(string[] args) {

system.out.println("nhập vào chữ cần");
bufferedreader bf=new bufferedreader(new inputstreamreader(system.in));
try {
string ch=bf.readline();
switch (ch) {
case "copy":
system.out.println("nhập địa chỉ file cần copy");
string diachi;
file file,file1 = null;
do
{
diachi=bf.readline();
file=new file("e:\\"+diachi);
}while(!file.exists());
if (file.exists())
{
system.out.println("nhap vao file đích");
string dich=bf.readline();
file1=new file("e:\\"+dich);
}
fileinputstream f=new fileinputstream(file);
fileoutputstream fout=new fileoutputstream(file1);
int i;
do
{
i=f.read();
if (i!=-1)
{
fout.write(i);
}
}while (i!=-1);
f.close();
fout.close();
break;
case "delete":
system.out.println("nhap vao dia chi file can delete");
string diachi1=bf.readline();
file f1=new file("e:\\"+diachi1);
f1.delete();
break;
case "move":
system.out.println("nhap vao dia chi file muon di chuyen");
string diachi2=bf.readline();
file f2=new file("e:\\"+diachi2);
f2.renameto(new file("d:\\"+diachi2));
break;
default:
system.out.print("nhập chưa hợp lệ");
break;
}

} catch (ioexception e) {
e.printstacktrace();
}
}
}

[toyotavp]

<div class="bbcodeblock bbcodequote bbcmspoilerblock">
<div class="attribution type"><noscript>spoiler (move your mouse to the spoiler area to reveal the content)</noscript>

show spoiler
hide spoiler

</div>
<div class="quotecontent">
<div class="bbcm_spoiler_noscript"><blockquote>

[color=#000000]
[/color][color=#007700]public class [/color][color=#0000bb]unit27 [/color][color=#007700]{       private [/color][color=#0000bb]string out[/color][color=#007700];    private [/color][color=#0000bb]string in[/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]);       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]unit27 u [/color][color=#007700]= new [/color][color=#0000bb]unit27[/color][color=#007700]();        [/color][color=#0000bb]u[/color][color=#007700].[/color][color=#0000bb]choice[/color][color=#007700]();    }          public [/color][color=#0000bb]void choice[/color][color=#007700]() [/color][color=#0000bb]throws ioexception [/color][color=#007700]{        [/color][color=#0000bb]int i[/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]"---------------------"[/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]"1.copy 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]"2.move 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]"3.delete 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]"---------------------"[/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]"moi chon thao tac:"[/color][color=#007700]);        [/color][color=#0000bb]i [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();        [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();        while([/color][color=#0000bb]i [/color][color=#007700]> [/color][color=#0000bb]3 [/color][color=#007700]|| [/color][color=#0000bb]i [/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]"ban da nhap sai, moi nhap lai:"[/color][color=#007700]);            [/color][color=#0000bb]i [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextint[/color][color=#007700]();            [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();        }               switch([/color][color=#0000bb]i[/color][color=#007700]) {            case [/color][color=#0000bb]1[/color][color=#007700]: [/color][color=#0000bb]copy[/color][color=#007700]();                break;            case [/color][color=#0000bb]2[/color][color=#007700]: [/color][color=#0000bb]move[/color][color=#007700]();                break;            case [/color][color=#0000bb]3[/color][color=#007700]: [/color][color=#0000bb]delete[/color][color=#007700]();                break;            default: [/color][color=#0000bb]system[/color][color=#007700].[/color][color=#0000bb]out[/color][color=#007700].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"bye bye"[/color][color=#007700]);                break;        }    }       public [/color][color=#0000bb]void copy[/color][color=#007700]() [/color][color=#0000bb]throws ioexception [/color][color=#007700]{        [/color][color=#ff8000]//mở file nguồn        //while(true) là vòng lặp vô hạn nên trong thân vòng lặp luôn có lệnh break               [/color][color=#0000bb]fileinputstream fin[/color][color=#007700];        [/color][color=#0000bb]fileoutputstream fout[/color][color=#007700];               while([/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]"nhập tên file cần copy:"[/color][color=#007700]);            [/color][color=#0000bb]in [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();            try {                [/color][color=#0000bb]fin [/color][color=#007700]= new [/color][color=#0000bb]fileinputstream[/color][color=#007700]([/color][color=#dd0000]"e:\\" [/color][color=#007700]+ [/color][color=#0000bb]in[/color][color=#007700]);                break;            } 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]"error:" [/color][color=#007700]+ [/color][color=#0000bb]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]"không thấy file cần tìm, mời nhập lại."[/color][color=#007700]);            }        }               [/color][color=#ff8000]//mở file đích        [/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 tên file đích:"[/color][color=#007700]);        [/color][color=#0000bb]out [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();        try {            [/color][color=#0000bb]fout [/color][color=#007700]= new [/color][color=#0000bb]fileoutputstream[/color][color=#007700]([/color][color=#dd0000]"e:\\" [/color][color=#007700]+ [/color][color=#0000bb]out[/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]"error:" [/color][color=#007700]+ [/color][color=#0000bb]e[/color][color=#007700]);            return;        }               [/color][color=#ff8000]// copy dữ liệu        [/color][color=#0000bb]int i[/color][color=#007700];        try {            do {                [/color][color=#0000bb]i [/color][color=#007700]= [/color][color=#0000bb]fin[/color][color=#007700].[/color][color=#0000bb]read[/color][color=#007700]();                if([/color][color=#0000bb]i [/color][color=#007700]!= -[/color][color=#0000bb]1[/color][color=#007700]) {                    [/color][color=#0000bb]fout[/color][color=#007700].[/color][color=#0000bb]write[/color][color=#007700]([/color][color=#0000bb]i[/color][color=#007700]);                }            } while([/color][color=#0000bb]i [/color][color=#007700]!= -[/color][color=#0000bb]1[/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]"error:" [/color][color=#007700]+ [/color][color=#0000bb]e[/color][color=#007700]);            return;        }        [/color][color=#ff8000]//đóng file        [/color][color=#0000bb]fout[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();        [/color][color=#0000bb]fin[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();    }       [/color][color=#ff8000]//muốn move 1 file, có 2 cách    //cách 1: sử dụng file.renameto()    //cách 2: copy file gốc sang 1 file khác và xóa file gốc, cách này làm sau    //dưới đây là cách 1; cách này phải sử dụng lớp file, chắc là lớp cha các lớp    // fileinputstream, fileoutputstream    [/color][color=#007700]public [/color][color=#0000bb]void move[/color][color=#007700]() {        [/color][color=#ff8000]// mở file đích        [/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 file cần di chuyển"[/color][color=#007700]);        [/color][color=#0000bb]in [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();            [/color][color=#ff8000]// nhập tên file và đường dẫn cần chuyển file đến        [/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 tên file đích:"[/color][color=#007700]);        [/color][color=#0000bb]out [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();        try {            [/color][color=#0000bb]file file1 [/color][color=#007700]= new [/color][color=#0000bb]file[/color][color=#007700]([/color][color=#dd0000]"e:\\" [/color][color=#007700]+ [/color][color=#0000bb]in[/color][color=#007700]);            if([/color][color=#0000bb]file1[/color][color=#007700].[/color][color=#0000bb]renameto[/color][color=#007700](new [/color][color=#0000bb]file[/color][color=#007700]([/color][color=#dd0000]"d:\\" [/color][color=#007700]+ [/color][color=#0000bb]out[/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]"move file thành công"[/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]"error:" [/color][color=#007700]+ [/color][color=#0000bb]e[/color][color=#007700]);        }    }       public [/color][color=#0000bb]void delete[/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 file can xoa"[/color][color=#007700]);        [/color][color=#0000bb]in [/color][color=#007700]= [/color][color=#0000bb]input[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();        try {            [/color][color=#0000bb]file f [/color][color=#007700]= new [/color][color=#0000bb]file[/color][color=#007700]([/color][color=#dd0000]"e:\\" [/color][color=#007700]+ [/color][color=#0000bb]in[/color][color=#007700]);            [/color][color=#0000bb]f[/color][color=#007700].[/color][color=#0000bb]delete[/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]"error:" [/color][color=#007700]+ [/color][color=#0000bb]e[/color][color=#007700]);        }           }   }[/color] 

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

[gangcuone]

mong các bạn đóng góp ý kiến

[color=#000000]
[/color][color=#007700]public class [/color][color=#0000bb]copymovedeletefile [/color][color=#007700]{public static [/color][color=#0000bb]void copyfile[/color][color=#007700]() [/color][color=#0000bb]throws ioexception [/color][color=#007700]{[/color][color=#0000bb]fileinputstream fin [/color][color=#007700]= [/color][color=#0000bb]null[/color][color=#007700];[/color][color=#0000bb]fileoutputstream fout [/color][color=#007700]= [/color][color=#0000bb]null[/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]boolean bol [/color][color=#007700]= [/color][color=#0000bb]true[/color][color=#007700];[/color][color=#0000bb]string address1[/color][color=#007700], [/color][color=#0000bb]address2[/color][color=#007700];try {for ([/color][color=#0000bb]int i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]bol [/color][color=#007700]== [/color][color=#0000bb]true[/color][color=#007700]; [/color][color=#0000bb]i[/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]"address file you want to copy"[/color][color=#007700]);[/color][color=#0000bb]address1 [/color][color=#007700]= [/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();[/color][color=#0000bb]fin [/color][color=#007700]= new [/color][color=#0000bb]fileinputstream[/color][color=#007700]([/color][color=#0000bb]address1[/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]"address file you want to save and new name for file"[/color][color=#007700]);[/color][color=#0000bb]address2 [/color][color=#007700]= [/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();[/color][color=#0000bb]fout [/color][color=#007700]= new [/color][color=#0000bb]fileoutputstream[/color][color=#007700]([/color][color=#0000bb]address2[/color][color=#007700]); [/color][color=#0000bb]bol [/color][color=#007700]= [/color][color=#0000bb]false[/color][color=#007700];} catch ([/color][color=#0000bb]filenotfoundexception e[/color][color=#007700]) {[/color][color=#0000bb]bol [/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]"input file not found"[/color][color=#007700]);}}} catch ([/color][color=#0000bb]arrayindexoutofbound***ception 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]"usage: copyfile from to"[/color][color=#007700]);return;}[/color][color=#0000bb]int j[/color][color=#007700];try {do {[/color][color=#0000bb]j [/color][color=#007700]= [/color][color=#0000bb]fin[/color][color=#007700].[/color][color=#0000bb]read[/color][color=#007700]();if ([/color][color=#0000bb]j [/color][color=#007700]!= -[/color][color=#0000bb]1[/color][color=#007700]) {[/color][color=#0000bb]fout[/color][color=#007700].[/color][color=#0000bb]write[/color][color=#007700]([/color][color=#0000bb]j[/color][color=#007700]);}} while ([/color][color=#0000bb]j [/color][color=#007700]!= -[/color][color=#0000bb]1[/color][color=#007700]);} catch ([/color][color=#0000bb]exception 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]"file error"[/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]"copy finish "[/color][color=#007700]);[/color][color=#0000bb]fin[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();[/color][color=#0000bb]fout[/color][color=#007700].[/color][color=#0000bb]close[/color][color=#007700]();}public static [/color][color=#0000bb]void delete[/color][color=#007700]() [/color][color=#0000bb]throws ioexception [/color][color=#007700]{[/color][color=#0000bb]file fin [/color][color=#007700]= [/color][color=#0000bb]null[/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]boolean bol [/color][color=#007700]= [/color][color=#0000bb]true[/color][color=#007700];try {for ([/color][color=#0000bb]int i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]bol [/color][color=#007700]== [/color][color=#0000bb]true[/color][color=#007700]; [/color][color=#0000bb]i[/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]"address file you want to delete"[/color][color=#007700]);[/color][color=#0000bb]string address [/color][color=#007700]= [/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();[/color][color=#0000bb]fin [/color][color=#007700]= new [/color][color=#0000bb]file[/color][color=#007700]([/color][color=#0000bb]address[/color][color=#007700]);if([/color][color=#0000bb]fin[/color][color=#007700].[/color][color=#0000bb]delete[/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]"delete complete"[/color][color=#007700]);[/color][color=#0000bb]bol [/color][color=#007700]= [/color][color=#0000bb]false[/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]"file not found"[/color][color=#007700]);}}} catch ([/color][color=#0000bb]arrayindexoutofbound***ception 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]"usage: copyfile from to"[/color][color=#007700]);return;}[/color][color=#0000bb]fin[/color][color=#007700].[/color][color=#0000bb]exists[/color][color=#007700]();}public static [/color][color=#0000bb]void move[/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]file afile [/color][color=#007700]= [/color][color=#0000bb]null[/color][color=#007700];[/color][color=#0000bb]string address1[/color][color=#007700], [/color][color=#0000bb]address2[/color][color=#007700];[/color][color=#0000bb]boolean bol [/color][color=#007700]= [/color][color=#0000bb]true[/color][color=#007700];try {for ([/color][color=#0000bb]int i [/color][color=#007700]= [/color][color=#0000bb]0[/color][color=#007700]; [/color][color=#0000bb]bol [/color][color=#007700]== [/color][color=#0000bb]true[/color][color=#007700]; [/color][color=#0000bb]i[/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]"address file you want to move"[/color][color=#007700]);[/color][color=#0000bb]address1 [/color][color=#007700]= [/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();[/color][color=#0000bb]afile [/color][color=#007700]=new [/color][color=#0000bb]file[/color][color=#007700]([/color][color=#0000bb]address1[/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]"where to move"[/color][color=#007700]);[/color][color=#0000bb]address2 [/color][color=#007700]= [/color][color=#0000bb]sc[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700]();if([/color][color=#0000bb]afile[/color][color=#007700].[/color][color=#0000bb]renameto[/color][color=#007700](new [/color][color=#0000bb]file[/color][color=#007700]([/color][color=#0000bb]address2[/color][color=#007700]+[/color][color=#dd0000]"" [/color][color=#007700]+ [/color][color=#0000bb]afile[/color][color=#007700].[/color][color=#0000bb]getname[/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]"finish"[/color][color=#007700]);[/color][color=#0000bb]bol [/color][color=#007700]= [/color][color=#0000bb]false[/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]"input file not found"[/color][color=#007700]);}}} catch ([/color][color=#0000bb]arrayindexoutofbound***ception 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]"usage: copyfile from to"[/color][color=#007700]);return;}}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 sc2 [/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].[/color][color=#0000bb]println[/color][color=#007700]([/color][color=#dd0000]"you want :"[/color][color=#007700]);[/color][color=#0000bb]string question [/color][color=#007700]= [/color][color=#0000bb]sc2[/color][color=#007700].[/color][color=#0000bb]nextline[/color][color=#007700](); if ([/color][color=#0000bb]question[/color][color=#007700].[/color][color=#0000bb]equals[/color][color=#007700]([/color][color=#dd0000]"copy"[/color][color=#007700])) {[/color][color=#0000bb]copyfile[/color][color=#007700]();} else if ([/color][color=#0000bb]question[/color][color=#007700].[/color][color=#0000bb]equals[/color][color=#007700]([/color][color=#dd0000]"move"[/color][color=#007700])) {[/color][color=#0000bb]move[/color][color=#007700]();} else if ([/color][color=#0000bb]question[/color][color=#007700].[/color][color=#0000bb]equals[/color][color=#007700]([/color][color=#dd0000]"delete"[/color][color=#007700])) {[/color][color=#0000bb]delete[/color][color=#007700]();}}}[/color]