使用Java的多线程和IO流写一个文件复制功能类

创建一个复制功能类，继承Thread类，重写run()方法，把FileInputStream和FileOutputStream输入输出流写在run()方法内。示例代码如下：

 1 import java.io.*;
 2 import java.text.DecimalFormat;
 3 /**
 4  * 文件复制类
 5  * @author Administrator
 6  *
 7  */
 8 public class FileCopy extends Thread {
 9     
10     private File src;//待读取的源文件
11     private File dest;//待写入的目标文件
12     
13     public FileCopy(String src,String dest){
14         this.src = new File(src);
15         this.dest = new File(dest);
16     }
17 
18     @Override
19     public void run() {
20         FileInputStream is = null;
21         FileOutputStream os = null;
22         
23         try {
24             is = new FileInputStream(src);
25             os = new FileOutputStream(dest);
26             
27             byte[] b = new byte[1024];
28             int length = 0;
29             
30             //获取源文件大小
31             long len = src.length();
32             //已复制文件的字节数
33             double temp = 0 ; 
34             //数字格式化，显示百分比
35             DecimalFormat df = new DecimalFormat("##.00%");
36             while((length = is.read(b))!=-1){
37                 //输出字节
38                 os.write(b, 0, length);
39                 //获取已下载的大小，并且转换成百分比
40                 temp += length;
41                 double d = temp/len;
42                 System.out.println(src.getName()+"已复制的进度："+df.format(d));
43             }
44             System.out.println(src.getName()+"复制完成！");
45             
46         } catch (FileNotFoundException e) {
47             e.printStackTrace();
48         } catch (IOException e) {
49             e.printStackTrace();
50         }finally{
51             try {
52                 if (is != null) {
53                     is.close();
54                 } 
55                 if(os!=null){
56                     os.close();
57                 }
58             } catch (Exception e) {
59                 e.printStackTrace();
60             }
61         }
62                 
63     }
64 
65 }

在测试类中调用复制功能类

 1 public class FileCopyTest {
 2 
 3     public static void main(String[] args) {
 4 
 5         FileCopy cf = new FileCopy("D:\720.txt","D:\test\1.txt");
 6         FileCopy cf2 = new FileCopy("D:\721.txt","D:\test\2.txt");
 7         FileCopy cf3 = new FileCopy("D:\123.txt","D:\test\3.txt");
 8         cf.start();
 9         cf2.start();
10         cf3.start();
11         
12     }
13 
14 }