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：

 import java.io.*;

 import java.text.DecimalFormat;

 /**

  * 文件复制类

  * @author Administrator

  *

  */

 public class FileCopy extends Thread {

     private File src;//待读取的源文件

     private File dest;//待写入的目标文件

     public FileCopy(String src,String dest){

         this.src = new File(src);

         this.dest = new File(dest);

     }

     @Override

     public void run() {

         FileInputStream is = null;

         FileOutputStream os = null;

         try {

             is = new FileInputStream(src);

             os = new FileOutputStream(dest);

             byte[] b = new byte[1024];

             int length = 0;

             //获取源文件大小

             long len = src.length();

             //已复制文件的字节数

             double temp = 0 ;

             //数字格式化，显示百分比

             DecimalFormat df = new DecimalFormat("##.00%");

             while((length = is.read(b))!=-1){

                 //输出字节

                 os.write(b, 0, length);

                 //获取已下载的大小，并且转换成百分比

                 temp += length;

                 double d = temp/len;

                 System.out.println(src.getName()+"已复制的进度："+df.format(d));

             }

             System.out.println(src.getName()+"复制完成！");

         } catch (FileNotFoundException e) {

             e.printStackTrace();

         } catch (IOException e) {

             e.printStackTrace();

         }finally{

             try {

                 if (is != null) {

                     is.close();

                 }

                 if(os!=null){

                     os.close();

                 }

             } catch (Exception e) {

                 e.printStackTrace();

             }

         }

     }

 }

在测试类中调用复制功能类

 public class FileCopyTest {

     public static void main(String[] args) {

         FileCopy cf = new FileCopy("D:\\720.txt","D:\\test\\1.txt");

         FileCopy cf2 = new FileCopy("D:\\721.txt","D:\\test\\2.txt");

         FileCopy cf3 = new FileCopy("D:\\123.txt","D:\\test\\3.txt");

         cf.start();

         cf2.start();

         cf3.start();

     }

 }