使用Java的多线程和IO流写一个文件复制功能类

喜欢ヅ旅行 2023-07-04 14:24 37阅读 0赞

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 }