java 第四次作业

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;


public class FileCopy {
   
public static void copy(File a,File b){
    try
    {
        int bytesum = 0;
        int byteread = 0;
        File oldfile = new File( "E:/java/copyfile/a.mp3");
        if ( oldfile.exists() )
        { //文件存在时
            InputStream inStream = new FileInputStream( "E:/java/copyfile/a.mp3" ); //读入原文件
            FileOutputStream fs = new FileOutputStream( "E:/java/copyfile/b.mp3" );
            byte[] buffer = new byte[ 1444 ];
            int length;
            while ( ( byteread = inStream.read( buffer ) ) != -1 )
            {
                bytesum += byteread; //字节数 文件大小
                
                fs.write( buffer, 0, byteread );
            }
            inStream.close();
        }
    }
    catch ( Exception e )
    {
        System.out.println( "复制单个文件操作出错" );
        e.printStackTrace();}
    
}
public static void main(String[] args)
   {
      


               File a = new File("");
               File b = new File("");
               long start,end;
               start = System.currentTimeMillis();
               copy(a,b);
               end = System.currentTimeMillis();
               System.out.println("复制所用时间：" + (end - start) + "ms");
           }
   


}