JAVA技巧:命令行多線程下載源代碼共享

/*
    *該程序采用10線程控制下載，速度大大提升
    *目前支持http協(xié)議下載
    *切換到文件所在目錄中
    *在命令行中輸入java Download5 http://...，回車，即可運(yùn)行程序
    */
    import java.io.*;
    import java.net.*;
    public class Download5 extends Thread
    {
    private long start;
    private long end;
    private String urls,name;
    private int ID;
    public Download5(String urls,String name,int ID,long start,long end)
    {
    this.start=start;
    this.end=end;
    this.urls=urls;
    this.ID=ID;
    this.name=name;
    }
    public void run()
    {
    try
    {
    System.out.println("線程"+ID+"啟動(dòng)...");
    File file=new File(name);
    URL url=new URL(urls);
    URLConnection con=url.openConnection();
    con.setAllowUserInteraction(true);
    con.setRequestProperty("Range","bytes="+start+"-"+end);
    RandomAccessFile rand=new RandomAccessFile(file,"rw");
    rand.seek(start);
    byte[] b=new byte[2048];
    BufferedInputStream buffer=new BufferedInputStream(con.getInputStream());
    int n=0;
    while((n=buffer.read(b,0,b.length))!=-1)
    {
    rand.write(b,0,n);
    }
    System.out.println("線程"+ID+"下載完畢");
    buffer.close();
    rand.close();
    this.interrupt();
    }
    catch(Exception ee)
    {
    ee.printStackTrace();
    }
    }
    public static void main(String[] args)
    {
    String urls=args[0];
    int u=urls.lastIndexOf(’/’);
    String name=urls.substring(u+1,urls.length());
    try
    {
    long time=System.currentTimeMillis()/1000;
    URL url=new URL(urls);
    URLConnection con=url.openConnection();
    int filelength=con.getContentLength();
    int num=10;
    int size=filelength/num;
    Download5 t=null;
    CountTime count=new CountTime(urls,name,time);
    count.start();
    for(int i=0;i    {
    if(i!=num-1)
    {
    t=new Download5(urls,name,i+1,size*i,size*(i+1)-1);
    t.start();
    }
    else
    {
    t=new Download5(urls,name,i+1,size*i,filelength);
    t.start();
    }
    }
    }
    catch(Exception ee)
    {
    ee.printStackTrace();
    }
    }
    }
    class CountTime extends Thread
    {
    private String urls,name;
    private long time;
    public CountTime(String urls,String name,long time)
    {
    this.urls=urls;
    this.name=name;
    this.time=time;
    }
    public void run()
    {
    try
    {
    URL url=new URL(urls);
    URLConnection con=url.openConnection();
    int filelength=con.getContentLength();
    File f=new File(name);
    while(f.length()    {
    long LEN=f.length();
    this.sleep(1000);
    System.out.println((f.length()-LEN)/1024/1.0+"kb/s");
    }
    System.out.println("文件下載完畢");
    System.out.println("下載所用總時(shí)間: "+(System.currentTimeMillis()/1000-time)+"s");
    this.interrupt();
    }
    catch(Exception e)
    {
    e.printStackTrace();
    }
    }
    }