java知识点 --文件下载示例(多线程的使用)

package Run;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

class Main {
    public static void main(String[] args)
    {
        DownLoad d1 = new DownLoad("http://s1.music.126.net/download/pc/cloudmusicsetup_2_1_2[178132].exe");
        DownLoad d2 = new DownLoad("http://psoft.xpgod.com:801/small/emacs-_xpgod.rar");
        Thread t1 = new Thread(d1);
        Thread t2 = new Thread(d2);
        t1.start();
        t2.start();
    }
}

class DownLoad implements Runnable {

    private String stringUrl;
    
    public DownLoad(String url)
    {
        stringUrl = url;
    }
    
    private String  getFileName(String url)
    {
        char[] ch = url.toCharArray();
        int i = ch.length - 1;
        while ( ch[i] != '/')
            i--;
        char[] name = new char[ch.length - i];
        for (int j = 0; i != ch.length; ++j,++i)
            name[j] = ch[i];
        return new String(name);
    }
    
    public void run()
    {
        try {
            URL url = new URL(stringUrl);
            URLConnection con = url.openConnection();
            InputStream in = con.getInputStream();
            FileOutputStream fs = new FileOutputStream("d:/" + getFileName(stringUrl) );
            byte[] buf = new byte[1024];
            
            int bytes = -1;
            while ( (bytes = in.read(buf)) != -1)
            {
                fs.write(buf, 0, bytes);
            }
            fs.close();
        } catch (MalformedURLException e) {
            System.out.println("URL非法!");
        } catch (IOException e) {
            System.out.println("无法打开链接!");
        }
    }
}