Android 多线程下载



	 

	package my.Thread; 

	 

	import java.io.BufferedInputStream; 

	import java.io.RandomAccessFile; 

	import java.net.HttpURLConnection; 

	import java.net.URL; 

	import java.net.URLConnection; 

	import java.util.concurrent.CountDownLatch; 

	 

	 

	import android.app.Activity; 

	import android.os.Bundle; 

	import android.os.Environment; 

	import android.view.View; 

	import android.view.View.OnClickListener; 

	import android.widget.Button; 

	import android.widget.TextView; 

	 

	public class ManyThreadActivity extends Activity { 

	    /** Called when the activity is first created. */ 

	     private Button button; 

	     private TextView textView; 

	     private static final int THREAD_COUNT = 4; 

	     private CountDownLatch latch = new CountDownLatch(THREAD_COUNT); 

	     private long completeLength = 0; 

	     private long fileLength; 

	     public static String SaveFile=Environment.getExternalStorageDirectory()+"/DownFile/"+"test.Mp3";   

	     public static final String url="http://210.30.12.33:8080/mp3/Beyond.mp3"; 

	    @Override 

	    public void onCreate(Bundle savedInstanceState) { 

	        super.onCreate(savedInstanceState); 

	        setContentView(R.layout.main); 

	        button=(Button)findViewById(R.id.button1); 

	        textView=(TextView) findViewById(R.id.editText1); 

	        textView.setText(url); 

	        button.setOnClickListener(new MyListener()); 

	    } 

	    class MyListener implements OnClickListener{ 

	 

	        @Override 

	        public void onClick(View v) { 

	            // TODO Auto-generated method stub 

	            try { 

	                download(url); 

	            } catch (Exception e) { 

	                // TODO Auto-generated catch block 

	                e.printStackTrace(); 

	            } 

	        } 

	         

	    } 

	 

	    //进行下载的线程 

	    class DownloadThread extends Thread { 

	        private URL url; 

	        private RandomAccessFile file; 

	        private long from; 

	        private long end; 

	 

	        /**

	         * @param url 下载的URL

	         * @param file 下载完成之后存储的文件

	         * @param from 当前线程对应文件的起始位置

	         * @param end 当前线程对应文件的结束位置

	         */ 

	        DownloadThread(URL url, RandomAccessFile file, long from, long end) { 

	            this.url = url; 

	            this.file = file; 

	            this.from = from; 

	            this.end = end; 

	        } 

	 

	        public void run() { 

	            try { 

	                long pos = from; 

	                byte[] buf = new byte[1024*8]; 

	 

	                HttpURLConnection cn = (HttpURLConnection) url.openConnection(); 

	                

	                //设置请求的起始和结束位置。 

	                cn.setRequestProperty("Range", "bytes=" + from + "-" + end); 

	 

	                BufferedInputStream bis = new BufferedInputStream(cn.getInputStream()); 

	                int len; 

	                while ((len = bis.read(buf)) > 0) { 

	                    synchronized (file) { 

	                        file.seek(pos); 

	                        file.write(buf, 0, len); 

	                    } 

	                    pos += len; 

	                    completeLength += len; 

	                    System.out.println(completeLength * 100 / fileLength + "%"); 

	                } 

	                cn.disconnect();

补充：移动开发 , Android ,