DatagramSocket总是发送UDP数据后无法接收数据

ref:http://blog.chinaunix.net/uid-20771867-id-3416509.html
         cmd：telnet localhost 5554
        redir add udp:8002:8001 (将PC 8002端口映射为模拟器 8001端口)
         模拟器-SERVER：ServerSocket server = new ServerSocket(8001);//zcl:7100改为2888
            public static void ReceiveUDP() throws IOException {
             // TODO Auto-generated method stub
ReliableUDP udp = new ReliableUDP(null, "172.17.21.231", 8001, 8001);
             byte[] revBuf = new byte[1024];
             int res = udp.ReadFixedLength(revBuf, 1);
            }                     
         PC-CLIENT：Socket socket = new Socket("127.0.0.1", 8002); 
          《TCP/UDP测试工具》 UDP:127.0.0.1 port 8002 (注意：8002是PC的映射端口) 

ok ——》 最终找到原因：是redir add会抢占端口:          
ok ——》解决方法：环境设置——关键是一定要使用remotePC，单靠本机无法实现调试
  

      +++++++++++++++++++++++++++++++++++++++++          +++++++++++++++++++++++++++++++++++++++++
      +    localPC                            +          +          remotePC                     +
      +    ip:172.17.22.8                     +          +        ip:172.17.21.54                +
      +     redir udp:8002:8001               +          +                                       +
      +                                       +          +                                       +
      +   +++++++++++++++++++++++++++++       +          +                                       +
      +   + android vm                +       +          +                                       +
      +   +                           +       +          +                                       +
      +   +                           +       +          +                                       +
      +   +  send(DestIP=remotePC,    +       +          +         Receive(localPort=8001)       +
      +   +       localPort=8001)     +       +          +                                       +
      +   +       DestPort=8001)      +       +          +                                       +
      +   +       -----8001--------------------------------->  8001                              -
      +   +                           +       +          +                                       +
      +   +                           +       +          +                                       +
      +   +  Receive(localPort=8001), +       +          +        send(  DestIP=localPC          +
      +   +                           +       +          +                localPort=8001)        +
      +   +                           +       +          +                DestPort=8002)         +
      +   +                           +       +          +                                       +
      +   +            8001<----------+---8002<----------+-----8001                              +
      +   +                           +       +          +                                       +
      +   +                           +       +          +                                       +
      +   +++++++++++++++++++++++++++++       +          +                                       +
      +                                       +          +                                       +
      +++++++++++++++++++++++++++++++++++++++++          +++++++++++++++++++++++++++++++++++++++++
        

ok ——》code：
   public class LEDControlerDriver {
    public static void SendUDP() {
     // TODO Auto-generated method stub
     ReliableUDP udp = new ReliableUDP(null, DestIP, 8001, 8001);//to lydsw 前一个8001是模拟器-SERVER port，后一个8001是pc 接收消息的port，注意！不是pc映射给模拟器的端口(8002)
     String s= "32323213";
     int res = udp.SendFixedLength(s.getBytes(), s.length()); 
     
    }
    
    public static void ReceiveUDP() throws IOException {
     // TODO Auto-generated method stub
     ReliableUDP udp = new ReliableUDP(null, DestIP, 8001, 8001);//to lydsw 前一个8001是模拟器-SERVER port，后一个8001是pc 接收消息的port，注意！不是pc映射给模拟器的端口(8002)
     byte[] revBuf = new byte[1];
     int res = udp.ReadFixedLength(revBuf, 1);
    }
                 
   public class ReliableUDP {
    public int SendFixedLength(byte[] sendBuf,int nSendLen){
     Log.i("UDP Demo", "发送数据(1):");
     // check
        int res = 1;
        if (sendBuf.length!=nSendLen) {
      return -2;
     } 
       
        // create socket
        DatagramSocket socket = null;
     try {
      socket = new DatagramSocket(null);   // 指定Null很重要，否则Java会自动随机选个可用端口来绑定
      socket.setReuseAddress(true); // DatagramSocket的setReuseAddress(true)方法执行后，可以允许多个DatagramSocket
              // 绑定到相同的IP地址和端口，那么发送到此IP地址和端口的数据能够被复制到多个DatagramSocket
      socket.setSoTimeout(10000);
      socket.bind(new InetSocketAddress(this.LocalPort)); 
     } catch (SocketException e) {
      Log.i("UDP Demo", "SendFixedLength:socket create failed1:"+e.getMessage());
      return -3;
     }     
       
        Log.i("UDP Demo", "发送数据(2):");
        // 定义一个用于发送的DatagramPacket对象 
        DatagramPacket outPacket = null;
        try {
                outPacket = new DatagramPacket(sendBuf , nSendLen  , InetAddress.getByName(this.IPaddr) , this.TargetPort); 
                   socket.send(outPacket); 
                   Log.i("UDP Demo", "SendData:UDP发送数据:"+StringHexbyteTransform.bytesToHexString(sendBuf));
     } catch (IOException e2) {
      Log.i("UDP Demo", "SendData:io failed:"+e2.toString()+":"+e2.getMessage());
      res = -52;
     }  
       
        socket.close();
        return res;
    }
                                                   
                                                  
    public int ReadFixedLength(byte[] revBuf,int nRecvLen, int timeout)
    {
     Log.i("UDP Demo", "Read数据(1):");
     // check
        int res = 1;
        int len = nRecvLen;
        if (-1 == nRecvLen) {
         len = revBuf.length;
     } 
       
        // create socket
        DatagramSocket socket = null;
     try {
      socket = new DatagramSocket(null);   // 指定Null很重要，否则Java会自动随机选个可用端口来绑定
      socket.setReuseAddress(true); // DatagramSocket的setReuseAddress(true)方法执行后，可以允许多个DatagramSocket
              // 绑定到相同的IP地址和端口，那么发送到此IP地址和端口的数据能够被复制到多个DatagramSocket
      socket.setSoTimeout(timeout);
      socket.bind(new InetSocketAddress(this.LocalPort)); 
     } catch (SocketException e) {
      Log.i("UDP Demo", "SendFixedLength:socket create failed1:"+e.getMessage());
      return -3;
     }     
       
        Log.i("UDP Demo", "Read数据(2):");
        // 定义一个用于发送的DatagramPacket对象 
        DatagramPacket inPacket = null;
        try {
          inPacket = new DatagramPacket(revBuf , len);
          socket.receive(inPacket); 
          ExpandRevBuffer(revBuf);
                   Log.i("UDP Demo", "receive:"+StringHexbyteTransform.bytesToHexString(revBuf)); 
     } catch (IOException e2) {
      Log.i("UDP Demo", "SendData:io failed:"+e2.toString()+":"+e2.getMessage());
      res = -52;
     }  
       
        socket.close();
        return res;
    }