同時打開多個插座

Question

我需要在我的應用程序中同時打開2個不同的插座。一個是標準的DatagramSocket，另一個是MulticastSocket。兩者都有自己的端口。但是，當我嘗試初始化它們時，創建第二個套接字時出現錯誤。錯誤如下：

05-23 10:37:57.011: ERROR/UDPInterface(15478): Exception occurred while initializing MulticastSocket: java.net.BindException: Address already in use 

但是，因爲我使用兩個套接字分開的端口，這不可能發生，對吧？還是因爲爲MulticastSocket指定的端口已被使用？然後，該錯誤信息不會使，因爲它是在談論一個地址已在使用任何意義....：/

我創建這樣的插座：

/** 
* Initially set the UnicastSocket to use. 
* <p>Called from the constructor to create a new DatagramSocket to use 
* for receiving and sending unicast data over UDP. 
* @param address The address to initially use. 
* @param port The port to initially use. 
*/ 
private void initUnicastSocket(Inet4Address address, int port){ 
    try{ 
     mUnicastSocket = new DatagramSocket(port, address); 
     mUnicastSocket.setSoTimeout(SOCKET_TIME_OUT); 
    } catch(SocketException se){ 
     Log.e(TAG, "Exception occurred while initializing UnicastSocket: " + se.toString()); 
    } 
    if(mUnicastSocket != null){ 
     Log.d(TAG, "Socket initially set to " + 
       mUnicastSocket.getLocalAddress() + ":" + UnicastSocket.getLocalPort()); 
    } 
} 

/** 
* Initially set the BroadcastSocket to use. 
* <p>Called from the constructor to create a new MulticastSocket to use 
* for receiving and sending broadcast data over UDP. 
* @param address 
* @param port 
*/ 
private void initBroadcastSocket(Inet4Address address, int port){ 
    try { 
     mBroadcastSocket = new MulticastSocket(port); 
     mBroadcastSocket.joinGroup(address); 
     mBroadcastSocket.setSoTimeout(SOCKET_TIME_OUT); 
    } catch (IOException ioe) { 
     Log.e(TAG, "Exception occurred while initializing MulticastSocket: " + ioe.toString()); 
    } 
    if(mBroadcastSocket != null){ 
     Log.d(TAG, "MulticastSocket initially set to " + mBroadcastSocket.getLocalAddress() + 
        ":" + mBroadcastSocket.getLocalPort()); 
    } 
} 

編輯：

也值得注意的是，正常的DatagramSocket將使用設備的IP地址，並且MulticastSocket將使用可由用戶配置的IP地址。

Answer 1

我已經通過使用輔助DatagramSocket而不是MulticastSocket解決了此問題。通過設置DatagramSocket.setBroadcast(true);，我可以發送/接收廣播消息。

修訂初始化邏輯：

/** 
* Initially set the BroadcastSocket to use. 
* <p>Called from the constructor to create a new DatagramSocket to use 
* for receiving and sending broadcast data over UDP. 
* @param address 
* @param port 
*/ 
private void initBroadcastSocket(Inet4Address address, int port){ 
    try { 
     mBroadcastSocket = new DatagramSocket(port, address); 
     mBroadcastSocket.setBroadcast(true); 
     mBroadcastSocket.setSoTimeout(SOCKET_TIME_OUT); 
    } catch (IOException ioe) { 
     Log.e(TAG, "Exception occurred while initializing BroadcastSocket: " + ioe.toString()); 
    } 
    if(mBroadcastSocket != null){ 
     Log.d(TAG, "BroadcastSocket initially set to " + mBroadcastSocket.getLocalAddress() + 
        ":" + mBroadcastSocket.getLocalPort()); 
    } 
} 

謝謝大家，雖然對這個花時間對我來說雖然。

Answer 2

多播使用UDP數據包加上錯誤消息說「初始化MulticastSocket」，所以問題是多播套接字。

我建議將socket參數添加到日誌消息中。這將使調試更加簡單。

您遇到什麼可以有以下幾種原因：

1. 代碼的舊副本仍在運行
2. 還有就是設備
3. 在防火牆存在使用此端口另一個應用程序。嘗試不同的檢查