Java Socket,绑定到本地端口

Question

我试图将客户端上的Socket绑定到任何特定的本地端口,在此代码中我使用了20000.

正常连接如下面的工作正常.但是不允许我选择本地端口.

hostSocket = new Socket(host,80);

所以我尝试了这个:

hostSocket = new Socket(host, 80, InetAddress.getLocalHost(), 20000);

还有这个:

hostSocket = new Socket();
hostSocket.bind(new InetSocketAddress("localhost", 20000));
hostSocket.connect(new InetSocketAddress(host,80));

但他们都给我留下了这个例外......在第二种情况下,连接调用发生了异常.我不太确定我缺少什么,我会喜欢一些指针.

java.net.SocketException: Invalid argument or cannot assign requested address
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:327)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:193)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:180)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:384)
at java.net.Socket.connect(Socket.java:546)
at java.net.Socket.connect(Socket.java:495)
at com.mb.proxy.netflix.NetflixPrefetchingAgent.connect(NetflixPrefetchingAgent.java:98)
at com.mb.proxy.netflix.NetflixPrefetchingAgent.run(NetflixPrefetchingAgent.java:164)
at java.lang.Thread.run(Thread.java:679)
Exception in thread "Thread-19" java.lang.NullPointerException
at com.mb.proxy.netflix.NetflixPrefetchingAgent.prefetchChunk(NetflixPrefetchingAgent.java:272)
at com.mb.proxy.netflix.NetflixPrefetchingAgent.run(NetflixPrefetchingAgent.java:176)
at java.lang.Thread.run(Thread.java:679)

Answer 1

您必须绑定到计算机的外部(出站)IP地址,而不是localhost(127.0.0.1).

以下工作在我的盒子上没有问题:

Socket s = new Socket();
s.bind(new InetSocketAddress("172.16.1.102", 5000));
s.connect(new InetSocketAddress("google.com", 80));

172.16.1.102从我的路由器通过DHCP分配给此盒子的NAT'd专用网络地址在哪里.