问题
I am using a server socket in linux and I need to close it and reopen before the time_wait TCP status expires. I set the reuse address option of the server socket before the binding but it still throws a BindException. I also tried this http://meteatamel.wordpress.com/2010/12/01/socket-reuseaddress-property-and-linux/ but it still doesn't work.
To open a server socket i use:
ServerSocket ss = new ServerSocket();
ss.setReuseAddress(true);
ss.bind(new InetSocketAddress(12345));
and to close:
ss.close();
The "Address already in use" BindException is throwed at the bind call.
This code generates the exception:
for (int i = 0; i < 2; i++) {
new Thread(new Runnable() {
@Override
public void run() {
try {
final ServerSocket ss = new ServerSocket();
ss.setReuseAddress(true);
ss.bind(new InetSocketAddress(12345));
Socket s = ss.accept();
System.out.println((char) s.getInputStream().read());
ss.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
Thread.sleep(500);
Socket s = new Socket("localhost", 12345);
s.getOutputStream().write('c');
}
回答1:
You set reuse before binding not after you get an exception.
ServerSocket ss = new ServerSocket(); // don't bind just yet
ss.setReuseAddress(true);
ss.bind(new InetSocketAddress(12345)); // can bind with reuse= true
This runs without error on Windows 7 and RHEL 5.x
for (int i = 0; i < 1000; i++) {
Thread t = new Thread(new Runnable() {
@Override
public void run() {
try {
final ServerSocket ss = new ServerSocket();
ss.setReuseAddress(true);
ss.bind(new InetSocketAddress(12345));
Socket s = ss.accept();
System.out.println((char) s.getInputStream().read());
ss.close();
} catch (IOException e) {
e.printStackTrace();
}
}
});
t.start();
Thread.sleep(50);
Socket s = new Socket("localhost", 12345);
s.getOutputStream().write('c');
t.join();
}
回答2:
You have to do that: it means extract the code so that it does not recur constantly
public class....
private ServerSocket socServer;
onCreate
...
try {
socServer = new ServerSocket();
socServer.setReuseAddress(true);
socServer.bind(new InetSocketAddress(SERVER_PORT));
} catch (IOException e) {
e.printStackTrace();
}
// New thread to listen to incoming connections
new Thread(new Runnable() {
@Override
public void run() {
try
{
// Create server side client socket reference
Socket socClient = null;
// Infinite loop will listen for client requests to connect
while (true) {
// Accept the client connection and hand over communication
// to server side client socket
socClient = socServer.accept();
// For each client new instance of AsyncTask will be created
ServerAsyncTask serverAsyncTask = new ServerAsyncTask();
// Start the AsyncTask execution
// Accepted client socket object will pass as the parameter
serverAsyncTask.execute(new Socket[] {socClient});
}
} catch (IOException e) {
e.printStackTrace();
}
}
}).start();
来源:https://stackoverflow.com/questions/10516030/java-server-socket-doesnt-reuse-address