how can i stop the block method DatagramSocket.receive() in a thread

Question

i create a DatagramSocket in the main thread,and then create a inner class thread to listen the port. when i close the DatagramSocket in the main t

Answer 1

Close the socket, which will stop the receive() call from blocking. If you first set a closed flag then in the catch (IOException) block you can safely ignore the exception if the flag is set. (You could probably also use isClosed() method on DatagramSocket instead of a flag)

Answer 2

Socket.close() does the trick. Or you can use socket.setSoTimeout(1000); the setSoTimeout() method allows you to define a timeout period in milliseconds. For example:

//if the socket does not receive anything in 1 second, 
//it will timeout and throw a SocketTimeoutException
//you can catch the exception if you need to log, or you can ignore it
socket.setSoTimeout(1000); 
socket.receive();

Here is the javadoc for setSoTimeout();

By default, the timeout is 0 which is indefinite, by changing it to a positive number, it will only block for the amount you specified. (Make sure you set it before calling socket.receive())

Here is an example answered on this site: set timeout for socket receive

Answer 3

With UDP, you could send the socket a datagram from another thread, so unblocking the read(). The datagran could, (depending on your protocol), contain a 'suicide' command or you could use an additional 'shutdown' boolean that the thread reads after read() returns.