How can I stop the server thread(and may activate it later)?

Asked Nov 01 '15 at 15:42

Active Nov 01 '15 at 16:26

Viewed 176 times

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I'm creating a multithread server that will receive message from client, process and send back the result.

The problem is when I want the server thread to stop, it won't.

Even setting the stopFlag=true, the client is still can connect to server and get the result.

How can I stop the server thread(and may activate it later)?

I tried all of these below but they didn't work.

Close listening ServerSocket

Java server socket program after one day it stops listening

Close listening ServerSocket http://tutorials.jenkov.com/java-multithreaded-servers/multithreaded-server.html

public class ServerStart implements Runnable{

private JTextArea servLog;
private boolean stopFlag=false;
public ServerStart(JTextArea servLog){
    this.servLog=servLog;
}

public void setStopFlag(boolean stop){

    stopFlag=stop;

}


@Override
public void run() {
    int port=444;
    try {
        ServerSocket serverSock = new ServerSocket(port);

        synchronized(this){
            while(!stopFlag){
                Socket clientSock=null;
                try{
                clientSock = serverSock.accept();



                }catch(IOException e){
                    if(stopFlag){
                    System.out.println("Server stop");    
                    return;
                    }
                    throw new RuntimeException("Error accepting client connection", e);

                }
                Thread listener = new Thread(new Socket_test(clientSock, port,servLog));
                listener.start();
            }

                serverSock.close();
        }




    } catch (IOException ex) {
        Logger.getLogger(ServerStart.class.getName()).log(Level.SEVERE, null, ex);
    }
}

}

edited May 23 '17 at 12:23

Community

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asked Nov 01 '15 at 15:42

raynus

195
2
8

It's good that you mention what you have already tried, but please also add what exactly didn't work when you tried each of those solutions. – RealSkeptic Nov 01 '15 at 16:03
Well, they don't show any error. The client and server run fine. The only problem is that somehow I can't close the server thread even I set the stopFlag. – raynus Nov 01 '15 at 16:06
Did you really try the third solution *exactly*? Including the fact that there are *synchronized methods* in it? – RealSkeptic Nov 01 '15 at 16:09
YES, The third solution put setSoTimeout and one comment suggest to close the server socket. But it didn't work, so I removed them and tried something else. This code is the lastest one I have. – raynus Nov 01 '15 at 16:12
No, the third solution used a synchronized method to set the stopping variable. Therefore the stopping variable's value would be visible to the server thread. That's the main point in that solution. Though simply using `volatile` would probably work as well. – RealSkeptic Nov 01 '15 at 16:17
Setting the stopflag to volatile static works for me, Thank you!!! – raynus Nov 01 '15 at 16:37

1 Answers1

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You need to interrupt your socket accept() method which is waiting on something to read from the client. A timeout on the accept could do, or calling close() from another thread

Secondly, your stopRun variable should be volatile so it can be seen on other threads when updated.

edited May 23 '17 at 11:51

Community

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answered Nov 01 '15 at 16:20

kervin

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