Question

So, my server app causing a huge cpu usage averaging about 95%. I think the reason is it keep spawning new thread but not closing it. how am I suppose to close a thread when any of this happen: refresh page, logout, browser closed.

My code is more or less like this for server part.

ThreadedEchoServer.java

public class ThreadedEchoServer {
    // using port 2000
    static final int PORT = 2000;

    public static void main(String args[]) {
        ServerSocket serverSocket = null;
        Socket socket = null;

        try {
            serverSocket = new ServerSocket(PORT);
        } catch (IOException e) {
            e.printStackTrace();

        }
        while (true) {
            try {
                socket = serverSocket.accept();
            } catch (IOException e) {
                System.out.println("I/O error: " + e);
            }

            // new thread for a client
            new EchoThread(socket).start();
        }
    }
}

EchoThread.java

/*
Class for java server to accept incoming stream
and create a new thread to save log file data in server
*/
public class EchoThread extends Thread {
    protected Socket socket;

    public EchoThread(Socket clientSocket) {
        this.socket = clientSocket;
    }

    public void run() {
        /*Create a File*/
        int i = 1;
        try {
            File directory = new File("F:/temp/tmplog/" + getDate());
            if(!directory.exists()) {
                directory.mkdir();
            }

            String fileName = "F:/temp/tmplog/" + getDate() + "/" + getDateTime() + ".txt";
            File file = new File(fileName);

            //Double Make Sure it create the file
            while(file.exists()) {
                file = new File(fileName + "." + i);
                i++;
            }
            FileOutputStream fis = new FileOutputStream(file, true);
            PrintStream out = new PrintStream(fis);
            System.setOut(out);


            while (true) {
              try {
                InputStream is = socket.getInputStream();
                BufferedReader br = new BufferedReader(new InputStreamReader(is, "US-ASCII"));

                String line = null;

                while ((line = br.readLine()) != null) {
                  System.out.println(line);
                }
              } catch (IOException exception) {
                // Just handle next request.
              } finally {
                if (socket != null) {
                  try {
                    socket.close();
                  } catch (IOException ignored) {
                  }
                }
                fis.close();
              }
            }


        } catch (IOException ignored) {
        }
    }

This server app basicly will open a new and write a log file for every thread/client. I think the problem is I do not close the thread after use. that’s why it just keep spawning new thread.. Any help?

Answer 1

If I understood what you’re looking for, you can just use a timeout to handle this situation.
When the timeout expires, you’ll just terminate the thread.

EchoThread

/*
Class for java server to accept incoming stream
and create a new thread to save log file data in server
*/
public class EchoThread extends Thread {
    protected Socket socket;

    public EchoThread(Socket clientSocket) {
        this.socket = clientSocket;
        this.socket.setSoTimeout(10000); //Sets timeout to 10 seconds
    }

    public void run() {
        /*Create a File*/
        int i = 1;
        try {
            File directory = new File("F:/temp/tmplog/" + getDate());
            if(!directory.exists()) {
                directory.mkdir();
            }

            String fileName = "F:/temp/tmplog/" + getDate() + "/" + getDateTime() + ".txt";
            File file = new File(fileName);

            //Double Make Sure it create the file
            while(file.exists()) {
                file = new File(fileName + "." + i);
                i++;
            }
            FileOutputStream fis = new FileOutputStream(file, true);
            PrintStream out = new PrintStream(fis);
            System.setOut(out);


            while (true) {
              try {
                InputStream is = socket.getInputStream();
                BufferedReader br = new BufferedReader(new InputStreamReader(is, "US-ASCII"));

                String line = null;

                while ((line = br.readLine()) != null) {
                  System.out.println(line);
                }
              } catch (IOException exception) {
                // Just handle next request.
              } finally {
                if (socket != null) {
                  try {
                    socket.close();
                  } catch (IOException ignored) {
                  }
                }
                fis.close();
              }
            }


        } catch (IOException ignored) {
        } catch (SocketException e) { //Exception thrown by timeout
            socket.close(); //We close the socket
            this.stop(); //We stop the thread
        }
    }