为什么超时后我的Java服务器程序无法退出？

Question

I've been trying to solve the consumer-producer problem using a client-server pair connected via sockets on my own system. It's been going well enough so far, but only one problem remains. My server program won't exit after the time out, while the client does.

The client code I've got is shown below:

import java.util.*;
import java.net.*;
import java.io.*;

public class ConsumerClient {
    protected static boolean done = false;
    private static InetAddress host;
    private static final int PORT = 4545;

    private static BufferedReader inS;
    private static PrintWriter outS;
    private static Socket link;

    static class Consumer implements Runnable {
        Random random = new Random();

        @Override
        public void run() {
            try {
                while(true) {
                    String recieved;
                    try {
                        outS.println("1");
                    } catch(Exception e) {
                        System.out.println(e);
                    }
                    recieved = inS.readLine();
                    System.out.println("Recieved object: " + recieved);
                    if(done) {
                        System.out.println("Consumer done.");
                        outS.println("0");
                        return;
                    }
                }
            } catch(IOException e) {
                System.out.println(e);
            } catch (Exception e) {
                System.out.println(e);
            }
        }   
    }

    public static void main(String[] args) {
        //Allows the user to control the number of consumer threads
        Scanner keyboard = new Scanner(System.in);
        System.out.print("Enter number of consumers: ");
        int numConsumers = keyboard.nextInt();

        System.out.print("Enter how long (seconds) to run: ");
        int time = keyboard.nextInt();

        System.out.println("Client ready! Continue when server ready.");
        System.out.print("Type \"abort\" and press \"Enter\" to stop "
                + "immediately or type anything else to continue: ");
        String cmd = keyboard.next();

        if(!cmd.toLowerCase().equals("abort")) {
            try {
                System.out.println("Acquiring host...");
                host = InetAddress.getLocalHost();
                System.out.println("Connecting to server...");
                link = new Socket(host,PORT);
                System.out.println("Connection found.");
                inS = new BufferedReader(new InputStreamReader(
                        link.getInputStream()));
                outS = new PrintWriter(link.getOutputStream(),true);
            } catch(UnknownHostException e) {
                System.out.println(e);
                System.exit(1);
            } catch(IOException e) {
                System.out.println(e);
            }
            System.out.println("Connection established: " + host + ": "
                    + PORT);

            Consumer c = new Consumer();

            for (int i = 0; i < numConsumers; i++) {
                new Thread(c).start();
                System.out.println("Consumer " + (i+1) + " starts...");
            }

            try {
                Thread.sleep(time*1000);
            } catch(Exception e) {
                System.out.println(e);
            }
            System.out.println("Time out.");
        }

        done = true;
        System.out.println("Client shutting down.");
    }
}

And here's the server code:

import java.util.*;
import java.io.*;
import java.util.concurrent.*;
import java.net.*;

public class ProducerServer {
    private static ServerSocket servSock;
    private static final int PORT = 4545;
    protected static boolean done = false;

    private static BufferedReader inS;
    private static PrintWriter outS;
    private static Socket link;

    static class Producer implements Runnable {
        protected BlockingQueue queue;
        Random random = new Random();

        Producer(BlockingQueue q) {
            queue = q;
        }

        @Override
        public void run() {
            try {
                while (true) {
                    Object justProduced = new Object();
                    queue.put(justProduced);
                    System.out.println("Object produced; List size is "
                            + queue.size());
                    if(done) {
                        System.out.println("Producer done.");
                        return;
                    }
                }
            }
            catch (InterruptedException e) {
                System.out.println(e);
            }           
        }
    }

    static class Manipulator implements Runnable {
        protected BlockingQueue queue;

        Manipulator(BlockingQueue q) {
            queue = q;
        }
        @Override
        public void run() {
            try {
                String request = inS.readLine();
                while(true) {
                    if(request.equals("0")) {Thread.sleep(100);}
                    if(request.equals("1")) {
                        Object obj = queue.take();
                        int len = queue.size();
                        System.out.println("Object taken; list size is " + len);
                        System.out.println("Sending object: " + obj);
                        outS.println(obj);
                    }
                    request = inS.readLine();
                    if(done){
                        System.out.println("Manipulator done.");
                        return;
                    }
                }
            } catch(Exception e) {
                System.out.println(e);
            }
        }       
    }


    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);
        System.out.print("Enter number of producers: ");
        int numProducers = keyboard.nextInt();

        System.out.print("Enter how long (seconds) to run: ");
        int time = keyboard.nextInt();

        System.out.println("Server ready! Continue when client ready.");
        System.out.print("Type \"abort\" and press \"Enter\" to stop "
                + "immediately or type anything else to continue: ");
        String cmd = keyboard.next();

        if(!cmd.toLowerCase().equals("abort")) {
            try {
                System.out.println("Opening port...");
                servSock = new ServerSocket(PORT);
                System.out.println("Awaiting client connection...");
                link = servSock.accept();
                System.out.println("New client found.\n");
                inS = new BufferedReader(new InputStreamReader(
                        link.getInputStream()));
                outS = new PrintWriter(link.getOutputStream(), true);
            } catch(IOException e) {
                System.out.println(e);
                System.exit(1);
            }
            System.out.println("Connection established on port: " + PORT);

            BlockingQueue myQueue = new ArrayBlockingQueue(10);

            for (int i = 0; i < numProducers; i++)
                new Thread(new Producer(myQueue)).start();

            Manipulator m = new Manipulator(myQueue);
            m.run();

            try {
                Thread.sleep(time*1000);
            } catch(Exception e) {
                System.out.println(e);
            }
            System.out.println("Time out.");
        }

        done = true;
        System.out.println("Server shutting down.");
    }
}

I say the programs are mostly working already, but I just wanted to ask about this last error before I turn it in.

I've checked that the done variable (my exit flag) is accessible by all threads in the server program; as it is within the client. I've also made sure than the done variable gets set to true in main at the appropriate point toward the end.

Any thoughts on how I can solve this error?

Answer 1

Actually I managed to change the declaration of Manipulator into something directly called by another thread. That act solved my problem in itself. Sorry for the inconvenience to those already trying to solve my problem. The code's there for interested parties trying to learn this complicated problem.