java - 我怎样才能安全地停止这个Java服务器程序？

Question

我想通过终端在我的ubuntu计算机中运行一个java服务器程序，但问题是一旦我启动该程序，我就无法停止它(该程序正在终端中运行并等待客户端)。

这是我的代码:

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

public class EchoServer2 extends Thread {
    protected Socket clientSocket;

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

        try {
            serverSocket = new ServerSocket(2000);
            System.out.println("Connection Socket Created");
            try {
                while (true) {
                    System.out.println("Waiting for Connection");
                    new EchoServer2(serverSocket.accept());
                }
            } catch (IOException e) {
                System.err.println("Accept failed.");
                System.exit(1);
            }
        } catch (IOException e) {
            System.err.println("Could not listen on port: 2000.");
            System.exit(1);
        } finally {
            try {
                serverSocket.close();
            } catch (IOException e) {
                System.err.println("Could not close port: 2000.");
                System.exit(1);
            }
        }
    }

    private EchoServer2(Socket clientSoc) {
        clientSocket = clientSoc;
        start();
    }

    public void run() {
        System.out.println("New Communication Thread Started");

        try {
            PrintWriter out = new PrintWriter(clientSocket.getOutputStream(),
                    true);
            BufferedReader in = new BufferedReader(
                    new InputStreamReader(clientSocket.getInputStream()));

            String inputLine;

            while ((inputLine = in.readLine()) != null) {
                System.out.println("Server: " + inputLine);
                out.println(inputLine);

                if (inputLine.equals("Bye."))
                    break;
            }

            out.close();
            in.close();
            clientSocket.close();
        } catch (IOException e) {
            System.err.println("Problem with Communication Server");
            System.exit(1);
        }
    }
}

我知道我可以终止该进程，但我不想强行停止该程序。我想知道:如何安全地停止该程序？我如何在我的代码中实现这一点？

Answer 1

让我们说清楚，您在客户端接受时阻塞主线程。这并不是彻底关闭程序的真正方法。

我的解决方案是运行一个单独的线程，它将完成接受工作。

为了说明这一点，这是我的代码:

<小时/>

这是接受线程:

private static Thread acception = new Thread("Acception Thread") {

    public void run() {

        try {
            while (true) {
                System.out.println("Waiting for Connection");
                new EchoServer2(serverSocket.accept());
            }
    ->  } catch (SocketException e) {
    ->      if(serverSocket.isClosed())
    ->          System.out.println("Connection Closed.");
    ->  }
        } catch (IOException e) {
            System.err.println("Accept failed.");
            System.exit(1);
        }

    }
};

<小时/>

这是修改后的 main 方法:

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


    try {
        serverSocket = new ServerSocket(2000);
        System.out.println("Connection Socket Created");
->      acception.start();
    } catch (IOException e) {
        System.err.println("Could not listen on port: 2000.");
        System.exit(1);
    }


    //support to close, using the command line.

    Scanner scn = new Scanner(System.in);
    String s = scn.next();

    while(true) {
        if("quit".equals.(s)) {
            try {
                serverSocket.close();
            } catch (IOException e) {
                System.err.println("Could not close port: 2000.");
                System.exit(1);
            } finally {
                break;
            }
        }
        s = scn.next();
    }
}