如何在没有错误的情况下停止服务器关闭套接字jav

如何解决如何在没有错误的情况下停止服务器关闭套接字jav

我制作了一个允许加入许多客户端的服务器。 但是我有一个问题。 我添加了应该启动/停止服务器的启动/停止按钮。但是代码不像我想要的那样工作：

private void btnssActionPerformed(java.awt.event.ActionEvent evt) {                                      
    // btnss == botton start stop
    if (btnss.getText().equals("START")) {
        exit = false;
        start();
        btnss.setText("STOP");
    } else {
        addToLogs("Chat server has been stopped");
        exit = true;
        btnss.setText("START");
        try {
            stop();
        } catch (IOException ex) {
            Logger.getLogger(ServerGui.class.getName()).log(Level.SEVERE,null,ex);
        }
    }
}

public static void start() {
new Thread(new ServerHandler()).start();
}
public static void stop() throws IOException {
if (!serverSocket.isClosed()){
        serverSocket.close();
    }
}

private static class ServerHandler implements Runnable {

    @Override
    public void run() {
        try {
            serverSocket = new ServerSocket(PORT);
            addToLogs("Server started on port: " + PORT);
            addToLogs("Now waiting for connections");
            while (!exit) {
                if (connectedClients.size() <= MAX_CONNECTED) {
                    new Thread(new ClientHandler(serverSocket.accept())).start();
                }
            }
        } catch (Exception e) {
            addToLogs("\nError has been occured \n");
    addToLogs(Arrays.toString(e.getStackTrace()));
    addToLogs("\nExiting");
        }
    }
}



private static class ClientHandler implements Runnable {

    private Socket clientSocket;
    private PrintWriter outPutToClient;
    private BufferedReader inputFromClient;
    private String name;

    public ClientHandler(Socket clientSocket) {
        this.clientSocket = clientSocket;
    }

    @Override
    public void run() {
        addToLogs("Client connected: " + clientSocket.getInetAddress());
        try {
            inputFromClient = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
            outPutToClient = new PrintWriter(clientSocket.getOutputStream(),true);
            for (;;) {
                name = inputFromClient.readLine();
                if (name == null) {
                    return;
                }
                synchronized (connectedClients) {
                    if (!name.isEmpty() && !connectedClients.keySet().contains(name)) {
                        break;
                    } else {
                        outPutToClient.println("INVALID OR USED NAME");
                    }
                }
            }
            outPutToClient.println("Welcome to the chat group," + name.toUpperCase() + "!");
            addToLogs(name.toUpperCase() + " has joined.");
            //function that save messagses
            addToLogs2(name);
            broadcastMessage("[SYSTEM] " + name.toUpperCase() + " has joined.");
            connectedClients.put(name,outPutToClient);
            String message;
            outPutToClient.println("You may join the chat now...");
            while ((message = inputFromClient.readLine()) != null && !exit) {
                if (!message.isEmpty()) {
                    if (message.toLowerCase().equals("/quit")) {
                        break;
                    }
                    broadcastMessage(String.format("[%s] %s",name,message));
                    // fauction of adds msgs
                }
            }
        } catch (Exception e) {
            addToLogs(e.getMessage());
        } finally {
            if (name != null) {
                addToLogs(name + " is leaving");
                connectedClients.remove(name);
                broadcastMessage(name + " has left");
            }
        }
    }
}

所以我得到了这些错误：

[java.net.DualStackPlainSocketImpl.accept0(Native Method),java.net.DualStackPlainSocketImpl.socketAccept(DualStackPlainSocketImpl.java:131),java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:404),java.net.PlainSocketImpl.accept(PlainSocketImpl.java:199),java.net.ServerSocket.implAccept(ServerSocket.java:545),java.net.ServerSocket.accept(ServerSocket.java:513),server.ServerGui$ServerHandler.run(ServerGui.java:312),java.lang.Thread.run(Thread.java:745)]