java - 客户端重新连接java套接字

Question

好吧，我需要编写一个能够检测客户端和服务器之间的连接的客户端...一旦服务器关闭并恢复我的客户端需要能够将其连接回服务器..但是我我真的不知道该怎么做...如果可能的话有什么帮助吗？

 public TEST(String serverIP, int serverPort){
    Log("Connection to the Server....");
    try{
        socket = new Socket(serverIP, serverPort);
        Log("Connected to the server : "+socket);
        start();
    } catch(UnknownHostException uhe){
        System.out.println("Unknown Host: "+ uhe.getMessage());
    } catch (IOException ioe){
        System.out.println("IO Exception: "+ioe.getMessage());
    }

    String readline = "";

    streamOutput.println("TRY test");

    while(true){
        try{
            readline = streamInput.readLine();
            System.out.println(readline);
        } catch (IOException ioe){
            System.out.println("Error in sending: "+ioe.getMessage());
            return;
        }
    }
}

上面是我的客户端代码，编译后用于连接到服务器...

Answer 1

了解连接已关闭的唯一方法是尝试通过线路发送数据。连接不会自动测试打开/关闭状态。如果您想检查关闭的连接并重新连接，则必须从一个连接到另一个连接发送心跳信号。通常，它只是一个特殊的字节或微小的消息，告诉对方“我还在这里”

但是，根据您的应用程序，您可能不需要它。您的应用程序的双方都会启动消息吗？或者它是一个 RMI 风格的应用程序？服务器在哪里只监听请求？

也许是这样的？

    class Client {
        private Socket socket;
        private boolean tryToReconnect = true;
        private final Thread heartbeatThread;
        private long heartbeatDelayMillis = 5000;

        public Client(final String server, final int port) {
            connect(server, port);
            heartbeatThread = new Thread() {
                public void run() {
                    while (tryToReconnect) {
                        //send a test signal
                        try {
                            socket.getOutputStream().write(666);
                            sleep(heartbeatDelayMillis);
                        } catch (InterruptedException e) {
                            // You may or may not want to stop the thread here
                            // tryToReconnect = false;
                        } catch (IOException e) {
                            logger.warn("Server is offline");
                            connect(server, port);
                        }
                    }
                };
            };
            heartbeatThread.start();
        }

        private void connect(String server, int port){
            try {
                socket = new Socket(server, port);
            } catch (UnknownHostException e) {
                logger.error(e, e);
            } catch (IOException e) {
                logger.error(e, e);
            }
        }

        public void shutdown() {
            tryToReconnect = false;
        }
    }