Java里socket连接怎样进行心跳检测

在Java中，可以使用Socket连接进行心跳检测。心跳检测的主要目的是检测对方是否在线，通过定期发送小数据包来确认连接是否有效。以下是一个简单的心跳检测示例：

1. 服务器端代码：

import java.io.*; import java.net.*; import java.util.concurrent.*;  public class Server {     public static void main(String[] args) throws IOException, InterruptedException {         int port = 12345;         ExecutorService executorService = Executors.newFixedThreadPool(10);          ServerSocket serverSocket = new ServerSocket(port);         System.out.println("Server started on port " + port);          while (true) {             Socket clientSocket = serverSocket.accept();             executorService.submit(() -> handleClient(clientSocket));         }     }      private static void handleClient(Socket clientSocket) {         try {             InputStream inputStream = clientSocket.getInputStream();             OutputStream outputStream = clientSocket.getOutputStream();              BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));             PrintWriter writer = new PrintWriter(outputStream, true);              String heartBeatMessage = "HEARTBEAT";             ScheduledExecutorService heartbeatExecutor = Executors.newScheduledThreadPool(1);             heartbeatExecutor.scheduleAtFixedRate(() -> {                 try {                     writer.println(heartBeatMessage);                 } catch (IOException e) {                     System.out.println("Error sending heartbeat message: " + e.getMessage());                     break;                 }             }, 0, 30, TimeUnit.SECONDS); // 每30秒发送一次心跳检测              String inputLine;             while ((inputLine = reader.readLine()) != null) {                 System.out.println("Received message from client: " + inputLine);                 if (inputLine.equals("BYE")) {                     break;                 }             }              heartbeatExecutor.shutdown();             clientSocket.close();         } catch (IOException e) {             System.out.println("Error handling client: " + e.getMessage());         }     } } 

2. 客户端代码：

import java.io.*; import java.net.*; import java.util.concurrent.*;  public class Client {     public static void main(String[] args) throws IOException, InterruptedException {         String serverAddress = "localhost";         int port = 12345;          Socket socket = new Socket(serverAddress, port);         System.out.println("Connected to server");          InputStream inputStream = socket.getInputStream();         OutputStream outputStream = socket.getOutputStream();          BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));         PrintWriter writer = new PrintWriter(outputStream, true);          String heartBeatMessage = "HEARTBEAT";         ScheduledExecutorService heartbeatExecutor = Executors.newScheduledThreadPool(1);         heartbeatExecutor.scheduleAtFixedRate(() -> {             try {                 writer.println(heartBeatMessage);             } catch (IOException e) {                 System.out.println("Error sending heartbeat message: " + e.getMessage());                 break;             }         }, 0, 30, TimeUnit.SECONDS); // 每30秒发送一次心跳检测          String inputLine;         while ((inputLine = reader.readLine()) != null) {             System.out.println("Received message from server: " + inputLine);             if (inputLine.equals("BYE")) {                 break;             }         }          heartbeatExecutor.shutdown();         socket.close();     } } 

在这个示例中，服务器和客户端都定期发送心跳检测消息（“HEARTBEAT”），以确认连接是否有效。如果一方在指定的时间内没有收到心跳检测消息，它会认为连接已经断开，并采取相应的措施。