springboot SocketServer向客户端发送数据 demo

以下是一个基本的 Spring Boot SocketServer 向客户端发送数据的 Demo:

1. 首先，需要定义一个 SocketServer 类:

@Component
public class MySocketServer {
    
    private ServerSocket serverSocket;
    
    @Value("${mysocketserver.port}")
    private int port;

    @PostConstruct
    public void init() {
        try {
            serverSocket = new ServerSocket(port);
            System.out.println("SocketServer started on port " + port);
            while (true) {
                Socket clientSocket = serverSocket.accept();
                System.out.println("New client connected: " + clientSocket.getInetAddress().getHostAddress());
                handleClient(clientSocket);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void handleClient(Socket clientSocket) {
        try {
            BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
            PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
            String inputLine;
            while ((inputLine = in.readLine()) != null) {
                System.out.println("Received message from client: " + inputLine);
                out.println("Server received message: " + inputLine);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    @PreDestroy
    public void destroy() {
        try {
            serverSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

2. 在 application.properties 中定义 SocketServer 的端口:

mysocketserver.port=8080

3. 在另一个类中，可以使用 Spring 的 Autowired 注解来注入 MySocketServer 实例，并调用 sendToClient 方法向客户端发送消息:

@Service
public class MyService {

    @Autowired
    private MySocketServer socketServer;

    public void sendToClient(Socket clientSocket, String message) {
        try {
            PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
            out.println(message);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

这样就可以在 MyService 中调用 sendToClient 方法向客户端发送消息了。