SpringBoot实现WebSocket服务端

WebSocket 可以让你实现 实时通信 ，比普通 HTTP 接口更炫也更"活"。今天讲一个 Spring Boot + Java 的实现思路。

1️⃣ 添加依赖

Maven:

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<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-websocket</artifactId>
</dependency>

2️⃣ 创建 WebSocket 配置

Java 版本：

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import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;

@Configuration
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {

    private final MyWebSocketHandler handler;

    public WebSocketConfig(MyWebSocketHandler handler) {
        this.handler = handler;
    }

    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        registry.addHandler(handler, "/ws").setAllowedOrigins("*");
    }
}

/ws 就是前端连接的 WebSocket 地址
setAllowedOrigins("*") 可以解决跨域问题（开发阶段）

3️⃣ 创建 WebSocket 处理器

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import org.springframework.stereotype.Component;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

@Component
public class MyWebSocketHandler extends TextWebSocketHandler {

    private final Set<WebSocketSession> sessions = Collections.synchronizedSet(new HashSet<>());

    @Override
    public void afterConnectionEstablished(WebSocketSession session) {
        sessions.add(session);
        System.out.println("新连接: " + session.getId());
    }

    @Override
    protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
        System.out.println("收到消息: " + message.getPayload());

        // 广播给所有连接
        synchronized (sessions) {
            for (WebSocketSession s : sessions) {
                if (s.isOpen()) {
                    s.sendMessage(new TextMessage("收到消息: " + message.getPayload()));
                }
            }
        }
    }

    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus status) {
        sessions.remove(session);
        System.out.println("连接关闭: " + session.getId());
    }
}

4️⃣ postman测试

ws://localhost:8081/ws