springboot如何建立websocket连接

Spring Boot提供了一种简单的方式来集成WebSocket支持，主要通过WebFlux框架实现。以下是构建WebSocket连接的基本步骤：

1. 添加依赖：在`pom.xml`文件中添加WebSocket相关的Spring Boot starter依赖，例如：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-webflux</artifactId>
</dependency>
<dependency>
    <groupId>org.webjars</groupId>
    <artifactId>webjars-locator-core</artifactId>
</dependency>

2. 配置WebSocket：在Spring Boot应用中，你需要配置一个WebSocketEndpoint，这通常是一个实现了`ServerWebsocketHandler`接口的类。例如：

import org.springframework.context.annotation.Bean;
import org.springframework.messaging.handler.annotation.MessageMapping;
import org.springframework.messaging.simp.config.SimpMessagingTemplate;
import org.springframework.stereotype.Component;

@Component
public class ChatWebSocket {

    @MessageMapping("/chat")
    public void handleText(String message) {
        // 处理接收到的消息
    }

    @Bean
    public ServerWebSocketHandler webSocketHandler() {
        return new ChatWebSocket();
    }
}

3. 注册WebSocket处理器：在启动类上添加`@EnableWebSocketMessageBroker`注解，并指定前缀(`"/topic"`):

import org.springframework.context.annotation.Configuration;
import org.springframework.messaging.simp.config.MessageBrokerRegistry;
import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker;
import org.springframework.web.socket.config.annotation.StompEndpointRegistry;

@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig {

    @Override
    public void configureMessageBroker(MessageBrokerRegistry config) {
        config.enableSimpleBroker("/topic");
        config.setApplicationDestinationPrefixes("/app");
    }

    @Override
    public void registerStompEndpoints(StompEndpointRegistry registry) {
        registry.addEndpoint("/ws").withSockJS();
    }
}

4. 客户端连接：客户端可以使用WebSocket API（如JavaScript的WebSocket对象）来连接到服务器，比如使用SockJS和STOMP。