Java 中实现WebSocket

在Spring中实现WebSocket步骤

WebSocket 详细讲解请参考该静默虚空博客

第一步：使用Spring 引入Jar包

<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-websocket</artifactId>
    <version>1.4.0</version>
</dependency>

第二步：创建WebSocket处理器

扩展 TextWebSocketHandler或BinaryWebSocketHandler,Spring收到WebSocket事件时，会自动调用事件对应方法。

import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.TextMessage;

public class MyHandler extends TextWebSocketHandler {

    @Override
    public void handleTextMessage(WebSocketSession session, TextMessage message) {
        // ...
    }

}

WebSocketHandler 源码如下，这意味着你的处理器大概可以处理哪些 WebSocket 事件：

public interface WebSocketHandler {

   /**
    * 建立连接后触发的回调
    */
   void afterConnectionEstablished(WebSocketSession session) throws Exception;

   /**
    * 收到消息时触发的回调
    */
   void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception;

   /**
    * 传输消息出错时触发的回调
    */
   void handleTransportError(WebSocketSession session, Throwable exception) throws Exception;

   /**
    * 断开连接后触发的回调
    */
   void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception;

   /**
    * 是否处理分片消息
    */
   boolean supportsPartialMessages();

}

配置WebSocket

配置的两种方式：注解和xml。(其作用就是将WebSocket处理器添加到注册中心) 1.实现 WebSocketConfigurer

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 {

    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        registry.addHandler(myHandler(), "/myHandler");
    }

    @Bean
    public WebSocketHandler myHandler() {
        return new MyHandler();
    }

}

xml方式

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:websocket="http://www.springframework.org/schema/websocket"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/websocket
        http://www.springframework.org/schema/websocket/spring-websocket.xsd">

    <websocket:handlers>
        <websocket:mapping path="/myHandler" handler="myHandler"/>
    </websocket:handlers>

    <bean id="myHandler" class="org.springframework.samples.MyHandler"/>

</beans>