websocket+spring JAVA后端快速入门

websocket 是 Html5 新增加特性之一，目的是浏览器与服务端建立全双工的通信方式。

Handler处理类

一：实现 WebSocketHandler 接口

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public interface WebSocketHandler { void afterConnectionEstablished(WebSocketSession session) throws Exception; 
void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception;
 void handleTransportError(WebSocketSession session, Throwable exception) throws Exception; 
void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception; boolean supportsPartialMessages();}

二：扩展 AbstractWebSocketHandler

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@Servicepublic class ChatHandler extends AbstractWebSocketHandler { private static final Logger logger = LoggerFactory.getLogger(ChatHandler.class);
 private final static List<WebSocketSession> sessions = Collections.synchronizedList(new ArrayList<WebSocketSession>()); 
// handle text msg. @Override protected void handleTextMessage(WebSocketSession session, TextMessage message) 
throws Exception { session.sendMessage(new TextMessage("hello world.")); }}

还可以重载其他三个方法：

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handleBinaryMessage()handlePongMessage()handleTextMessage()

三：扩展 TextWebSocketHandler

还可以重载afterConnectionEstablished() and afterConnectionClosed()方法:

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// 当新连接建立的时候，被调用;public void afterConnectionEstablished(WebSocketSession session) throws Exception { #("Connection established");
 #("getId:" + session.getId()); # ("getLocalAddress:" + session.getLocalAddress().toString());
 # ("getUri:" + session.getUri().toString());}// 当连接关闭时被调用;@Overridepublic void afterConnectionClosed(WebSocketSession session,
 CloseStatus status) throws Exception { #("Connection closed. Status: " + status);}

四： 拦截器实现

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package com.websocket;@Service//如果采用WebSocketConfig类配置，需加上这一行;
采用XML配置则不用public class WebSocketHandshakeInterceptor implements HandshakeInterceptor {@Overridepublic boolean beforeHandshake(ServerHttpRequest request,
 ServerHttpResponse response, WebSocketHandler wsHandler, 
Map<String, Object> attributes) throws Exception {if (request instanceof ServletServerHttpRequest) {attributes.put("username",userName);
}return true;}@Overridepublic void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Exception exception) {}}

五： springMVC配置

方法一：编写 WebSocketConfig 配置类，实现 WebSocketConfigurer 接口。

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@Configuration@EnableWebSocketpublic class WebSocketConfig implements WebSocketConfigurer{ @Autowired private ChatHandler chatHandler;
 @Autowired private WebSocketHandshakeInterceptor webSocketHandshakeInterceptor;
 @Override public void registerWebSocketHandlers(WebSocketHandlerRegistry registry)
 { registry.addHandler(chatHandler,"/chat").addInterceptors(webSocketHandshakeInterceptor); }}

六：通过 XML 配置文件添加配置

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<bean id="chatHandler" class="com.websocket.ChatHandler"/><websocket:handlers><!-- 配置消息处理bean和路径的映射关系
 --><websocket:mapping path="/chat" handler="chatHandler"/><!-- 配置握手拦截器 
--><websocket:handshake-interceptors><bean class="com.websocket.WebSocketHandshakeInterceptor"/></websocket:handshake-interceptors><!-- 开启sockjs，
去掉则关闭sockjs --><websocket:sockjs/></websocket:handlers><!-- 配置websocket消息的最大缓冲区长度，
可以不配 --><bean class="org.springframework.web.socket.server.standard.
ServletServerContainerFactoryBean"><property name="maxTextMessageBufferSize" value="8192"/><property name="maxBinaryMessageBufferSize" value="8192"/></bean>

七：controller实现

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import org.springframework.messaging.handler.annotation.
MessageMapping;import org.springframework.stereotype.Controller;import org.springframework.
beans.factory.annotation.Autowired;import org.springframework.messaging.simp.SimpMessagingTemplate;
import org.springframework.messaging.handler.annotation.DestinationVariable; import com.app.
deploying.model.Message;import com.spring.pojo.Greeting;import com.spring.pojo.HelloMessage;
@Controllerpublic class GreetingController { @Autowired private SimpMessagingTemplate simpMessagingTemplate;
 @MessageMapping("/room-message/{roomId}") public void roomMessage(Message message, @DestinationVariable String roomId)
{ String englishName = message.getTo(); String dest = "/message/" + roomId + "/" + englishName; LogConstant.runLog.
info(roomId+"号房间——"+"收到"+message.getFrom()+"发送至"+englishName+"的消息："+"\""+message.getContent()+"\"");
 message.setDate(new Timestamp(System.currentTimeMillis())); this.simpMessagingTemplate.convertAndSend(dest, message); }}

前端代码暂无