Websocket實現前后台通信，demo小測試

　　新需求大概如下：用戶登錄系統，登錄成功之后建立websocket連接，實現通信

　　總體思路：前端不是我負責，只是簡單的做個功能，先實現登錄，把用戶標識存入HttpSeesion,再建立websocket連接，攔截器HandshakeInterceptor攔截請求，把用戶標識存入Map<String, Object> attributes，然后處理器handler處理各種操作。

/** 
 * @author wangqq 
 * @version 創建時間：2018年11月1日 下午2:59:21 
 * 實現WebSocketConfigure配置自己的socket鏈接
 */
@Configuration //用於定義配置類，可替換xml配置文件
@EnableWebSocket
@EnableWebMvc //啟動Spring MVC特性
public class WebsocketConfig implements WebSocketConfigurer {

    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        // TODO Auto-generated method stub
        registry.addHandler(handler(), "show").addInterceptors(interceptor()).setAllowedOrigins("*");
    }
    
    @Bean
    public WebSocketHandler handler(){
        return new Hanlder();
    }
    
    @Bean  
    public HandshakeInterceptor interceptor() {  
        return new HandshakeInterceptor();  
    }  

}

registry.addHandler第一個參數是處理器，自己可以寫，第二個參數是前后台建立鏈接的路徑，

addInterceptors 添加攔截，再握手之前之后，處理自己的業務

setAllowedOrigins 解決跨域，*代表不限，如果要指定域名則要http或者https開頭

/** 
 * @author wangqq 
 * @version 創建時間：2018年11月1日 下午3:06:36 
 * 類說明 
 */
public class Hanlder extends TextWebSocketHandler {
    private Logger logger = Logger.getLogger(Hanlder.class);
    private static final Map<Integer,WebSocketSession> hotels;
    
    static{
        hotels = new HashMap<Integer, WebSocketSession>();
    }

    @Override
    public void afterConnectionEstablished(WebSocketSession session)
            throws Exception {
        // TODO Auto-generated method stub
        Integer hotelid = IHelper.toInteger(session.getAttributes().get("hotelid"));
        logger.info("-----------------afterConnectionEstablished-----------------");
        if(null != hotelid){
            logger.info(String.format("酒店連接，id:%s", hotelid));
            hotels.put(hotelid, session);

            JSONObject json = new JSONObject();
            json.put("code","testMessage");
            session.sendMessage(new TextMessage(json.toString()));
        }
        
        //super.afterConnectionEstablished(session);
    }
    /**
     * js調用websocket.send時候，會調用該方法
     */
    @Override
    protected void handleTextMessage(WebSocketSession session,
            TextMessage message) throws Exception {
        // TODO Auto-generated method stub
        logger.info(String.format("收到酒店（id:%s）發來消息,消息詳情:%s", session.getAttributes().get("hotelid"),message.toString()));
        super.handleTextMessage(session, message);
        //這里可以給用戶發消息
        logger.info("執行Hanlder---------客戶端收到請求");
    }
    
    @Override
    public void afterConnectionClosed(WebSocketSession session,
            CloseStatus status) throws Exception {
        // TODO Auto-generated method stub
        Integer hotelid = IHelper.toInteger(session.getAttributes().get("hotelid"));
        logger.info(String.format("用戶退出，酒店id：%s", hotelid));
        hotels.remove(hotelid);
        super.afterConnectionClosed(session, status);
    }
    /**
     * 給單個用戶發消息
     * @param hotelid
     * @param message
     * @throws IOException
     */
    public void sendMessage(Integer hotelid,TextMessage message) throws Exception{
        if(hotels.containsKey(hotelid)){
            if(hotels.get(hotelid).isOpen()){
                hotels.get(hotelid).sendMessage(message);
            }
        }
        
    }
    /**
     * 給所有在線用戶發消息
     * @param message
     * @throws IOException
     */
    public void sendMessage(TextMessage message) throws Exception{
        for(Integer id : hotels.keySet()){
            WebSocketSession session = hotels.get(id);
            if(session.isOpen()){
                session.sendMessage(message);
            }
        }
    }
    /**
     * 多個在線用戶，不同消息
     * @param data
     * @throws Exception
     */
    public void sendMessage(Map<Integer, TextMessage> data) throws Exception{
        for(Map.Entry<Integer, TextMessage> entry : data.entrySet()){
            Integer hotelid = entry.getKey();
            this.sendMessage(hotelid, entry.getValue());
        }
    }
    /**
     * 多個用戶，同一消息
     * @param hotelids
     * @param message
     * @throws Exception
     */
    public void sendMessage(List<Integer> hotelids,TextMessage message) throws Exception{
        for(Integer id : hotelids){
            this.sendMessage(id, message);
        }
    }
}

/** 
 * @author wangqq 
 * @version 創建時間：2018年11月2日 下午1:42:00 
 * 類說明 
 */
public class HandshakeInterceptor extends HttpSessionHandshakeInterceptor {
    
    private Logger logger = Logger.getLogger(HandshakeInterceptor.class);
    
    @Override
    public boolean beforeHandshake(ServerHttpRequest request,
            ServerHttpResponse response, WebSocketHandler wsHandler,
            Map<String, Object> attributes) throws Exception {
        // TODO Auto-generated method stub
        logger.info("-----------beforeHandshake---------");
        if(request instanceof ServletServerHttpRequest){
            ServletServerHttpRequest serverHttpRequest = (ServletServerHttpRequest)request;
            HttpSession session = serverHttpRequest.getServletRequest().getSession();
            if(null != session){
                logger.info("攔截請求，存入attribute,酒店id:"+session.getAttribute("hotelid"));
                if(null!=session.getAttribute("hotelid")){
                    attributes.put("hotelid", session.getAttribute("hotelid"));
                }
            }
        }
        return super.beforeHandshake(request, response, wsHandler, attributes);
    }
    
    @Override
    public void afterHandshake(ServerHttpRequest request,
            ServerHttpResponse response, WebSocketHandler wsHandler,
            Exception ex) {
        // TODO Auto-generated method stub
        logger.info("-----------afterHandshake--------------");
        super.afterHandshake(request, response, wsHandler, ex);
    }
}

 

前端頁面（簡單的不能再簡單，沒有考慮瀏覽器支不支持）

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'index.jsp' starting page</title>
    
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">    
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css">
    -->
    <script language="JavaScript" src="jquery/jquery-1.11.3.min.js" charset="UTF-8"></script>
    <script type="text/javascript">
        var ws = 
        $(function(){
            $.ajaxSettings.async=false;
            $.post('<%=basePath%>/show/doSaveSession',{'hotelid':1},function(data){
                console.log("執行保存session");//模擬先登錄
            });
            $.ajaxSettings.async=true;
            ws = new WebSocket("ws://localhost:7001/show");
            
           ws.onopen = function () {
              console.log("建立鏈接");
            
           }
           ws.onclose = function () {
              console.log("onclose");
           }
     
           ws.onmessage = function (msg) {
                   console.log("----------------");
                console.log(msg.data);
           }
        });
        
    </script>

  </head>
  
  <body>
    This is my JSP page. <br>

  </body>
</html>

 

執行結果：

前台

 

后台：

 

 

ps:2018-11-19 更新，后來測試一下，不用提前登陸，直接在前端連socket的路徑上面加參數，而后在攔截器的

beforeHandshake中就可把連接的用戶存入map