准备

导入依赖

 compile group: 'org.springframework', name: 'spring-messaging', version: '4.3.3.RELEASE'
 compile group: 'org.springframework', name: 'spring-websocket', version: '4.3.3.RELEASE'

方式一

<bean id="websocket" class="net.rock.projects.orp.web.websocket.WebsocketEndPoint" />
<websocket:handlers allowed-origins="*">  
    <websocket:mapping path="/websocket" handler="websocket"/>  
    <websocket:handshake-interceptors>  
    <bean class="com.up.websocket.HandshakeInterceptor"/>  
    </websocket:handshake-interceptors>  
</websocket:handlers>  

其中，path对应的路径就是前段通过ws协议调的接口路径
创建握手接口（拦截器）

public class HandshakeInterceptor extends HttpSessionHandshakeInterceptor {
    @Override
    public boolean beforeHandshake(ServerHttpRequest request,
                                   ServerHttpResponse response, WebSocketHandler wsHandler,
                                   Map<String, Object> attributes) throws Exception {

        HttpServletRequest servletRequest = ((ServletServerHttpRequest) request).getServletRequest();
        HttpSession session = servletRequest.getSession(false);
        User user = (User) session.getAttribute("token");

        if(user!=null){
            attributes.put("token", user);
        }
        return super.beforeHandshake(request, response, wsHandler, attributes);
    }

    @Override
    public void afterHandshake(ServerHttpRequest request,
                               ServerHttpResponse response, WebSocketHandler wsHandler,
                               Exception ex) {
        super.afterHandshake(request, response, wsHandler, ex);
    }
}

创建处理类

@Component
public class WebsocketEndPoint extends TextWebSocketHandler {

    @Autowired
    IProjectDeliverService iProjectDeliverService;
    @Autowired
    IProjectDeliverReplyService iProjectDeliverReplyService;
    @Autowired
    private IUserService iUserService;

    /**
     * 所有的用户
     */
    private static final Map<Integer , WebSocketSession > users ;

    static{
        users = new HashMap<>();
    }

    @Override
    protected void handleTextMessage(WebSocketSession session,
                                     TextMessage message) throws Exception {

        super.handleTextMessage(session, message);
        session.sendMessage(message);
    }
    @Override
    public void afterConnectionEstablished(final WebSocketSession session) throws Exception {

        User user = (User) session.getAttributes().get("token");
        if(user != null)
            users.put(user.getId() , session);
    }

    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {

        User user = (User) session.getAttributes().get("token");

        // 如果用户对象还存在内存中,那么不进行退出记录
        if(user != null){
            iUserService.exit(DateUtils.dateToString(new Date()),user.getId());
            System.out.println(user.getNickName()+" exits from the system ! Connection Closed！");
        }
    }


    /**
     * 发送给指定用户
     * @param userIds    用户编号数组,不传(长度=0) 默认发送给所有用户
     * @param message   消息内容
     */
    public static void sendToUser( TextMessage message , List<Integer> userIds){
        try {
            // 如果没有传用户编号 , 默认发送给所有用户
            if(userIds == null || userIds.size() == 0){
                if(users.keySet() != null && users.keySet().size() > 0 ){
                    for (Integer key : users.keySet()) {
                        if(users.get(key).isOpen())
                            users.get(key).sendMessage(message);
                    }
                }
            }else{  // 发送给指定的用户

                for (Integer id : userIds) {
                    if(users.containsKey(id) && users.get(id).isOpen()){
                        users.get(id).sendMessage(message);
                    }
                }

            }
        }catch (IOException e){
            e.printStackTrace();
        }
    }
}

用户页面连接(sockjs-0.3.min.js自行下载)

<script src="<%=resourcePath%>js/sockjs-0.3.min.js"></script>
<script>
    var ws = null;
    var url = "ws://<%=basePath.replace("http://","")%>/msgcenter?uid=20125";

    function socketConnection(){
        if (!url) {
            alert('Select whether to use W3C WebSocket or SockJS');
            return;
        }

        ws = new WebSocket(url); //申请一个WebSocket对象

        ws.onopen = function () {
            console.info("连接已经打开。。。。。。");
        };
        ws.onmessage = function (event) {
            console.info("你接受到消息是："+event.data);
                }
            }
        };
        ws.onclose = function (event) {
            console.info("连接已经断开。。。。。" );
        };
    }
 $(function(){
        socketConnection();
    });
</script>

后台调用sendToUser给指定用户发送信息

.................................................................................................

方式二

websocket入口

@Configuration
@EnableWebMvc
@EnableWebSocket
public class WebSocketConfig extends WebMvcConfigurerAdapter implements WebSocketConfigurer {
    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        //setAllowedOrigins("*") 解决跨域问题
        registry.addHandler(systemWebSocketHandler(),"/webSocketServer").addInterceptors(new WebSocketHandshakeInterceptor()).setAllowedOrigins("*");

        registry.addHandler(systemWebSocketHandler(), "/sockjs/webSocketServer").addInterceptors(new WebSocketHandshakeInterceptor()).withSockJS();
    }

    @Bean
    public WebSocketHandler systemWebSocketHandler(){
        return new SystemWebSocketHandler();
    }

}

拦截器,beforeHandshake在调用handler前处理方法。常用在注册用户信息，绑定WebSocketSession，在handler里根据用户信息获取WebSocketSession发送消息。

public class WebSocketHandshakeInterceptor implements HandshakeInterceptor {
    @Override
    public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Map<String, Object> attributes) throws Exception {


        if (request instanceof ServletServerHttpRequest) {
            ServletServerHttpRequest servletRequest = (ServletServerHttpRequest) request;
            HttpSession session = servletRequest.getServletRequest().getSession(false);
            if (session != null) {
                //使用userName区分WebSocketHandler，以便定向发送消息
                attributes.put("userId",session.getAttribute("userId"));
            }
        }
        return true;
    }

    @Override
    public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Exception exception) {

    }
}

handle处理器

public class SystemWebSocketHandler implements WebSocketHandler {

    private static final Map<String,WebSocketSession> users;

    static {
        users = new HashMap<>();
    }


    @Override
    public void afterConnectionEstablished(WebSocketSession session) throws Exception {

        String userId = (String) session.getAttributes().get("userId");
        if(userId !=null){
            users.put(userId,session);
        }
        session.sendMessage(new TextMessage("hello world"));
        System.out.println("建立连接");
    }

    @Override
    public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {

    }

    @Override
    public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
        System.out.println("连接被关闭");
        for (Map.Entry<String, WebSocketSession> entry : users.entrySet()) {
            if(entry.getValue().equals(session)){
                users.remove(entry.getKey());
            }
        }
    }

    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
        System.out.println("连接被关闭");
        users.remove(session);
    }

    @Override
    public boolean supportsPartialMessages() {
        return false;
    }

    /**
     * 给某个用户发送消息
     *
     * @param userId
     * @param message
     */
    public static void  sendMessageToUser(String userId, TextMessage message) throws IOException {
        Set<Map.Entry<String, WebSocketSession>> entries = users.entrySet();
        for (Map.Entry<String, WebSocketSession> entry : entries) {
            if(entry.getKey().equals(userId))
                entry.getValue().sendMessage(message);
        }
    }
}

用户建立socket连接(sockjs-0.3.min.js自行下载)

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%
  String path = request.getContextPath();
  String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path;
  String url = request.getServerName()+":"+request.getServerPort()+path;
%>
<html>
  <head>
    <title>index</title>
  </head>
  <body>
    <h3 align="center">
      消息通知：<span id="msg"></span>
    </h3>
  </body>
</html>
<script src="<%=basePath%>/js/jquery-1.9.1.min.js"></script>
<script src="<%=basePath%>/js/sockjs-0.3.min.js"></script>
<script>
    var websocket;
    if ('WebSocket' in window) {
        websocket = new WebSocket("ws://<%=url%>/webSocketServer?userId=1");
    } else if ('MozWebSocket' in window) {
        websocket = new MozWebSocket("ws://<%=url%>/webSocketServer?userId=1");
    } else {
        websocket = new SockJS("http://<%=url%>/sockjs/webSocketServer?userId=1");
    }
    websocket.onopen = function (evnt) {
        console.info("连接已建立")
    };
    websocket.onmessage = function (evnt) {
        console.info("本次推送内容是："+evnt.data);
        $("#msg").html(evnt.data)
    };
    websocket.onerror = function (evnt) {
        console.info("连接已断开")
    };
    websocket.onclose = function (evnt) {
        console.info("连接已断开")
    }

</script>

调用 sendMessageToUser推送信息

/**
     * 消息推送
     * @param msg  消息内容
     * @param userId 推送用户id
     */
    @RequestMapping(value = "pushMsg",method = RequestMethod.POST)
    @ResponseBody
    public String pushMsg(String userId, String msg) {
        System.out.println("用户id:"+userId+"    推送的消息："+msg);
        try {
            SystemWebSocketHandler.sendMessageToUser(userId,new TextMessage(msg));
            return new Gson().toJson("success");
        } catch (Exception e) {
            System.out.println(e.getMessage()+"................");
            e.printStackTrace();
            return new Gson().toJson("fail:"+e);
        }
    }

相关链接
http://www.bridgeli.cn/archives/262
https://my.oschina.net/ldl123292/blog/304360
http://www.cnblogs.com/nosqlcoco/p/5860730.html