java实现websocket连接，包含获取httpSession

1、开发环境eclipse、tomcat7、jdk1.7

2、pom jar包引用

    

	<dependency>
	     <groupId>javax</groupId>
	     <artifactId>javaee-api</artifactId>
	     <version>7.0</version>
	     <scope>provided</scope>
	</dependency>

3、服务端

   

@ServerEndpoint(value = "/websocket", configurator = GetHttpSessionConfigurator.class)
public class SessionStatusWebSocket {

	private static int onlineCount = 0;
	// concurrent包的线程安全Set，用来存放每个客户端对应的webSocketSet对象。若要实现服务端与单一客户端通信的话，可以使用Map来存放，其中Key可以为用户标识
	private static CopyOnWriteArraySet<SessionStatusWebSocket> webSocketSet = new CopyOnWriteArraySet<SessionStatusWebSocket>();
	// 一个会话可能造成
	private static Map<String, HttpSession> socketNumb = new ConcurrentHashMap<String, HttpSession>();
	// 与某个客户端的连接会话，需要通过它来给客户端发送数据
	private Session session;
	// 整个会话
	private HttpSession httpSession;

	/**
	 * 连接建立成功调用的方法
	 * 
	 * @param session
	 *            可选的参数。session为与某个客户端的连接会话，需要通过它来给客户端发送数据
	 */
	@OnOpen
	public void onOpen(Session session, EndpointConfig config) {
		this.session = session;
		this.httpSession = (HttpSession) config.getUserProperties().get(HttpSession.class.getName());
		webSocketSet.add(this); // 加入set中
		addOnlineCount(); // 连接数+1
		System.out.println("有新连接加入！当前连接数为：" + getOnlineCount());
	}

	/**
	 * 连接关闭调用的方法
	 */
	@OnClose
	public void onClose() {
		webSocketSet.remove(this); // 从set中删除
		subOnlineCount(); // 在线数减1
		System.out.println("有一连接关闭！当前连接数为：" + getOnlineCount());
	}

	/**
	 * 收到客户端消息后调用的方法
	 * 
	 * @param message
	 *            客户端发送过来的消息
	 * @param session
	 *            可选的参数
	 */
	@OnMessage
	public void onMessage(String message, Session session) {
		try {
			sendMessage(message);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	/**
	 * 发生错误时调用
	 * 
	 * @param session
	 * @param error
	 */
	@OnError
	public void onError(Session session, Throwable error) {
		System.out.println("发生错误");
		error.printStackTrace();
	}

	public void sendMessage(String message) throws IOException {
		// 查询用户是否过期
		String sessionToken = (String) httpSession.getAttribute("sid");
		if (sessionToken != null) {
			Integer userId = UmDBManager.webSocketCheckUserSessionToken(sessionToken);
			if (userId == null) {
				message = "0";// 用户正常退出
			} else if (userId == 0) {
				message = "1";// 该用户在其他地方登入
			}
		} else {
			message = "2";// 服务器重启httpsession更改，但是客户端sid还在
		}
		this.session.getBasicRemote().sendText(message);
	}

	public static synchronized int getOnlineCount() {
		return onlineCount;
	}

	public static synchronized void addOnlineCount() {
		onlineCount = SessionStatusWebSocket.getOnlineCount();
		onlineCount++;
	}

	public static synchronized void subOnlineCount() {
		onlineCount = SessionStatusWebSocket.getOnlineCount();
		onlineCount--;
	}
}

4、GetHttpSessionConfigurator配置类获取httpsession

import javax.servlet.http.HttpSession;
import javax.websocket.HandshakeResponse;
import javax.websocket.server.HandshakeRequest;
import javax.websocket.server.ServerEndpointConfig;
import javax.websocket.server.ServerEndpointConfig.Configurator;

public class GetHttpSessionConfigurator extends Configurator {

	@Override
	public void modifyHandshake(ServerEndpointConfig sec, HandshakeRequest request, HandshakeResponse response) {
		HttpSession httpSession = (HttpSession) request.getHttpSession();
		sec.getUserProperties().put(HttpSession.class.getName(), httpSession);
	}
}

5、此时httpsession为null，需要配置拦截器在容器初始化时获取httpsession

import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.http.HttpServletRequest;

public class RequestListener implements ServletRequestListener {

	@Override
	public void requestDestroyed(ServletRequestEvent sre) {

	}

	public RequestListener() {

	}

	@Override
	public void requestInitialized(ServletRequestEvent sre) {
		// 将所有request请求都携带上httpSession
		((HttpServletRequest) sre.getServletRequest()).getSession();
	}

}

6、web监听器配置

	<!--HttpSessionListener 监听器-->
	<listener>
	    <listener-class>包路径.RequestListener</listener-class>
	</listener>

7、前端连接测试

//读取配置文件获取webSocketurl
        	var wswebsocketUrl = data.webSocketUrl;
            var websocket = null;
            //判断当前浏览器是否支持WebSocket
            if ('WebSocket' in window) {
            	console.log(wswebsocketUrl);
                websocket = new WebSocket("ws://" + wswebsocketUrl);
            }
            else {
                alert('当前浏览器 Not support websocket')
            }  

            //连接发生错误的回调方法
            websocket.onerror = function () {
                setMessageInnerHTML("WebSocket连接发生错误");
            };

            //连接成功建立的回调方法
            websocket.onopen = function () {
                setMessageInnerHTML("WebSocket连接成功");
            }

            //接收到消息的回调方法
            websocket.onmessage = function (event) {
            	var msg = event.data;
            	//业务处理逻辑
                setMessageInnerHTML(event.data);
            }

            //连接关闭的回调方法
            websocket.onclose = function () {
                setMessageInnerHTML("WebSocket连接关闭");
                window.clearInterval(timer);
            }

            //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
            window.onbeforeunload = function () {
                closeWebSocket();
            }

            //将消息显示在网页上
            function setMessageInnerHTML(innerHTML) {
              // console.log(innerHTML);
            }

            //关闭WebSocket连接
            function closeWebSocket() {
                websocket.close();
            }

            //发送消息
            function send() {
            	//var sid = $.cookie('sid'); //后台将httpOnly设置为false
                websocket.send("登入状态");
            }
            
            var timer = setInterval(send, 1000);