基于tomcat 7.0.68 的websocket 实现，及通过 HttpSessionId 实现websocket session 共享

Posted 2020-07-22 TT_DUL

0、先把页面调用代码贴出来好了

var historyWebsocket = null;
//  var websocketOnline = null;

      //判断当前浏览器是否支持WebSocket
    <%
        Properties props = PropUtils.getProps();
        String url=props.getProperty("webSocketIp");
    %>

    if(‘WebSocket‘ in window){
        historyWebsocket = new WebSocket("ws://<%=url%>/BGMS/historyWebsocket");
    }
    else{
        alert(‘Not support websocket‘)
    }

  //连接发生错误的回调方法
    historyWebsocket.onerror = function(){
        setMessageInnerhtml("error");
    };

    //连接成功建立的回调方法
    historyWebsocket.onopen = function(event){
        send();
    }
 //接收到消息的回调方法
    historyWebsocket.onmessage = function(event){

        var data = eval("("+event.data+")");//初始化数据
    }

    //连接关闭的回调方法
    historyWebsocket.onclose = function(){
        setMessageInnerHTML("close");
    }


    //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(){
        historyWebsocket.close();
    }

    //将消息显示在网页上
    function setMessageInnerHTML(innerHTML){
        $("#message").empty();
        document.getElementById(‘message‘).innerHTML +=‘<font color="#00CACA"class="message">‘ +innerHTML + ‘</font><br/>‘;
    }

    //关闭连接
    function closeWebSocket(){
        historyWebsocket.close();
    }
    //发送消息
    function send(){
//         var message = document.getElementById(‘text‘).value;
//         mesg="14701661345";

//          historyWebsocket.send(message);
    }

1、onlineWebsocket.java

import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArraySet;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import javax.websocket.EndpointConfig;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;





//该注解用来指定一个URI，客户端可以通过这个URI来连接到WebSocket。类似Servlet的注解mapping。无需在web.xml中配置。
@ServerEndpoint(value="/onlineWebsocket",configurator=GetHttpSessionConfigurator.class)
public class OnlineStateWebSocket {
    private static final Logger LOG = LoggerFactory.getLogger(OnlineStateWebSocket.class);

    //静态变量，用来记录当前在线连接数。应该把它设计成线程安全的。
    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MyWebSocket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<OnlineStateWebSocket> webSocketSet = new CopyOnWriteArraySet<OnlineStateWebSocket>();

    //用来存放 sim 卡号对应的 连接 session 的map  ,key 为sim 卡号,value 为各个终端的session 对象
    private static ConcurrentHashMap<String,ArrayList<OnlineStateWebSocket>> simSessionWebSocketMap = new ConcurrentHashMap<String,ArrayList<OnlineStateWebSocket>>();

    //用来存放 httpSessionId/session 的map  ,key 为httpSessionId ,value 为各个终端的session 对象
    private static ConcurrentHashMap<String,OnlineStateWebSocket> httpSessionWebSocketMap = new ConcurrentHashMap<String,OnlineStateWebSocket>();


    //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;

    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;
        webSocketSet.add(this);     //加入set中
        addOnlineCount();           //在线数加1

        this.httpSession = (HttpSession) config.getUserProperties()
                .get(HttpSession.class.getName());
        //用于共享 httpSession
        httpSessionWebSocketMap.put(this.httpSession.getId(), this);


        System.out.println("实时数据:有新连接加入！当前在线人数为" + 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    

        Set<Entry<String,ArrayList<OnlineStateWebSocket>>> entrySet = simSessionWebSocketMap.entrySet();

        Iterator<Entry<String, ArrayList<OnlineStateWebSocket>>> iterator = entrySet.iterator();
        while(iterator.hasNext()){

            Entry<String, ArrayList<OnlineStateWebSocket>> next = iterator.next();

            String key = next.getKey();    //获取sim卡号

            ArrayList<OnlineStateWebSocket> value = next.getValue(); //获取sim卡号对应的 连接的websocket终端

            if(value.contains(this)){
                if(value.size()>1){
                    value.remove(this);
                    simSessionWebSocketMap.replace(key, value);
                }else{
                    simSessionWebSocketMap.remove(key);
                }

            }
        }

        System.out.println("实时数据:有一连接关闭！当前在线人数为" + 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) {
        System.out.println("实时数据:来自客户端的消息:" + message);

        String[] SimArray = message.split(",");

        this.session = session;
        webSocketSet.add(this);     //加入set中

        for(String sim:SimArray){

             ArrayList<OnlineStateWebSocket> vehicleClientList ;

             if(simSessionWebSocketMap.get(sim.trim()) != null){
                vehicleClientList=simSessionWebSocketMap.get(sim.trim());   //取出当前sim 卡号所对应的所有session

                vehicleClientList.add(this);
                simSessionWebSocketMap.replace(sim.trim(), vehicleClientList);
             }else{
                vehicleClientList= new ArrayList<OnlineStateWebSocket>();
                vehicleClientList.add(this);

                 simSessionWebSocketMap.put(sim.trim(), vehicleClientList);
             }

        }

    }

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

    /**
     * 这个方法与上面几个方法不一样。没有用注解，是根据自己需要添加的方法。
     * @param message
     * @throws IOException
     */
    public   void sendMessage(String message,HttpServletRequest request) throws IOException{
        if(this.session.isOpen()){
            this.session.getBasicRemote().sendText(message);
            this.session.setMaxTextMessageBufferSize(102400);
//          this.session.getAsyncRemote().sendText(message);
        }

    }

    public   void sendMessage(String message) throws IOException{

        if(this.session.isOpen()){
            this.session.getBasicRemote().sendText(message);
            this.session.setMaxTextMessageBufferSize(102400);
//          this.session.getAsyncRemote().sendText(message);
        }
    }

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

    public static synchronized void addOnlineCount() {
        OnlineStateWebSocket.onlineCount++;
    }

    public static synchronized void subOnlineCount() {
        OnlineStateWebSocket.onlineCount--;
    }

    public static CopyOnWriteArraySet<OnlineStateWebSocket> getWebSocketSet() {
        return webSocketSet;
    }

    public static void setWebSocketSet(CopyOnWriteArraySet<OnlineStateWebSocket> webSocketSet) {
        OnlineStateWebSocket.webSocketSet = webSocketSet;
    }



}

2、RealWebsocket.java

import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArraySet;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import javax.websocket.EndpointConfig;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;





//该注解用来指定一个URI，客户端可以通过这个URI来连接到WebSocket。类似Servlet的注解mapping。无需在web.xml中配置。
@ServerEndpoint(value ="/realWebsocket",configurator=GetHttpSessionConfigurator.class)
public class RealWebSocket {
    private static final Logger LOG = LoggerFactory.getLogger(RealLocationWebSocket.class);


    //静态变量，用来记录当前在线连接数。应该把它设计成线程安全的。
    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MyWebSocket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<RealLocationWebSocket> webSocketSet = new CopyOnWriteArraySet<RealLocationWebSocket>();

    //用来存放 sim 卡号对应的 连接 session 的map  ,key 为sim 卡号,value 为各个终端的session 对象
    private static ConcurrentHashMap<String,ArrayList<RealLocationWebSocket>> simSessionWebSocketMap = new ConcurrentHashMap<String,ArrayList<RealLocationWebSocket>>();

    //用来存放 httpSessionId/session 的map  ,key 为httpSessionId ,value 为各个终端的session 对象
    private static ConcurrentHashMap<String,RealLocationWebSocket> httpSessionWebSocketMap = new ConcurrentHashMap<String,RealLocationWebSocket>();


    //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;

    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;
        webSocketSet.add(this);     //加入set中
        addOnlineCount();           //在线数加1


        this.httpSession = (HttpSession) config.getUserProperties()
                .get(HttpSession.class.getName());
        //用于共享 httpSession
        httpSessionWebSocketMap.put(this.httpSession.getId(), this);

        System.out.println("实时数据:有新连接加入！当前在线人数为" + 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    

        Set<Entry<String,ArrayList<RealLocationWebSocket>>> entrySet = simSessionWebSocketMap.entrySet();

        Iterator<Entry<String, ArrayList<RealLocationWebSocket>>> iterator = entrySet.iterator();
        while(iterator.hasNext()){

            Entry<String, ArrayList<RealLocationWebSocket>> next = iterator.next();

            String key = next.getKey();    //获取sim卡号

            ArrayList<RealLocationWebSocket> value = next.getValue(); //获取sim卡号对应的 连接的websocket终端

            if(value.contains(this)){
                if(value.size()>1){
                    value.remove(this);
                    simSessionWebSocketMap.replace(key, value);
                }else{
                    simSessionWebSocketMap.remove(key);
                }

            }
        }


        System.out.println("实时数据:有一连接关闭！当前在线人数为" + 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) {
        System.out.println("实时数据:来自客户端的消息:" + message);


        String[] SimArray = message.split(",");

        this.session = session;
        webSocketSet.add(this);     //加入set中

        for(String sim:SimArray){

             ArrayList<RealLocationWebSocket> vehicleClientList ;

             if(simSessionWebSocketMap.get(sim.trim()) != null){
                vehicleClientList=simSessionWebSocketMap.get(sim.trim());   //取出当前sim 卡号所对应的所有session
                vehicleClientList.add(this);
                simSessionWebSocketMap.replace(sim.trim(), vehicleClientList);
             }else{
                vehicleClientList= new ArrayList<RealLocationWebSocket>();
                vehicleClientList.add(this);

                 simSessionWebSocketMap.put(sim.trim(), vehicleClientList);
             }

        }

    }

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

    /**
     * 这个方法与上面几个方法不一样。没有用注解，是根据自己需要添加的方法。
     * @param message
     * @throws IOException
     */
    public   void sendMessage(String message,HttpServletRequest request) throws IOException{
        if(this.session.isOpen()){
            this.session.getBasicRemote().sendText(message);
            this.session.setMaxTextMessageBufferSize(102400);
//          this.session.getAsyncRemote().sendText(message);

        }

    }

    public   void sendMessage(String message) throws IOException{

        if(this.session.isOpen()){
            this.session.getBasicRemote().sendText(message);
            this.session.setMaxTextMessageBufferSize(102400);
//          this.session.getAsyncRemote().sendText(message);
        }
    }

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

    public static synchronized void addOnlineCount() {
        RealLocationWebSocket.onlineCount++;
    }

    public static synchronized void subOnlineCount() {
        RealLocationWebSocket.onlineCount--;
    }

    public static CopyOnWriteArraySet<RealLocationWebSocket> getWebSocketSet() {
        return webSocketSet;
    }

    public static void setWebSocketSet(CopyOnWriteArraySet<RealLocationWebSocket> webSocketSet) {
        RealLocationWebSocket.webSocketSet = webSocketSet;
    }


}

3、最后就是根据httpSessionId 实现 websocket session 共享了

首先就是实现 在RealWebSocket.java 中和 OnlineWebsocket 中都出现了的 GetHttpSessionConfigurator.class

import java.util.ArrayList;
import java.util.List;

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

public class GetHttpSessionConfigurator extends ServerEndpointConfig.Configurator
{

    @Override
    public <T> T getEndpointInstance(Class<T> clazz)
            throws InstantiationException {
        try {
            return clazz.newInstance();
        } catch (IllegalAccessException e) {
            InstantiationException ie = new InstantiationException();
            ie.initCause(e);
            throw ie;
        }
    }


    @Override
    public String getNegotiatedSubprotocol(List<String> supported,
            List<String> requested) {

        for (String request : requested) {
            if (supported.contains(request)) {
                return request;
            }
        }
        return "";
    }


    @Override
    public List<Extension> getNegotiatedExtensions(List<Extension> installed,
            List<Extension> requested) {

        List<Extension> result = new ArrayList<>();
        for (Extension request : requested) {
            if (installed.contains(request)) {
                result.add(request);
            }
        }
        return result;
    }


    @Override
    public boolean checkOrigin(String originHeaderValue) {
        return true;
    }

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

在上面这个过滤器里面，如果不出意外，你是会报一个空指针的，所以呢，在这里要修复一下

import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.annotation.WebListener;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

@WebListener
public class RequestListener implements ServletRequestListener {

    @Override
    public void requestDestroyed(ServletRequestEvent sre) {
        // TODO Auto-generated method stub

    }

    @Override
    public void requestInitialized(ServletRequestEvent sre) {
        HttpSession session = ((HttpServletRequest) sre.getServletRequest()).getSession();
    }

}

另外要将这个过滤器加到web.xml 中

    <listener>
        <listener-class>com.vshop.sys.listener.RequestListener</listener-class>
    </listener>

这样完了之后，应该就不会有什么问题了

就是通过 OnlineWebsocket.java 和 RealWebsocket .java中的httpSessionWebSocketMap 变量实现 两个 websocket Session 共享的