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

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
if('WebSocket' in window){
historyWebsocket = new WebSocket("ws://ip:端口/应用名/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
e826
)
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