使用webSocket实现及时通信

骑猪看日落 2022-05-29 23:44 425阅读 0赞

本方案是为了解决前后台及时通信设计的,例如后台代码触发一个事件,可以及时的传递给前台,也就是消息的推送功能.  
关于消息的推送,方案1是使用定时任务,Cron表达式设置每分钟处理一下后台逻辑进行事件的判断.方案2是使用webSocket建立消息通信通道,挂起一个线程进行时间的判断和消息推送.虽然都能实现消息推送的功能,但是方案二明显效率更高,对服务器造成的压力相对于方案1来说也更小,这里就简单介绍下使用第二种方案进行消息的及时推送实现方法.  
首先说下使用webSocket进行访问是路径格式:ws:// path + “wsMy?jspCode=” + jspCode  
以WS开头,后面可以追加参数,上文路径是中的wsMy是为了接下来的过滤器过滤,防止恶意访问.  
首先添加webSocket依赖:

<dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring-websocket</artifactId>
 <version>4.0.1.RELEASE</version>
 </dependency>

接下来就是前台页面上的触发访问webSocket:

因为本案例中访问的是当前服务器的路径,所以要对当前服务器的IP以及端口号进行获取,然后赋值给webSocket的访问路径:

/*获取当前用户id*/
    var addrAndPort = "";
    function getAddrAndport() { 
        $.ajax({
            type : "get",
            url : "${ctx}/getAddrAndport",
            beforeSend: function () { 
                //加载中
                waitload();
            },
            success : function(data) { 
                addrAndPort = data;
            }
        })
    }
    
    后台获取IP以及端口号返回到前台:
    @RequestMapping(value = "/getAddrAndport", method = { RequestMethod.GET,
                RequestMethod.POST })
        @ResponseBody
        public Object getAddrAndport(HttpServletRequest request,
                                    HttpServletResponse response) {
            String addrAndPort = "";
            addrAndPort = request.getLocalAddr()+":"+request.getLocalPort();
            return addrAndPort;
        }
    之前查找资料,获取当前系统的IP以及端口号的方法,杂乱,还是直接从HttpServletRequest 中直接获取最为直接和准确.

当前台页面触发访问的时候,后台服务器接收到访问请求并且进行处理,这时候我把后台关于webSocket的请求分为三个文件:  
1:HandShake.java

package com.yyx.webSocket;
 
 import org.springframework.http.server.ServerHttpRequest;
 import org.springframework.http.server.ServerHttpResponse;
 import org.springframework.http.server.ServletServerHttpRequest;
 import org.springframework.web.socket.WebSocketHandler;
 import org.springframework.web.socket.server.HandshakeInterceptor;
 
 import java.util.*;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Map.Entry;
 /** * Created by zhangrui on 2018/1/22. */
 public class HandShake implements HandshakeInterceptor{ 
 @Override
 public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Map<String, Object> attributes) throws Exception {
 // TODO Auto-generated method stub
 String jspCode = ((ServletServerHttpRequest) request).getServletRequest().getParameter("jspCode");
 // 标记用户
 // String userId = (String) ((ServletServerHttpRequest) request).getServletRequest().getSession().getAttribute("userId");
 if(jspCode!=null){
 attributes.put("jspCode", jspCode);
 }else{
 return false;
 }
 return true;
 }
 
 @Override
 public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Exception exception) {
 // TODO Auto-generated method stub
 }
 }

2.MyWebSocketConfig.java

package com.yyx.webSocket;
    
    import org.springframework.stereotype.Component;
    import org.springframework.web.servlet.config.annotation.EnableWebMvc;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
    import org.springframework.web.socket.config.annotation.EnableWebSocket;
    import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
    import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;
    
    import javax.annotation.Resource;
    
    /** * Created by zhangrui on 2018/1/22. */
    @Component
    @EnableWebMvc
    @EnableWebSocket
    public class MyWebSocketConfig extends WebMvcConfigurerAdapter implements WebSocketConfigurer { 
        @Resource
        MyWebSocketHandler handler;
        @Override
        public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
            // TODO Auto-generated method stub
            registry.addHandler(handler, "/wsMy");
            registry.addHandler(handler, "/wsMy/sockjs").withSockJS();
        }
    }

3:MyWebSockethandler.java访问成功后的处理逻辑,本文中是使用线程写的,因人而异.

package com.yyx.webSocket;
 
 import com.google.gson.GsonBuilder;
 import com.yyx.zbhr.controller.MemoController;
 import com.yyx.zbhr.entity.MemoEntity;
 import com.yyx.zbhr.entity.NotepadEntity;
 import com.yyx.zbhr.entity.User;
 import com.yyx.zbhr.service.MMemoService;
 import com.yyx.zbhr.service.MPersonInfoService;
 import com.yyx.zbhr.utils.UserUtil;
 import org.apache.commons.collections.map.HashedMap;
 import org.apache.shiro.authz.annotation.RequiresAuthentication;
 import org.apache.shiro.authz.annotation.RequiresPermissions;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Component;
 import org.springframework.web.socket.*;
 
 import javax.servlet.http.HttpSession;
 import java.io.IOException;
 import java.net.URI;
 import java.text.SimpleDateFormat;
 import java.util.*;
 import java.util.Map.*;
 
 /** * Created by zhangrui on 2018/1/22. */
 @Component
 public class MyWebSocketHandler implements WebSocketHandler {
 public static final Map<String, WebSocketSession> userSocketSessionMap;
 private static Logger logger = LoggerFactory.getLogger(MyWebSocketHandler.class);
 private static Calendar fromCal=Calendar.getInstance();
 @Autowired(required = false)
 private MPersonInfoService mPersonInfoService;
 
 @Autowired(required = false)
 private MMemoService mMemoService;
 static {
 userSocketSessionMap = new HashMap<String, WebSocketSession>();
 }
 public static WebSocketSession session1 ;
 @Override
 public void afterConnectionEstablished(WebSocketSession session) throws Exception {
 // TODO Auto-generated method stub
 //HttpSession httpSession = (HttpSession) session;
 SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd hh:mm");
 //调用接口获取ID
 //Long userId = mMemoService.getCurrentUserId();
 Map<String,Object> map = new HashedMap();
 /*//wsMy?jspCode=23*/
 String uri = session.getUri().toString();
 String[] split = uri.split("=");
 int currentUserId = Integer.parseInt(split[1]);
 // TODO 自动shiro获取id失败
 map.put("userId",currentUserId);
 String jspCode = (String) session.getHandshakeAttributes().get("jspCode");
 if (userSocketSessionMap.get(jspCode) == null) {
 userSocketSessionMap.put(jspCode, session);
 }
 new Thread(new Runnable() {
 public void run() {
 while(true){
 Date date = new Date();
 String format = simpleDateFormat.format(date);
 List<NotepadEntity> notepadEntities = mMemoService.selectNotepadForNotice(map);
 for (int i = 0; i < notepadEntities.size(); i++) { 
 String format1 = simpleDateFormat.format(notepadEntities.get(i).getStarTime());
 String format2 = simpleDateFormat.format(notepadEntities.get(i).getEndTime());
 StringBuffer message = new StringBuffer();
 int flag1 = date.compareTo(notepadEntities.get(i).getEndTime());
 int flag2 = date.compareTo(notepadEntities.get(i).getStarTime());
 if (flag1 < 0 && flag2 >= 0) {
 try {
 String noteType = "";
 if (notepadEntities.get(i).getNoteType() == 1){
 noteType = "工作";
 }else if (notepadEntities.get(i).getNoteType() == 2){
 noteType = "生活";
 }else if (notepadEntities.get(i).getNoteType() == 3){
 noteType = "家庭";
 }else if (notepadEntities.get(i).getNoteType() == 4){
 noteType = "私密";
 }else {
 noteType = "其他";
 }
 message.append(notepadEntities.get(i).getId()+"*");
 message.append("日程类型:"+noteType+"");
 message.append("起始时间:"+format1+"");
 message.append("终止时间:"+format2+"");
 message.append("主题:"+notepadEntities.get(i).getTitle()+"");
 message.append("内容:"+notepadEntities.get(i).getContent()+"");
 session.sendMessage(new TextMessage(message,true));
 //session.sendMessage(new TextMessage(new GsonBuilder().create().toJson("\"日程类型\":\"" + noteType + "\";\"日程时间\":\"" + simpleDateFormat.format(notepadEntities.get(i).getStarTime())+"--"+simpleDateFormat.format(notepadEntities.get(i).getEndTime()) + "\";\"标题:\":\"" + notepadEntities.get(i).getTitle() + "\";\"内容:\":\"" + notepadEntities.get(i).getContent() + "\"")));
 //session.sendMessage(new TextMessage("日程提醒\n日程事件:"+format1+"--"+format2+"\n"+"标题:"+notepadEntities.get(i).getTitle()+"\n"+"内容:"+notepadEntities.get(i).getContent()+"类型:"+noteType+"\n"+""));
 } catch (IOException e) {
 e.printStackTrace();
 }
 }else if(flag1>0){
 try {
 String noteType = "";
 if (notepadEntities.get(i).getNoteType() == 1){
 noteType = "工作";
 }else if (notepadEntities.get(i).getNoteType() == 2){
 noteType = "生活";
 }else if (notepadEntities.get(i).getNoteType() == 3){
 noteType = "家庭";
 }else if (notepadEntities.get(i).getNoteType() == 4){
 noteType = "私密";
 }else {
 noteType = "其他";
 }
 message.append(notepadEntities.get(i).getId()+"*");
 message.append("<h3 style=\"color:red\">日程过期提醒</h3>");
 message.append("日程类型:"+noteType+"");
 message.append("起始时间:"+format1+"");
 message.append("终止时间:"+format2+"");
 message.append("主题:"+notepadEntities.get(i).getTitle()+"");
 message.append("内容:"+notepadEntities.get(i).getContent()+"");
 session.sendMessage(new TextMessage(message,true));
 //session.sendMessage(new TextMessage(new GsonBuilder().create().toJson("\"日程类型\":\"" + noteType + "\";\"日程时间\":\"" + simpleDateFormat.format(notepadEntities.get(i).getStarTime())+"--"+simpleDateFormat.format(notepadEntities.get(i).getEndTime()) + "\";\"标题:\":\"" + notepadEntities.get(i).getTitle() + "\";\"内容:\":\"" + notepadEntities.get(i).getContent() + "\"")));
 //session.sendMessage(new TextMessage("日程提醒\n日程事件:"+format1+"--"+format2+"\n"+"标题:"+notepadEntities.get(i).getTitle()+"\n"+"内容:"+notepadEntities.get(i).getContent()+"类型:"+noteType+"\n"+""));
 } catch (IOException e) {
 e.printStackTrace();
 }
 }else {
 String noteType = "";
 if (notepadEntities.get(i).getNoteType() == 1){
 noteType = "工作";
 }else if (notepadEntities.get(i).getNoteType() == 2){
 noteType = "生活";
 }else if (notepadEntities.get(i).getNoteType() == 3){
 noteType = "家庭";
 }else if (notepadEntities.get(i).getNoteType() == 4){
 noteType = "私密";
 }else {
 noteType = "其他";
 }
 //session.sendMessage(new TextMessage(new GsonBuilder().create().toJson("\"日程类型 \":\" " + noteType + "\";\"日程时间\":\"" + simpleDateFormat.format(notepadEntities.get(i).getStarTime())+"--"+simpleDateFormat.format(notepadEntities.get(i).getEndTime()) + "\";\"标题\":\"" + notepadEntities.get(i).getTitle() + "\";\"内容 \":\"" + notepadEntities.get(i).getContent() + "\"")));
 //session.sendMessage(new TextMessage(new GsonBuilder().create().toJson("\"number\":\"" + i + "\";\"deptId\":\"" + format + "\";\"事件:\":\"" + "这只是哥哥拿来测试的事件" + i + "\"")));
 /* message.append("日程类型:"+noteType+""); message.append("起始时间:"+format1+""); message.append("终止时间:"+format2+""); message.append("主题:"+notepadEntities.get(i).getTitle()+""); message.append("内容:"+notepadEntities.get(i).getContent()+""); session.sendMessage(new TextMessage(message,true));*/
 try {
 session.sendMessage(new TextMessage("木有消息啊",true));
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
 }
 try {
 Thread.sleep(1000*60);
 } catch (InterruptedException e) {
 e.printStackTrace();
 }
 }
 
 }
 }).start();
 }
 
 @Override
 public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {
 // TODO Auto-generated method stub
 //Message msg=new Gson().fromJson(message.getPayload().toString(),Message.class);
 //msg.setDate(new Date());
 // sendMessageToUser(msg.getTo(), new TextMessage(new GsonBuilder().setDateFormat("yyyy-MM-dd HH:mm:ss").create().toJson(msg)));
 
 session.sendMessage(message);
 }
 
 @Override
 public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
 // TODO Auto-generated method stub
 if (session.isOpen()) {
 session.close();
 }
 Iterator<Map.Entry<String, WebSocketSession>> it = userSocketSessionMap
 .entrySet().iterator();
 // 移除Socket会话
 while (it.hasNext()) {
 Map.Entry<String, WebSocketSession> entry = it.next();
 if (entry.getValue().getId().equals(session.getId())) {
 userSocketSessionMap.remove(entry.getKey());
 System.out.println("Socket会话已经移除:用户ID" + entry.getKey());
 break;
 }
 }
 }
 
 @Override
 public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
 // TODO Auto-generated method stub
 System.out.println("Websocket:" + session.getId() + "已经关闭");
 Iterator<Entry<String, WebSocketSession>> it = userSocketSessionMap
 .entrySet().iterator();
 // 移除Socket会话
 while (it.hasNext()) {
 Entry<String, WebSocketSession> entry = it.next();
 if (entry.getValue().getId().equals(session.getId())) {
 userSocketSessionMap.remove(entry.getKey());
 //TODO 对webSocket资源进行回收
 System.gc();
 System.out.println("Socket会话已经移除:用户ID" + entry.getKey());
 break;
 }
 }
 }
 
 @Override
 public boolean supportsPartialMessages() {
 return false;
 }
 public void broadcast(final TextMessage message) throws IOException {
 Iterator<Entry<String, WebSocketSession>> it = userSocketSessionMap
 .entrySet().iterator();
 
 // 多线程群发
 while (it.hasNext()) {
 
 final Entry<String, WebSocketSession> entry = it.next();
 
 if (entry.getValue().isOpen()) {
 new Thread(new Runnable() {
 
 public void run() {
 try {
 if (entry.getValue().isOpen()) {
 entry.getValue().sendMessage(message);
 }
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
 
 }).start();
 }
 
 }
 }
 public void sendMessageToJsp(final TextMessage message,String type) throws IOException {
 Iterator<Entry<String, WebSocketSession>> it = userSocketSessionMap
 .entrySet().iterator();
 
 // 多线程群发
 while (it.hasNext()) {
 
 final Entry<String, WebSocketSession> entry = it.next();
 if (entry.getValue().isOpen() && entry.getKey().contains(type)) {
 new Thread(new Runnable() {
 
 public void run() {
 try {
 if (entry.getValue().isOpen()) {
 entry.getValue().sendMessage(message);
 }
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
 
 }).start();
 }
 
 }
 }
 
 }

第三个文件是核心,具体的代码是实验代码,有一部分是冗余代码,粘贴出来仅供参考,值得一提的是,在webSocket进行sendMessage的时候,可选的message格式有多种,当时博主想传回类json,但是传到前台发现处理比较麻烦,所以就传回了StringBuffer类型的,至于StringBuffer和StringBuidder之间的选择,看情况决定,这里不多言.再展示下消息传递后的效果图:  
![这里写图片描述][70]

对返回到前台的消息处理使用的layer进行弹出,比较好用,样式多.可以直接从layer官网查询样式进行使用,网址….百度.  
最后一点,本文中使用的web容器及版本是Tomcat8.0.48,虽然有人说在Tomcat8.0之前,不支持webSocket消息通讯,说的是那时候webSocket协议未制定,但是….博主试了下使用Tomcat7.9可行,所以这里就不再多说废话啦,博主也只是个门外汉,更多更细的webSocket知识点还是留待大家自行发掘吧!  
最后一点,请不要诟病博主的访问路径:getAddrAndport,虽然不规范,但是….这破习惯一下子难改啊…逐步改正.  
完.

[70]: /images/20220530/de68217d15d240c782e14aec4cf20cba.png