一、介紹
1.兩種方式，一種使用tomcat的websocket實現，一種使用spring的websocket
2.tomcat的方式需要tomcat 7.x，jee7的支持。
3.spring與websocket整合需要spring 4.x，并且使用了socketjs，對不支持websocket的瀏覽器可以模擬websocket使用
二、方式一：tomcat
使用這種方式無需別的任何配置，只需服務端一個處理類，
服務器端代碼
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package com.socket; import java.io.ioexception; import java.util.map; import java.util.concurrent.concurrenthashmap; import javax.websocket.*; import javax.websocket.server.pathparam; import javax.websocket.server.serverendpoint; import net.sf.json.jsonobject; @serverendpoint("/websocket/{username}") public class websocket { private static int onlinecount = 0; private static map<string, websocket> clients = new concurrenthashmap<string, websocket>(); private session session; private string username; @onopen public void onopen(@pathparam("username") string username, session session) throws ioexception { this.username = username; this.session = session; addonlinecount(); clients.put(username, this); system.out.println("已連接"); } @onclose public void onclose() throws ioexception { clients.remove(username); subonlinecount(); } @onmessage public void onmessage(string message) throws ioexception { jsonobject jsonto = jsonobject.fromobject(message); if (!jsonto.get("to").equals("all")){ sendmessageto("給一個人", jsonto.get("to").tostring()); }else{ sendmessageall("給所有人"); } } @onerror public void onerror(session session, throwable error) { error.printstacktrace(); } public void sendmessageto(string message, string to) throws ioexception { // session.getbasicremote().sendtext(message); //session.getasyncremote().sendtext(message); for (websocket item : clients.values()) { if (item.username.equals(to) ) item.session.getasyncremote().sendtext(message); } } public void sendmessageall(string message) throws ioexception { for (websocket item : clients.values()) { item.session.getasyncremote().sendtext(message); } } public static synchronized int getonlinecount() { return onlinecount; } public static synchronized void addonlinecount() { websocket.onlinecount++; } public static synchronized void subonlinecount() { websocket.onlinecount--; } public static synchronized map<string, websocket> getclients() { return clients; } } |
客戶端js
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var websocket = null; var username = localstorage.getitem("name"); //判斷當前瀏覽器是否支持websocket if ('websocket' in window) { websocket = new websocket("ws://" + document.location.host + "/webchat/websocket/" + username + "/"+ _img); } else { alert('當前瀏覽器 not support websocket') } //連接發生錯誤的回調方法 websocket.onerror = function() { setmessageinnerhtml("websocket連接發生錯誤"); }; //連接成功建立的回調方法 websocket.onopen = function() { setmessageinnerhtml("websocket連接成功"); } //接收到消息的回調方法 websocket.onmessage = function(event) { setmessageinnerhtml(event.data); } //連接關閉的回調方法 websocket.onclose = function() { setmessageinnerhtml("websocket連接關閉"); } //監聽窗口關閉事件，當窗口關閉時，主動去關閉websocket連接，防止連接還沒斷開就關閉窗口，server端會拋異常。 window.onbeforeunload = function() { closewebsocket(); } //關閉websocket連接 function closewebsocket() { websocket.close(); } |
發送消息只需要使用websocket.send(“發送消息”)，就可以觸發服務端的onmessage()方法，當連接時，觸發服務器端onopen()方法，此時也可以調用發送消息的方法去發送消息。關閉websocket時，觸發服務器端onclose()方法，此時也可以發送消息，但是不能發送給自己，因為自己的已經關閉了連接，但是可以發送給其他人。
三、方法二：spring整合
websocketconfig.java
這個類是配置類，所以需要在spring mvc配置文件中加入對這個類的掃描，第一個addhandler是對正常連接的配置，第二個是如果瀏覽器不支持websocket，使用socketjs模擬websocket的連接。
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package com.websocket; import org.springframework.context.annotation.bean; import org.springframework.context.annotation.configuration; 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 org.springframework.web.socket.handler.textwebsockethandler; @configuration@enablewebsocketpublic class websocketconfig implements websocketconfigurer { @override public void registerwebsockethandlers(websockethandlerregistry registry) { registry.addhandler(chatmessagehandler(),"/websocketserver").addinterceptors(new chathandshakeinterceptor()); registry.addhandler(chatmessagehandler(), "/sockjs/websocketserver").addinterceptors(new chathandshakeinterceptor()).withsockjs(); } @bean public textwebsockethandler chatmessagehandler(){ return new chatmessagehandler(); } } |
chathandshakeinterceptor.java
這個類的作用就是在連接成功前和成功后增加一些額外的功能，constants.java類是一個工具類，兩個常量。
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package com.websocket; import java.util.map; import org.apache.shiro.securityutils; import org.springframework.http.server.serverhttprequest; import org.springframework.http.server.serverhttpresponse; import org.springframework.web.socket.websockethandler; import org.springframework.web.socket.server.support.httpsessionhandshakeinterceptor; public class chathandshakeinterceptor extends httpsessionhandshakeinterceptor { @override public boolean beforehandshake(serverhttprequest request, serverhttpresponse response, websockethandler wshandler, map<string, object> attributes) throws exception { system.out.println("before handshake"); /* * if (request instanceof servletserverhttprequest) { * servletserverhttprequest servletrequest = (servletserverhttprequest) * request; httpsession session = * servletrequest.getservletrequest().getsession(false); if (session != * null) { //使用username區分websockethandler，以便定向發送消息 string username = * (string) session.getattribute(constants.session_username); if * (username==null) { username="default-system"; } * attributes.put(constants.websocket_username,username); * * } } */ //使用username區分websockethandler，以便定向發送消息(使用shiro獲取session,或是使用上面的方式) string username = (string) securityutils.getsubject().getsession().getattribute(constants.session_username); if (username == null) { username = "default-system"; } attributes.put(constants.websocket_username, username); return super.beforehandshake(request, response, wshandler, attributes); } @override public void afterhandshake(serverhttprequest request, serverhttpresponse response, websockethandler wshandler, exception ex) { system.out.println("after handshake"); super.afterhandshake(request, response, wshandler, ex); } } |
chatmessagehandler.java
這個類是對消息的一些處理，比如是發給一個人，還是發給所有人，并且前端連接時觸發的一些動作
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package com.websocket; import java.io.ioexception; import java.util.arraylist; import org.apache.log4j.logger; import org.springframework.web.socket.closestatus; import org.springframework.web.socket.textmessage; import org.springframework.web.socket.websocketsession; import org.springframework.web.socket.handler.textwebsockethandler; public class chatmessagehandler extends textwebsockethandler { private static final arraylist<websocketsession> users;// 這個會出現性能問題，最好用map來存儲，key用userid private static logger logger = logger.getlogger(chatmessagehandler.class); static { users = new arraylist<websocketsession>(); } /** * 連接成功時候，會觸發ui上onopen方法 */ @override public void afterconnectionestablished(websocketsession session) throws exception { system.out.println("connect to the websocket success......"); users.add(session); // 這塊會實現自己業務，比如，當用戶登錄后，會把離線消息推送給用戶 // textmessage returnmessage = new textmessage("你將收到的離線"); // session.sendmessage(returnmessage); } /** * 在ui在用js調用websocket.send()時候，會調用該方法 */ @override protected void handletextmessage(websocketsession session, textmessage message) throws exception { sendmessagetousers(message); //super.handletextmessage(session, message); } /** * 給某個用戶發送消息 * * @param username * @param message */ public void sendmessagetouser(string username, textmessage message) { for (websocketsession user : users) { if (user.getattributes().get(constants.websocket_username).equals(username)) { try { if (user.isopen()) { user.sendmessage(message); } } catch (ioexception e) { e.printstacktrace(); } break; } } } /** * 給所有在線用戶發送消息 * * @param message */ public void sendmessagetousers(textmessage message) { for (websocketsession user : users) { try { if (user.isopen()) { user.sendmessage(message); } } catch (ioexception e) { e.printstacktrace(); } } } @override public void handletransporterror(websocketsession session, throwable exception) throws exception { if (session.isopen()) { session.close(); } logger.debug("websocket connection closed......"); users.remove(session); } @override public void afterconnectionclosed(websocketsession session, closestatus closestatus) throws exception { logger.debug("websocket connection closed......"); users.remove(session); } @override public boolean supportspartialmessages() { return false; } } |
spring-mvc.xml
正常的配置文件，同時需要增加對websocketconfig.java類的掃描，并且增加
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xmlns:websocket="http://www.springframework.org/schema/websocket" http://www.springframework.org/schema/websocket <a target="_blank" href="http://www.springframework.org/schema/websocket/spring-websocket-4.1.xsd" rel="external nofollow" >http://www.springframework.org/schema/websocket/spring-websocket-4.1.xsd</a> |
客戶端
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<script type="text/javascript" src="http://localhost:8080/bank/js/sockjs-0.3.min.js"></script> <script> var websocket; if ('websocket' in window) { websocket = new websocket("ws://" + document.location.host + "/bank/websocketserver"); } else if ('mozwebsocket' in window) { websocket = new mozwebsocket("ws://" + document.location.host + "/bank/websocketserver"); } else { websocket = new sockjs("http://" + document.location.host + "/bank/sockjs/websocketserver"); } websocket.onopen = function(evnt) {}; websocket.onmessage = function(evnt) { $("#test").html("(<font color='red'>" + evnt.data + "</font>)") }; websocket.onerror = function(evnt) {}; websocket.onclose = function(evnt) {} $('#btn').on('click', function() { if (websocket.readystate == websocket.open) { var msg = $('#id').val(); //調用后臺handletextmessage方法 websocket.send(msg); } else { alert("連接失敗!"); } }); </script> |
注意導入socketjs時要使用地址全稱，并且連接使用的是http而不是websocket的ws
總結
以上所述是小編給大家介紹的java 實現websocket的兩種方式實例詳解，希望對大家有所幫助，如果大家有任何疑問請給我留言，小編會及時回復大家的。在此也非常感謝大家對服務器之家網站的支持！
原文鏈接：https://blog.csdn.net/sinat_23324343/article/details/81237973
