一、介绍
1.两种方式，一种使用tomcat的 websocket 实现，一种使用spring的websocket
2.tomcat的方式需要tomcat 7.x，jee7的支持。
3.spring与websocket整合需要spring 4.x，并且使用了socketjs，对不支持websocket的浏览器可以模拟websocket使用
二、方式一：tomcat
使用这种方式无需别的任何配置，只需服务端一个处理类，
服务器端代码
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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( "已连接" ); } @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( "给一个人" , jsonto.get( "to" ).tostring()); } else { sendmessageall( "给所有人" ); } } @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; } } |
客户端js
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var websocket = null ; var username = localstorage.getitem( "name" ); //判断当前浏览器是否支持websocket if ( 'websocket' in window) { websocket = new websocket( "ws://" + document.location.host + "/webchat/websocket/" + username + "/" + _img); } 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) { setmessageinnerhtml(event.data); } //连接关闭的回调方法 websocket.onclose = function() { setmessageinnerhtml( "websocket连接关闭" ); } //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(); } //关闭websocket连接 function closewebsocket() { websocket.close(); } |
发送消息只需要使用websocket.send([发送消息])，就可以触发服务端的onmessage()方法，当连接时，触发服务器端onopen()方法，此时也可以调用发送消息的方法去发送消息。关闭websocket时，触发服务器端onclose()方法，此时也可以发送消息，但是不能发送给自己，因为自己的已经关闭了连接，但是可以发送给其他人。
三、方法二：spring整合
websocketconfig.java
这个类是配置类，所以需要在spring mvc配置文件中加入对这个类的扫描，第一个addhandler是对正常连接的配置，第二个是如果浏览器不支持websocket，使用socketjs模拟websocket的连接。
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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 @enablewebsocket public 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
这个类的作用就是在连接成功前和成功后增加一些额外的功能，constants.java类是一个工具类，两个常量。
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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区分websockethandler，以便定向发送消息 string username = * (string) session.getattribute(constants.session_username); if * (username==null) { username="default-system"; } * attributes.put(constants.websocket_username,username); * * } } */ //使用username区分websockethandler，以便定向发送消息(使用shiro获取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
这个类是对消息的一些处理，比如是发给一个人，还是发给所有人，并且前端连接时触发的一些动作
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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; // 这个会出现性能问题，最好用map来存储，key用userid private static logger logger = logger.getlogger(chatmessagehandler. class ); static { users = new arraylist<websocketsession>(); } /** * 连接成功时候，会触发ui上onopen方法 */ @override public void afterconnectionestablished(websocketsession session) throws exception { system.out.println( "connect to the websocket success......" ); users.add(session); // 这块会实现自己业务，比如，当用户登录后，会把离线消息推送给用户 // textmessage returnmessage = new textmessage("你将收到的离线"); // session.sendmessage(returnmessage); } /** * 在ui在用js调用websocket.send()时候，会调用该方法 */ @override protected void handletextmessage(websocketsession session, textmessage message) throws exception { sendmessagetousers(message); //super.handletextmessage(session, message); } /** * 给某个用户发送消息 * * @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 ; } } } /** * 给所有在线用户发送消息 * * @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，同时需要增加对websocketconfig.java类的扫描，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> |
客户端
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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(); //调用后台handletextmessage方法 websocket.send(msg); } else { alert( "连接失败!" ); } }); </script> |
注意导入socketjs时要使用地址全称，并且连接使用的是http而不是websocket的ws
总结
以上所述是小编给大家介绍的java 实现websocket的两种方式实例详解，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对网站的支持！
原文链接：https://blog.csdn.net/sinat_23324343/article/details/81237973
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