1、先建立一个Maven项目，如果是老项目，也可转成maven项目，参见我之前写的一篇帮助：
Myeclipse普通java项目转maven项目
2、pom.xml引用相关jar包，1.7之后支持，配置如下：
<dependencies>
<!-- <dependency>
<groupId>javax.websocket</groupId>
<artifactId>javax.websocket-api</artifactId>
<version>1.1</version>
<scope>provided</scope>
</dependency> -->
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-api</artifactId>
<version>7.0</version>
<scope>provided</scope>
</dependency>
</dependencies>
tomcat7和jave EE 1.7都支持，注意引用一个，不要重复。
3、编写事件拦截处理代码：
ZhiWebSocketHandler.java
package com.yyxz.main;
import java.util.regex.Pattern;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.jfinal.handler.Handler;
import com.jfinal.kit.StrKit;
public class ZhiWebSocketHandler extends Handler {
private Pattern filterUrlRegxPattern;
public ZhiWebSocketHandler(String filterUrlRegx) {
if (StrKit.isBlank(filterUrlRegx))
throw new IllegalArgumentException("The para filterUrlRegx can not be blank.");
filterUrlRegxPattern = Pattern.compile(filterUrlRegx);
}
@Override
public void handle(String target, HttpServletRequest request, HttpServletResponse response, boolean[] isHandled) {
// TODO Auto-generated method stub
if (filterUrlRegxPattern.matcher(target).find())
return ;
else {
next.handle(target, request, response, isHandled);
}
}
}
在JFinal Config中进行注册：
public class DemoConfig extends JFinalConfig {
//...
public void configHandler(Handlers me) {
me.add(new ContextPathHandler("ctx"));
me.add(new ZhiWebSocketHandler("^/websocket"));
// 也可以使用UrlSkipHandler，就不用编写Handler处理类了
// me.add(new UrlSkipHandler("^/websocket", false));
}
//...
}
4、后台监听websocket代码：
WebSocketController.java
package com.yyxz.controller;
import java.io.IOException;
import javax.websocket.OnClose;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;
@ServerEndpoint("/websocket")
public class WebSocketController {
public WebSocketController() {
System.out.println(" WebSocket init~~~");
}
@OnOpen
public void onOpen(Session session) {
System.out.println("onOpen");
}
@OnClose
public void onClose(Session session) {
System.out.println("onClose");
}
// @OnError
// public void onError(Session session) {
// System.out.println("onError");
// }
@OnMessage
public void onMessage(String requestJson, Session session)
throws IOException {
requestJson = "一一小知回复：" + requestJson;
System.out.println(requestJson);
session.getBasicRemote().sendText(requestJson);
}
}
5、在前端发起，编写页面：
webSocketTest.jsp
<%@page contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<!-- for HTML5 -->
<title>Java后端WebSocket的Tomcat实现</title>
</head>
<body>
Welcome
<br />
<input id="text" type="text" />
<button onclick="send()">发送消息</button>
<hr />
<button onclick="closeWebSocket()">关闭WebSocket连接</button>
<hr />
<div id="message"></div>
</body>
<script type="text/javascript">
var websocket = null;
//判断当前浏览器是否支持WebSocket
if ('WebSocket' in window) {
websocket = new WebSocket("ws://localhost:8080/yiyixiaozhi/websocket");
}
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();
}
//将消息显示在网页上
function setMessageInnerHTML(innerHTML) {
document.getElementById('message').innerHTML += innerHTML + '<br/>';
}
//关闭WebSocket连接
function closeWebSocket() {
websocket.close();
}
//发送消息
function send() {
var message = document.getElementById('text').value;
websocket.send(message);
}
</script>
</html>
结果如下：
image.png
image.png
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