使用ActiveMQ Artemis进行重连
Posted 郭大侠
tags:
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正常创建一个连接，在一段时间后心跳就会因为接收不到数据而强制停止。从而断开连接，那么无论是前端还是后端都应该有自己的实现重连机制。这里写一个关于前端实现重连的机制：
代码如下：
点击查看代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Chat Example Using STOMP Over WebSockets</title>
<link href="css/bootstrap.min.css" rel="stylesheet">
<link href="css/bootstrap.min.responsive.css" rel="stylesheet">
<style type="text/css">
body padding-top: 40px;
</style>
</head>
<body>
<div class="navbar navbar-fixed-top">
<div class="navbar-inner">
<div class="container">
<a class="brand" href="#">Stomp Over WebSocket Chat Example</a>
</div>
</div>
</div>
<div class="container-fluid">
<div class="row-fluid">
<div class="span6">
<div id="connect">
<div class="page-header">
<h2>Server Login</h2>
</div>
<form class="form-horizontal" id=\'connect_form\'>
<fieldset>
<div class="control-group" >
<label>WebSocket URL</label>
<div class="controls">
<input name=url id=\'connect_url\' value=\'ws://127.0.0.1:61613\' type="text">
</div>
</div>
<div class="control-group" >
<label>User</label>
<div class="controls">
<input id=\'connect_login\' placeholder="User Login" value="admin" type="text">
</div>
</div>
<div class="control-group">
<label>ID</label>
<div class="controls">
<input id=\'connect_id\' placeholder="ID" value="" type="text">
</div>
</div>
<div class="control-group">
<label>Password</label>
<div class="controls">
<input id=\'connect_passcode\' placeholder="User Password" value="password" type="password">
</div>
</div>
<div class="control-group">
<label>Destination</label>
<div class="controls">
<input id=\'destination\' placeholder="Destination" value="world" type="text">
</div>
</div>
<div class="form-actions">
<button id=\'connect_submit\' type="submit" class="btn btn-large btn-primary">Connect</button>
</div>
</fieldset>
</form>
</div>
<div id="connected" >
<div class="page-header">
<h2>Chat Room</h2>
</div>
<div id="messages">
</div>
<form class="well form-search" id=\'send_form\'>
<button class="btn" type="button" id=\'disconnect\' >Disconnect</button>
<input class="input-medium" id=\'send_form_input\' placeholder="Type your message here" class="span6"/>
<button class="btn" type="submit">Send</button>
</form>
</div>
</div>
<div class="span4">
<div class="page-header">
<h2>Debug Log</h2>
</div>
<pre id="debug"></pre>
</div>
</div>
</div>
<!-- Scripts placed at the end of the document so the pages load faster -->
<script src=\'js/jquery-1.7.2.min.js\'></script>
<script src="js/stomp2.3.3.js"></script>
<script>//<![CDATA[
//定义全局变量，表明一个session
var client = null;
const data = new Map();
function connect() //定义链接函数
if(client == null || !client.connected)
//var url = \'http://localhost:8164/websocket\';
//var url = \'/websocket\';
var headers=
\'login\':data.get(\'login\'),
\'passcode\':data.get(\'passcode\'),
\'client-id\': data.get(\'id\')
;
client = Stomp.client(data.get(\'url\'));
client.connect(headers, connectCallback ,errorCallback );
else
$("#debug").append("当前处于链接状态" + "\\n");
function connectCallback (frame) //链接成功时的回调函数
client.subscribe(\'world\', function (result)
var content = result.body;
$("#messages").append(\'<p>\'+content+\'</p>\' + "\\n");
, );
function errorCallback()//链接失败时的回调函数，此函数从新调用链接方法，造成循环，直到链接成功
connect();
var d = new Date();
console.log(d.getDate()+d.getHours()+d.getMinutes()+"执行了重连。。。");
$(document).ready(function()
if(window.WebSocket)
$(\'#connect_form\').submit(function()
data.set(\'url\',$("#connect_url").val());
data.set(\'login\',$("#connect_login").val());
data.set(\'passcode\',$("#connect_passcode").val());
data.set(\'id\',$("#connect_id").val());
connect();//创建链接
$(\'#connect\').remove();
$(\'#connected\').css(\'display\',\'\');
// this allows to display debug logs directly on the web page
//client.debug = function(str)
//$("#messages").append("<p>" +str.body+ "</p>" +"\\n");
//$("#debug").append(str + "\\n");
// ;
return false;
);
$(\'#disconnect\').click(function()
client.disconnect(function()
$(\'#connected\').fadeOut( duration: \'fast\' );
$(\'#connect\').fadeIn();
$("#messages").html("")
);
location.reload ();
return false;
);
$(\'#send_form\').submit(function()
var text = $(\'#send_form_input\').val();
if (text)
client.send(\'world\', , text);
$(\'#send_form_input\').val("");
return false;
);
else
$("#connect").html("\\
<h1>Get a new Web Browser!</h1>\\
<p>\\
Your browser does not support WebSockets. This example will not work properly.<br>\\
Please use a Web Browser with WebSockets support (WebKit or Google Chrome).\\
</p>\\
");
);
//]]></script>
</body>
</html>
实现原理很简单，使用stomp进行连接，里面定义了连接方法client.connect(headers, connectCallback ,errorCallback );分别是头信息，连接成功回调，和连接失败回调，
底层实现的是windows.setinterval()方法进行定时检测连接是否正常。这样服务启动后就会一直有正常的连接支持。遗憾的是这种连接方法并不能使同一个sessionid的连接重连。而是取到我们填写的信息再次连接。
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