正在浏览:多ajax请求的各类解决方案(同步, 队列, cancel请求)
            "codetitle">复制代码 代码如下: 
(function ($) { 
var ajaxRequest = {}; 
$.ajaxQueue = function (settings) { 
var options = $.extend({ className: 'DEFEARTNAME' }, $.ajaxSettings, settings); 
var _complete = options.complete; 
$.extend(options, { 
complete: function () { 
if (_complete) 
_complete.apply(this, arguments); 
if ($(document).queue(options.className).length > 0) { 
$(document).dequeue(options.className); 
} else { 
ajaxRequest[options.className] = false; 
} 
} 
}); 
$(document).queue(options.className, function () { 
$.ajax(options); 
}); 
if ($(document).queue(options.className).length == 1 && !ajaxRequest[options.className]) { 
ajaxRequest[options.className] = true; 
$(document).dequeue(options.className); 
} 
}; 
})(jQuery); 
 
第3中case 
应用场景: 比较典型的是autocomplete控件的操作,这个我们可以使用第2种情况的处理方法,但我们可能只需要最后次按键后返回的结果,这样利用第2种处理方法未免有些浪费。 
处理方法: 保留最后一次请求,cancel之前的请求。 
复制代码 代码如下: 
(function ($) { 
var jqXhr = {}; 
$.ajaxSingle = function (settings) { 
var options = $.extend({ className: 'DEFEARTNAME' }, $.ajaxSettings, settings); 
if (jqXhr[options.className]) { 
jqXhr[options.className].abort(); 
} 
jqXhr[options.className] = $.ajax(options); 
}; 
})(jQuery); 
 
对于这些case都是在多个ajax请求,响应时间不能控制的情况。下面是完整Demo代码。 
复制代码 代码如下: 
(function ($) { 
var jqXhr = {}, 
ajaxRequest = {}; 
$.ajaxQueue = function (settings) { 
var options = $.extend({ className: 'DEFEARTNAME' }, $.ajaxSettings, settings); 
var _complete = options.complete; 
$.extend(options, { 
complete: function () { 
if (_complete) 
_complete.apply(this, arguments); 
if ($(document).queue(options.className).length > 0) { 
$(document).dequeue(options.className); 
} else { 
ajaxRequest[options.className] = false; 
} 
} 
}); 
$(document).queue(options.className, function () { 
$.ajax(options); 
}); 
if ($(document).queue(options.className).length == 1 && !ajaxRequest[options.className]) { 
ajaxRequest[options.className] = true; 
$(document).dequeue(options.className); 
} 
}; 
$.ajaxSingle = function (settings) { 
var options = $.extend({ className: 'DEFEARTNAME' }, $.ajaxSettings, settings); 
if (jqXhr[options.className]) { 
jqXhr[options.className].abort(); 
} 
jqXhr[options.className] = $.ajax(options); 
}; 
})(jQuery); 
var ajaxSleep = (function () { 
var _settings = { 
type: 'GET', 
cache: false, 
success: function (msg) { 
var thtml = $('#txtContainer').html(); 
$('#txtContainer').html(thtml + "<br />" + msg); 
} 
}; 
return { 
get: function (seconds, mode, isAsync) { 
var mode = mode || 'ajax', 
isAsync = isAsync || false; 
$[mode]($.extend(_settings, { 
url: "ResponsePage.aspx?second=" + seconds, 
async: isAsync, 
className: 'GET' 
})); 
}, 
post: function (seconds, mode, isAsync) { 
var mode = mode || 'ajax', 
isAsync = isAsync || false; 
$[mode]($.extend(_settings, { 
type: 'POST', 
url: "PostPage.aspx", 
data: { second: seconds }, 
async: isAsync, 
className: 'POST' 
})); 
} 
}; 
} ()); 
var launch = function (settings) { 
$('#txtContainer').html(''); 
var mode = settings.mode, 
isAsync = settings.isAsync; 
ajaxSleep.get(12, mode, isAsync); 
ajaxSleep.get(10, mode, isAsync); 
ajaxSleep.get(8, mode, isAsync); 
ajaxSleep.post(6, mode, isAsync); 
ajaxSleep.post(4, mode, isAsync); 
ajaxSleep.post(2, mode, isAsync); 
} 
$(document).ready(function () { 
//第1种case 
$('#btnLaunchAsync').click(function () { 
launch({ isAsync: true }); 
}); 
//第2种case 
$('#btnLaunchSync').click(function () { 
launch({}); 
}); 
//第2种case 
$('#btnLaunchQueue').click(function () { 
launch({ mode: 'ajaxQueue', isAsync: true }); 
}); 
//第3种case 
$('#btnLaunchSingle').click(function () { 
launch({ mode: 'ajaxSingle', isAsync: true }); 
}); 
}); 
 
default.html 
复制代码 代码如下: 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml"> 
<head id="Head1" runat="server"> 
<title></title> 
<script src="/UploadFiles/2021-04-02/jquery.min.js"><script type="text/javascript" src="/UploadFiles/2021-04-02/default.js"></head> 
<body> 
<form id="form1" runat="server"> 
<input type="button" id="btnLaunchAsync" value="Launch Asynchronous Request" /> 
<input type="button" id="btnLaunchSync" value="Launch Synchronous Request" /> 
<input type="button" id="btnLaunchQueue" value="Launch Requested Queue" /> 
<input type="button" id="btnLaunchSingle" value="Launch Single Request" /> 
<div id="txtContainer"></div> 
</form> 
</body> 
</html> 
 
PostPage.aspx & ResponsePage.aspx 
复制代码 代码如下: 
//ResponsePage.aspx 
protected void Page_Load(object sender, EventArgs e) 
{ 
int seconds = int.Parse(Request.QueryString["second"]); 
Thread.Sleep(seconds*1000); 
Response.Write("GET: selpt for "+ seconds.ToString() +" sec(s)"); 
} 
//PostPage.aspx 
protected void Page_Load(object sender, EventArgs e) 
{ 
int seconds = int.Parse(Request.Form["second"]); 
Thread.Sleep(seconds * 1000); 
Response.Write("POST: selpt for " + seconds.ToString() + " sec(s)"); 
} 
 
后注: 个人能力有限,如有错误敬请指点。这些只是些根据一些特定情况下的处理,如果一个ajax请求能解决的问题切勿利用两个请求来处理,毕竟需要占用资源。我还是相信没有最好的方案,只有最适合的方案。