springmvc+ajaxFileUpload上传文件(前后台彻底分离的情况下)

首先是导入jar包:

jQuery.extend({

createUploadIframe: function (id, uri) {
//create frame
var frameId = 'jUploadFrame' + id;
var iframeHtml = '<iframe id="' + frameId + '" name="' + frameId + '" style="position:absolute; top:-9999px; left:-9999px"';
if (window.ActiveXObject) {
if (typeof uri == 'boolean') {
iframeHtml += ' src="' + 'javascript:false' + '"';

}
else if (typeof uri == 'string') {
iframeHtml += ' src="' + uri + '"';

}
}
iframeHtml += ' />';
jQuery(iframeHtml).appendTo(document.body);

return jQuery('#' + frameId).get(0);
},
createUploadForm: function (id, fileElementId, data) {
//create form
var formId = 'jUploadForm' + id;
var fileId = 'jUploadFile' + id;
var form = jQuery('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>');
if (data) {
for (var i in data) {
if (data[i].name != null && data[i].value != null) {
jQuery('<input type="hidden" name="' + data[i].name + '" value="' + data[i].value + '" />').appendTo(form);
} else {
jQuery('<input type="hidden" name="' + i + '" value="' + data[i] + '" />').appendTo(form);
}
}
}
var oldElement = jQuery('#' + fileElementId);
var newElement = jQuery(oldElement).clone();
jQuery(oldElement).attr('id', fileId);
jQuery(oldElement).before(newElement);
jQuery(oldElement).appendTo(form);

//set attributes
jQuery(form).css('position', 'absolute');
jQuery(form).css('top', '-1200px');
jQuery(form).css('left', '-1200px');
jQuery(form).appendTo('body');
return form;
},

ajaxFileUpload: function (s) {
// TODO introduce global settings, allowing the client to modify them for all requests, not only timeout
s = jQuery.extend({}, jQuery.ajaxSettings, s);
var id = new Date().getTime()
var form = jQuery.createUploadForm(id, s.fileElementId, (typeof (s.data) == 'undefined' ? false : s.data));
var io = jQuery.createUploadIframe(id, s.secureuri);
var frameId = 'jUploadFrame' + id;
var formId = 'jUploadForm' + id;
// Watch for a new set of requests
if (s.global && !jQuery.active++) {
jQuery.event.trigger("ajaxStart");
}
var requestDone = false;
// Create the request object
var xml = {}
if (s.global)
jQuery.event.trigger("ajaxSend", [xml, s]);
// Wait for a response to come back
var uploadCallback = function (isTimeout) {
var io = document.getElementById(frameId);
try {
if (io.contentWindow) {
xml.responseText = io.contentWindow.document.body ? io.contentWindow.document.body.innerHTML : null;
xml.responseXML = io.contentWindow.document.XMLDocument ? io.contentWindow.document.XMLDocument : io.contentWindow.document;

} else if (io.contentDocument) {
xml.responseText = io.contentDocument.document.body ? io.contentDocument.document.body.innerHTML : null;
xml.responseXML = io.contentDocument.document.XMLDocument ? io.contentDocument.document.XMLDocument : io.contentDocument.document;
}
} catch (e) {
jQuery.handleError(s, xml, null, e);
}
if (xml || isTimeout == "timeout") {
requestDone = true;
var status;
try {
status = isTimeout != "timeout" ? "success" : "error";
// Make sure that the request was successful or notmodified
if (status != "error") {
// process the data (runs the xml through httpData regardless of callback)
var data = jQuery.uploadHttpData(xml, s.dataType);
// If a local callback was specified, fire it and pass it the data
if (s.success)
s.success(data, status);

// Fire the global callback
if (s.global)
jQuery.event.trigger("ajaxSuccess", [xml, s]);
} else
jQuery.handleError(s, xml, status);
} catch (e) {
status = "error";
jQuery.handleError(s, xml, status, e);
}

// The request was completed
if (s.global)
jQuery.event.trigger("ajaxComplete", [xml, s]);

// Handle the global AJAX counter
if (s.global && ! --jQuery.active)
jQuery.event.trigger("ajaxStop");

// Process result
if (s.complete)
s.complete(xml, status);

jQuery(io).unbind()

setTimeout(function () {
try {
jQuery(io).remove();
jQuery(form).remove();

} catch (e) {
jQuery.handleError(s, xml, null, e);
}

}, 100)

xml = null

}
}
// Timeout checker
if (s.timeout > 0) {
setTimeout(function () {
// Check to see if the request is still happening
if (!requestDone) uploadCallback("timeout");
}, s.timeout);
}
try {

var form = jQuery('#' + formId);
jQuery(form).attr('action', s.url);
jQuery(form).attr('method', 'POST');
jQuery(form).attr('target', frameId);
if (form.encoding) {
jQuery(form).attr('encoding', 'multipart/form-data');
}
else {
jQuery(form).attr('enctype', 'multipart/form-data');
}
jQuery(form).submit();

} catch (e) {
jQuery.handleError(s, xml, null, e);
}

jQuery('#' + frameId).load(uploadCallback);
return { abort: function () { } };

},

uploadHttpData: function (r, type) {
var data = !type;
if (!type)
data = r.responseText;
if (type == "xml")
data = r.responseXML;
//data = type == "xml" || data ? r.responseXML : r.responseText;
// If the type is "script", eval it in global context
if (type == "script")
jQuery.globalEval(data);
// Get the JavaScript object, if JSON is used.
if (type == "json") {
////////////Fix the issue that it always throws the error "unexpected token '<'"///////////////
data = r.responseText;
var start = data.indexOf(">");
if (start != -1) {
var end = data.indexOf("<", start + 1);
if (end != -1) {
data = data.substring(start + 1, end);
}
}
///////////////////////////////////////////////////////////////////////////////////////////////
eval("data = " + data);
}
// evaluate scripts within html
if (type == "html")
jQuery("<div>").html(data).evalScripts();

return data;
},

handleError: function (s, xhr, status, e) {
// If a local callback was specified, fire it
if (s.error) {
s.error.call(s.context || s, xhr, status, e);
}

// Fire the global callback
if (s.global) {
(s.context ? jQuery(s.context) : jQuery.event).trigger("ajaxError", [xhr, s, e]);
}
}
})

View Code
html代码:

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>上传页面三</title>
<script type="text/javascript" src="static/js/jquery-1.7.2.js"></script>
<script type="text/javascript" src="static/js/ajaxfileupload.js"></script>
</head>

<body>
<h2>JQuery ajaxfileupload文件上传</h2>
<div id="loading" style="display: none;">正在上传.....</div>
用户信息：
<br /> 姓名：
<input id="name" name="name" type="text">
<br /> 附件：
<input id="fileToUpload" name="file" type="file" class="input">
<br />
<input type="button" onclick="ajaxFileUpload()" value="上传">
<br />

<script type="text/javascript">
function ajaxFileUpload() {
$('#loading').show();
$.ajaxFileUpload({
url : 'mvc/upload.g',
secureuri : false,
fileElementId : 'fileToUpload',
dataType : 'json',//此时指定的是后台需要返回json字符串,前端自己解析,可以注释掉.后台直接返回map
data : {
name : $('#name').val()
},
success : function(data, status) {
alert("success");
console.log(data);
$('#loading').hide();
},
error : function(data, status, e) {
$('#loading').hide();
//这里处理的是网络异常，返回参数解析异常，DOM操作异常
alert("上传发生异常");
}
})
}
</script>
</body>
</html>

好,结束.

当你程序跑起来的时候,打开控制台你是看不到ajax提交请求的.因为ajaxFileupload.js上传的 原理是:form表单+iframe提交的.

服务器端返回的数据最终会进入到iframe里面的.通过修改ajaxFileUpload.js把这个数据从ifram中解析出来.

这个过程可以在success里加个alert,阻止脚本执行,来观察到.当success执行完毕后,form和iframe被删除.

可以结合前面的上传博客来更好地理解这里.