异常-----springmvc + ajaxfileupload解决ajax不能异步上传图片的问题。java.lang.ClassCastException: org.apache.catalina.connector.RequestFacade cannot be cast to org.springframework.web.multipart.

说明这个问题产生的原因主要是form表单上传图片的时候必须是Content-Type:"multipart/form-data，这种格式的，但是ajax在页面不刷新的情况下去加载的时候只会把表单中name的值给传过去，而其它的则不会。application/x-www-form-urlencoded ： <form encType=””>中默认的encType，form表单数据被编码为key/value格式发送到服务器（表单默认的提交数据的格式）。multipart/form-data ：需要在表单中进行文件上传时，就需要使用该格式。但是如果这时候即使在form表头加上enctype=multipart/form-data这个属性，通过ajax传递url也不会被传递过去的。假如用MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;这种方式获得multipartRequest ，后台要报，ava.lang.ClassCastException: org.apache.catalina.connector.RequestFacade cannot be cast to org.springframework.web.multipart.MultipartHttpServletRequest 。假如用这种方式获得用其他方法也可能报出enctype=multipart/form-data转化异常，因为这时候看页面的请求头可以看出这时候传过来的是application/x-www-form-urlencoded 默认的，解决方法就是下面的。

1，js/ajaxfileupload.js

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)
{
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;
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" )
eval( "data = " + data );
// evaluate scripts within html
if ( type == "html" )
jQuery("<div>").html(data).evalScripts();

return data;
}
})

2，html页面

$(function(){
var date= new Date();
var applyId=date.getTime();
$("#applyId").val(applyId);
});
function uploadBtn(){
$("#upload").click();
}

//图片预览
function previewImg(imgFile){
console.log(imgFile);//这里打印出是整个input标签
var extension = imgFile.value.substring(imgFile.value.lastIndexOf("."),imgFile.value.length);//扩展名
extension = extension.toLowerCase();//把文件扩展名转换为小写
if ((extension!='.jpg')&&(extension!='.gif')&&(extension!='.jpeg')&&(extension!='.png')&&(extension!='.bmp')){
layer.msg("对不起，系统仅支持标准格式的照片，请您调整格式后重新上传，谢谢 !");
$("#yushow").focus();//将焦点定位在文件上传的按钮上，可以直接按确定键再次触发
}else{
var path;//预览地址
if(document.all){//IE
imgFile.select();
path = document.selection.createRange().text;
}else{//火狐，谷歌
path = window.URL.createObjectURL(imgFile.files[0]);
}
$("#yushow").attr("src",path);//设置预览地址
}
}

function saveBn(){

var applyid=$("#applyId").val();
alert(applyid);
alert("2"+$("#upload").val());
$.ajaxFileUpload({
url: '${rc.contextPath}/wxFfanApply1.htm?method=save',
secureuri:false,
type: 'POST',
fileElementId:"upload",
dataType: 'text',
data: {

"applyId": $("#applyId").val(),
"upload":$("#upload").val(),
"zhucehao":$("#zhucehao").val(),
"companyName":$("#companyName").val(),
"companylegal":$("#companylegal").val(),
"companyScope":$("#companyScope").val(),
"detaileAddress":$("#detaileAddress").val(),
"validDate": $("#validDate").val(),
"wxOpenId":"123",
"wxModuleType":"456"

},
success: function (info, status)
{
var data=getResult(info);
$(document).unmask();
if(data.success){
var f=data.obj;
var hans="showFileImg('"+f.fssId+"','"+f.fileSourceName+"')";
$("#filelink" + fileType).html("<a href='javascript:void(0)' onclick=\""+hans+"\">"+f.fileName+"</a>");
} else {
var msg = data.msg;
alert('系统反馈：'+msg);
}
},
error: function (data, status, e)
{
$(document).unmask();
//location.href ="/intra/crm/merchantMgr/editUploadFile.htm?method=list&merchantCode="+$("#merchantCode").val()+"&applyId="+applyId;
alert("网络异常,请稍后重试---->"+data.responseText);
}
});

}

3，java代码

public void UploadFile1(HttpServletRequest request,HttpServletResponse response,String applyId) {
AjaxJson json = new AjaxJson();
MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
String fileElementId = request.getParameter("fileElementId");
if (StringUtils.isEmpty(fileElementId))
{
fileElementId = "upload";
}
MultipartFile inputFile = multipartRequest.getFile(fileElementId);

Object[] object = new Object[] { inputFile };
if (CommonUtil.isMultiEmpty(object)) {
json.setSuccess(false);
json.setMsg("参数非法...请走正常流程提交");
} else {
ApplyFileDto dto = new ApplyFileDto();
dto.setApplyId(applyId);

// dto.setExpireDate(expireDate);
dto.setChannelCode("crm");
dto.setFileSorceName(inputFile.getOriginalFilename());
try {
ApplyFile model = null;
try {
model = fileProcessManage.uploadFile(inputFile,dto);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
json.setObj(model);
} catch (IllegalArgumentException e) {
json.setSuccess(false);
json.setMsg(e.getMessage());
}

if (BrowserUtils.isIE(request)) {
response.setContentType("text/plain;charset=utf-8");
}
}

}

另一种解决方法见，form表单的action提交写到js中来。同时onclick事件也写在js中来。不用ajax直接用action提交就可以了。