form+iframe解决跨域上传文件

<form  id="form" name="form" enctype="multipart/form-data" method="post" target="hidden_frame">
<table style="border:0;width:100%;text-align:middle;">
<tr style="border:0;height:20px;width:100%;">
<td style="border:0;width:75px;height:20px;line-height:20px;">控件标识</td>
<td>
<input id="viewkey" name="viewkey" style="width:200px;" type="text" maxlength="300" placeholder="控件标识不能超过30个字。" class="easyui-validatebox" onkeyup="check()" required="true" missingMessage="参数名称不可为空."/>
</td>
</tr>
<tr>
<td>更新类型</td>
<td><input id="type" name="type" class="easyui-combobox" valueField="id" textField="text" panelHeight="auto"/></td>
</tr>
<tr>
<td>备注</td>
<td colspan=3>
<textarea id="remark" name="remark" onkeyup="check()" placeholder="备注不能超过300个字。" style="width:200px;height:80px;" ></textarea>
</td>
</tr>
<tr>
<td>资源文件：</td>
<td >
<input type="file" id="file" name="file" style="height:25px; width:200px;" onchange="fileChange(this);">
<input type="hidden" name="projectid" id="projectid" >
<input type="hidden" name="downimageconfigid" id="downimageconfigid" >
<input type="hidden" name="iskeychange" id="iskeychange" >
<input type="hidden" name="isnopic" id="isnopic" >
<iframe name="hidden_frame" id="hidden_frame" style="display:none"></iframe>
</td>
</tr>
<tr>
<td></td>
<td><div style="color: red; margin-top: 10px;">图片大小必须小于500K。</div></td>
</tr>
</table>
</form>

//添加对话框
function initDialog(){
$('#imgconf-dialog').dialog({
modal:true,
closable:false,
top: 20,
buttons:[{
id:'ut_add',
text:'确定',
iconCls:'icon-ok',
handler:function(){
//表单注册事件
$('#form').form({
success:function(data){//提交成功后的回调函数
if(data === '00'){
jqueryAlert('操作成功');
}
if(data === '03'){
$.messager.alert(global.title,'主键为空!','warning');
$('#ut_add').linkbutton('enable');
return;
}
if(data === '02'){
$.messager.alert(global.title,'已存在的控件标识!','warning');
$('#ut_add').linkbutton('enable');
return;
}
if(data === '01'){
$.messager.alert(global.title,'操作失败','warning');
$('#ut_add').linkbutton('enable');
return;
}
$('#imgconf-dialog').dialog('close');
//重新加载列表
getDataGridData();;
}
});

$('#ut_add').linkbutton('disable');

//【添加】
if(global.operatype == 'add'){
if($('#viewkey').val() == null || $('#viewkey').val() == ''){
$.messager.alert(global.title,'您尚未输入控件标识!','warning');
$('#ut_add').linkbutton('enable');
return;
}
if($('#file').val() == ''){
$.messager.alert(global.title,'您尚未上传图片!!','warning');
$('#ut_add').linkbutton('enable');
return;
}

//表单上传操作
$('#projectid').val(global.projectid);
$('#form').attr("action", global.web_path + "/grid/imgconf/addimgconf.do");
$("#form").submit();
$('#ut_add').linkbutton('disable');
} else {//【编辑】
//控件标识是否改变
var iskeychange;
if(selected.viewkey == $('#viewkey').val()){//控件标识没有改变
iskeychange = 'no';
}else{
iskeychange = 'yes';
}
var isnopic;
if($('#file').val() == ''){//是否有上传图片
snopic = 'yes';
}else{
isnopic = 'no';
}

//表单上传操作
$('#projectid').val(global.projectid);
$('#downimageconfigid').val(selected.downimageconfigid);
$('#iskeychange').val(iskeychange);
$('#isnopic').val(isnopic);
$('#form').attr("action",global.web_path + "/grid/imgconf/modimgconf.do");
$("#form").submit(); ;
$('#ut_add').linkbutton('disable');
}
}
},{
id:'ut_close',
text:'退出',
handler:function(){
$('#ut_add').linkbutton('enable');
$('#imgconf-dialog').dialog('close');
$('#uploadify').uploadifyClearQueue();
}
}]
});
}

//重置
function reset(){
$('#ut_add').linkbutton('enable');
var target = $('#file');
if(global.operatype == 'mod'){
$('#imgconf-dialog').dialog('setTitle','修改');
$('#viewkey').val(selected.viewkey);
$('#type').combobox('setValue', selected.type);
$('#remark').val(selected.remark);
$('#imgconf-dialog').dialog('open');
//文件上传清空
deleteFile('file');
}else {
$('#imgconf-dialog').dialog('setTitle','添加');
$('#viewkey').val('');
$('#remark').val('');

//文件上传清空
deleteFile('file');
}
}

/**
* 文本区域限制长度
*/
function check(){
var content = $('#remark').val();
len = content.length;
var maxlen = 300;
if(len > maxlen){
alert("字数太长，已被截断为300字!");
$('#remark').val(content.substr(0,maxlen));
}
}

// input type='file'置位操作
function deleteFile(file){
var ie = (navigator.appVersion.indexOf("MSIE")!=-1);//IE
var ff = (navigator.userAgent.indexOf("Firefox")!=-1);//Firefox
if(ie){
refreshUploader($("input[name="+file+"]")[0]);
}
else{
$("input[name="+file+"]").attr("value","");
}
}
function refreshUploader(file){
var file2= file.cloneNode(false);
file2.onchange= file.onchange;
file.parentNode.replaceChild(file2,file);
}

//检测文件大小和类型
function fileChange(target){
//检测上传文件的类型
if(!(/(?:jpg|gif|png|jpeg)$/i.test(target.value))) {
alert("只允许上传jpg|gif|png|jpeg格式的图片");
if(window.ActiveXObject) {//for IE
target.select();//select the file ,and clear selection
document.selection.clear();
} else if(window.opera) {//for opera
target.type="text";target.type="file";
} else target.value="";//for FF,Chrome,Safari
return;
} else {
return; //alert("ok");//or you can do nothing here.
}

//检测上传文件的大小
var isIE = /msie/i.test(navigator.userAgent) && !window.opera;
var fileSize = 0;
if (isIE && !target.files){
var filePath = target.value;
var fileSystem = new ActiveXObject("Scripting.FileSystemObject");
var file = fileSystem.GetFile (filePath);
fileSize = file.Size;
} else {
fileSize = target.files[0].size;
}
var size = fileSize / 1024;
if(size>(500)){
alert("文件大小不能超过500KB");
if(window.ActiveXObject) {//for IE
target.select();//select the file ,and clear selection
document.selection.clear();
} else if(window.opera) {//for opera
target.type="text";target.type="file";
} else {
target.value="";//for FF,Chrome,Safari
}
return;
}else{
return;
}
}

/**
* 添加下载图片配置
* @throws IOException
*/
@RequestMapping(value = "/grid/imgconf/addimgconf",method = {RequestMethod.POST, RequestMethod.GET},produces = {"text/html;charset=UTF-8"})
@ResponseBody
public String addImgConf(HttpServletRequest
request, HttpServletResponse response, BindException errors) throws IOException{
String m = "00";
MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
Map<String, MultipartFile> fileMap = multipartRequest.getFileMap();
response.setHeader("Access-Control-Allow-Origin", "*");
String projectid = Function.dealNull(multipartRequest.getParameter("projectid"));
String viewKey = Function.dealNull(multipartRequest.getParameter("viewkey"));
String type = Function.dealNull(multipartRequest.getParameter("type"));
String remark = Function.dealNull(multipartRequest.getParameter("remark"));
try {
//唯一性判断
int size = imgConfService.getImgConfsCount(Constants.DEF_STRING_NULL, projectid, viewKey, Constants.STATUS_ON);
if(size > 0){
m = "02";
logger.info("已存在的控件标识!");
return "<textarea>" + m + "</textarea>";
}
//上传图片
Map<String, String> picInfo = imgConfService.uploadImage(fileMap);
imgConfService.addImgConf(UUID.randomUUID().toString(), projectid, viewKey, type, remark, picInfo.get("URL"), Constants.STATUS_ON);
m = "00";
logger.info("添加下载图片配置成功！");
} catch (Exception e) {
m = "01";
logger.error("添加下载图片配置失败" ,e);
}