由于我们项目的jsp也页面访问后台都是无form的，统统都是ajax异步提交参数数据，所以我就百度着通过ajaxfileupload.js插件实现了
1.前台代码
<script type="text/javascript" src="jquery-1.11.1.min.js"></script> <script type="text/javascript" src="ajaxfileupload.js"></script> <script type="text/javascript"> function ajaxFileUpload() { $.ajaxFileUpload({ url : 'upload', secureuri : false, fileElementId : 'fileToUpload', dataType : 'json', data : {username : $("#username").val()}, success : function(data, status) { }, error : function(data, status, e) { alert('上传出错'); } }) return false; } </script> </head> <body> <h1>选择图片后,点击按钮上传</h1> <input id="fileToUpload" type="file" size="45" name="fileToUpload" class="input"> <button class="button" onclick="ajaxFileUpload()">上传</button> <br> </body>
ps: 需要注意ajax的fileElementId的值对应文件域的id和name；
插件本身不支持多文件上传，但我们项目的需求是多文件上传的，所以我百度了好久修改了插件最终支持了，修改后的插件源码见文章最后：
修改后的ajax fileElementId参数
这样即可多文件上传：（image1,和image2两个文件域）
fileElementId:['image1','image2'], //文件域id值 name值
2.我们项目没有框架所以我贴下servlet的后台接收（全贴了，有啰嗦的地方大家见谅，自己删除吧）
String img_path = request.getSession().getServletContext().getRealPath("/");
String p = "huiy";// 作为一个标志符，如果p不等于1，则图片命名为pkey_(n++),否则随机生成
Map<String, Object> filenamemap = FileUploadUtil.upload(request,img_path, "image",p);
public static Map<String, Object> upload(HttpServletRequest request,String path,String type, String p) { // 最大文件大小 //long maxSize = 1048576;// 1M=1024kb(千字节)=1048576b字节 boolean flag = true; String pkey = ""; // 定义允许上传的文件扩展名 HashMap<String, String> extMap = new HashMap<String, String>(); extMap.put("image", "gif,jpg,jpeg,png,bmp"); extMap.put("flash", "swf,flv"); extMap.put("media", "swf,flv,mp3,wav,wma,wmv,mid,avi,mpg,asf,rm,rmvb"); extMap.put("file", "doc,docx,xls,xlsx,ppt,htm,html,txt,zip,rar,gz,bz2"); path=path+type; File dirFile = new File(path); if (!dirFile.exists()) { dirFile.mkdirs(); } DiskFileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); List<String> filenamelist = new ArrayList<String>(); try { List<FileItem> list = upload.parseRequest(request); int n = 1; for (FileItem item : list) { // 如果获取的 表单信息是普通的 文本 信息 if (item.isFormField()) {// 判断是否是普通文本 String name = item.getFieldName(); // 获取上传时候的data数据（普通数据） String value = item.getString(); if ("pkey".equals(name)) { pkey = value; } } else { /* * // 检查文件大小 if (item.getSize() > maxSize) { continue; } */ /** * 以下三步，主要获取 上传文件的名字 */ // 获取图片名 String fileName = item.getName(); // 检查扩展名 String fileExt = fileName.substring( fileName.lastIndexOf(".") + 1).toLowerCase(); if (!Arrays.<String> asList(extMap.get("image").split(",")) .contains(fileExt)) { continue; } SimpleDateFormat df = new SimpleDateFormat("yyyyMMddHHmmss"); String base64Name = df.format(new Date()) + "_" + new Random().nextInt(1000); if (!"1".equals(p)) { base64Name = p + pkey + "_" + n; } String filename = base64Name + "." + fileExt; OutputStream out = new FileOutputStream(new File(path, filename)); InputStream in = item.getInputStream(); int length = 0; byte[] buf = new byte[1024]; while ((length = in.read(buf)) != -1) { out.write(buf, 0, length); } in.close(); out.close(); filenamelist.add(type+"/"+filename); n++; } } } catch (Exception e) { flag = false; e.printStackTrace(); } Map<String, Object> map = new HashMap<String, Object>(); map.put("flag", flag); map.put("pkey", pkey); map.put("filenamelist", filenamelist); return map; }
3.页面访问图片
由于本地图片上传到了本地服务器所以本地访问时为：
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+request.getContextPath();加上图片的路径
ps: ①ajaxfileupload.js 的本质是先创建个form表单，提交后再把表单删除。
②ajaxfileupload.js 网上下载的插件有很多错误，需要修正
附带我修改后的插件（ajaxfileupload.js）源码：
// JavaScript Document jQuery.extend({ createUploadIframe: function(id, uri) { //create frame var frameId = 'jUploadFrame' + id; if(window.ActiveXObject) { //var io = document.createElement('<iframe id="' + frameId + '" name="' + frameId + '" />'); if(jQuery.browser.version=="9.0" || jQuery.browser.version=="10.0"){ var io = document.createElement('iframe'); io.id = frameId; io.name = frameId; }else if(jQuery.browser.version=="6.0" || jQuery.browser.version=="7.0" || jQuery.browser.version=="8.0"){ var io = document.createElement('<iframe id="' + frameId + '" name="' + frameId + '" />'); if(typeof uri== 'boolean'){ io.src = 'javascript:false'; } else if(typeof uri== 'string'){ io.src = uri; } } }else { var io = document.createElement('iframe'); io.id = frameId; io.name = frameId; } io.style.position = 'absolute'; io.style.top = '-1000px'; io.style.left = '-1000px'; document.body.appendChild(io); return io; }, 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>'); var oldElement = jQuery('#' + fileElementId); var newElement = jQuery(oldElement).clone(); jQuery(oldElement).attr('id', fileId); jQuery(oldElement).before(newElement); jQuery(oldElement).appendTo(form); //add data if(data) { for (var i in data) { $('<input type="hidden" name="' + i + '" value="' + data[i] + '" />').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 = s.id; //var id = s.fileElementId; var form = jQuery.createUploadForm(id, s.fileElementId,s.data); var io = jQuery.createUploadIframe(id, s.secureuri); var frameId = 'jUploadFrame' + id; var formId = 'jUploadForm' + id; if( s.global && ! jQuery.active++ ){ // Watch for a new set of requests jQuery.event.trigger( "ajaxStart" ); } var requestDone = false; // Create the request object var xml = {}; if( s.global ){ jQuery.event.trigger("ajaxSend", [xml, s]); } var uploadCallback = function(isTimeout){ // Wait for a response to come back 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( s.success ){ // ifa local callback was specified, fire it and pass it the data s.success( data, status ); }; if( s.global ){ // Fire the global callback jQuery.event.trigger( "ajaxSuccess", [xml, s] ); }; } else{ jQuery.handleError(s, xml, status); } } catch(e){ status = "error"; jQuery.handleError(s, xml, status, e); }; if( s.global ){ // The request was completed jQuery.event.trigger( "ajaxComplete", [xml, s] ); }; // Handle the global AJAX counter if(s.global && ! --jQuery.active){ jQuery.event.trigger("ajaxStop"); }; 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(){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){ form.encoding = 'multipart/form-data'; }else{ form.enctype = 'multipart/form-data'; } jQuery(form).submit(); } catch(e){ jQuery.handleError(s, xml, null, e); } /*if(window.attachEvent){ document.getElementById(frameId).attachEvent('onload', uploadCallback); } else{ document.getElementById(frameId).addEventListener('load', uploadCallback, false); } */ jQuery('#' + frameId).load(uploadCallback); return {abort: function () {}}; }, uploadHttpData: function( r, type ) { var data = !type; data = type == "xml" || data ? r.responseXML : r.responseText; // ifthe type is "script", eval it in global context if( type == "script" ){ jQuery.globalEval( data ); } // Get the JavaScript object, ifJSON is used. if( type == "json" ){ 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, xml, status, e ) { // If a local callback was specified, fire it if ( s.error ) s.error( xml, status, e ); // Fire the global callback if ( s.global ) jQuery.event.trigger( "ajaxError", [xml, s, e] ); }*/ 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] ); } } });
