ajax异步文件上传，iframe方式
不是我写的，我看了他的，思路很明确：
实现思路：
在js脚本中动态创建form，动态创建form中的内容，将文件上传的内容以隐藏域的方式提交过去，然后写好回调等。
感觉思路不难，但是我写不出来，感觉需要对于url，http有一定了解，js也ok才可。
代码：
上传的js：
// 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] ); } } });
前台页面：
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Ajax File Uploader Plugin For Jquery</title> <script type="text/javascript" src="jquery.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) { $('#viewImg').attr('src',data.picUrl); }, 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> <img id="viewImg"> </body> </html>
后台servlet：
package upload; import java.io.File; import java.io.IOException; import java.io.PrintWriter; import java.util.Date; import java.util.List; import javax.servlet.ServletConfig; import javax.servlet.ServletContext; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.fileupload.FileItem; import org.apache.commons.fileupload.FileUploadException; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; /** * * 文件上传 具体步骤： 1）获得磁盘文件条目工厂 DiskFileItemFactory 要导包 2） 利用 request 获取 真实路径 * ，供临时文件存储，和 最终文件存储 ，这两个存储位置可不同，也可相同 3）对 DiskFileItemFactory 对象设置一些 属性 * 4）高水平的API文件上传处理 ServletFileUpload upload = new ServletFileUpload(factory); * 目的是调用 parseRequest（request）方法 获得 FileItem 集合list ， * * 5）在 FileItem 对象中 获取信息， 遍历， 判断 表单提交过来的信息 是否是 普通文本信息 另做处理 6） 第一种. 用第三方 提供的 * item.write( new File(path,filename) ); 直接写到磁盘上 第二种. 手动处理 * */ public class UploadProcessorServlet extends HttpServlet { private static final long serialVersionUID = 1L; // 保存文件的目录 private static String PATH_FOLDER = "/"; // 存放临时文件的目录 private static String TEMP_FOLDER = "/"; @Override public void init(ServletConfig config) throws ServletException { ServletContext servletCtx = config.getServletContext(); // 初始化路径 // 保存文件的目录 PATH_FOLDER = servletCtx.getRealPath("/upload"); // 存放临时文件的目录,存放xxx.tmp文件的目录 TEMP_FOLDER = servletCtx.getRealPath("/uploadTemp"); } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse * response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("utf-8"); // 设置编码 response.setCharacterEncoding("utf-8"); response.setContentType("text/html;charset=UTF-8"); // 获得磁盘文件条目工厂 DiskFileItemFactory factory = new DiskFileItemFactory(); // 如果没以下两行设置的话，上传大的 文件 会占用 很多内存， // 设置暂时存放的 存储室 , 这个存储室，可以和 最终存储文件 的目录不同 /** * 原理 它是先存到 暂时存储室，然后在真正写到 对应目录的硬盘上， 按理来说 当上传一个文件时，其实是上传了两份，第一个是以 .tem * 格式的 然后再将其真正写到 对应目录的硬盘上 */ factory.setRepository(new File(TEMP_FOLDER)); // 设置 缓存的大小，当上传文件的容量超过该缓存时，直接放到 暂时存储室 factory.setSizeThreshold(1024 * 1024); // 高水平的API文件上传处理 ServletFileUpload upload = new ServletFileUpload(factory); try { // 提交上来的信息都在这个list里面 // 这意味着可以上传多个文件 // 请自行组织代码 List<FileItem> list = upload.parseRequest(request); // 获取上传的文件 FileItem item = getUploadFileItem(list); // 获取文件名 String filename = getUploadFileName(item); // 保存后的文件名 String saveName = new Date().getTime() + filename.substring(filename.lastIndexOf(".")); // 保存后图片的浏览器访问路径 String picUrl = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+request.getContextPath()+"/upload/"+saveName; System.out.println("存放目录:" + PATH_FOLDER); System.out.println("文件名:" + filename); System.out.println("浏览器访问路径:" + picUrl); // 真正写到磁盘上 item.write(new File(PATH_FOLDER, saveName)); // 第三方提供的 PrintWriter writer = response.getWriter(); writer.print("{"); writer.print("msg:\"文件大小:"+item.getSize()+",文件名:"+filename+"\""); writer.print(",picUrl:\"" + picUrl + "\""); writer.print("}"); writer.close(); } catch (FileUploadException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } private FileItem getUploadFileItem(List<FileItem> list) { for (FileItem fileItem : list) { if(!fileItem.isFormField()) { return fileItem; } } return null; } private String getUploadFileName(FileItem item) { // 获取路径名 String value = item.getName(); // 索引到最后一个反斜杠 int start = value.lastIndexOf("/"); // 截取 上传文件的 字符串名字，加1是 去掉反斜杠， String filename = value.substring(start + 1); return filename; } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse * response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doGet(request, response); } }
文章来自：http://blog.csdn.net/thc1987/article/details/15341201
