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
时间： 2024-10-22 20:56:24