Ajax应用之文件上传

来源：互联网发布：2016好听的网络歌曲编辑：程序博客网时间：2024/06/05 20:06

文件上传是一个很费时的任务，经常需要用户进行长时间等待，为了让用户在等待过程中，及时了解上传进度，可以在进行文件上传时，显示上传进度条。示例：

index.jsp：

<%@ page language="java" import="java.util.*"contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%><!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"><script language="JavaScript" src="JS/AjaxRequest.js"></script><script language="JavaScript">//处理文件上传function deal(form) {form.submit();window.setInterval("getProgress()", 500);}//获取进度方法function getProgress() {var loader = new net.AjaxRequest("showProgress.jsp?nocache="+ new Date().getTime(), dealProgress, onerror, "GET");}//处理获取进度结果function dealProgress() {var h = this.req.responseText;h=h.replace("^s/g","");document.getElementById("progressPercent").style.display="";document.getElementById("progressPercent").innerHTML=h+"%";document.getElementById("progressBar").style.display="block";document.getElementById("imgProgress").width=h*(255/100);}function onerror() {alert("文件上传出错！");}</script><title>起始页</title></head><body><form method="post" action="UploadServlet?action=uploadFile"name="form1" enctype="multipart/form-data">请选择上传的文件：<input name="file" type="file" size="42"> <imgsrc="images/upload.jpg" width="61" height="23" onclick="deal(form1)"></form><div id="progressBar" class="progressBar" align="left"><img src="images/progressBar.jpg" width="0" height="13"id="imgProgress"></div><span id="progressPercent" style="width: 40px; display: none;">0%</span></body></html>

UploadServlet：

package com.home.web.servlet;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.util.Iterator;import java.util.List;import javax.servlet.ServletException;import javax.servlet.annotation.MultipartConfig;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import org.apache.commons.fileupload.FileItem;import org.apache.commons.fileupload.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;/** * Servlet implementation class UploadServlet */@WebServlet("/UploadServlet")@MultipartConfig(location = "e:/tmp")public class UploadServlet extends HttpServlet {private static final long serialVersionUID = 1L;           /**     * @see HttpServlet#HttpServlet()     */    public UploadServlet() {        super();    }/** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {}/** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        uploadFile(request, response);}    public void uploadFile(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        response.setContentType("text/html;charset=UTF-8");        response.setCharacterEncoding("UTF-8");        HttpSession session = request.getSession();        session.setAttribute("progressBar", 0);        String error = "";        int maxSize = 50 * 1024 * 1024;        DiskFileItemFactory factory = new DiskFileItemFactory();        ServletFileUpload upload = new ServletFileUpload(factory);        try {            List items = upload.parseRequest(request);            Iterator it = items.iterator();            while (it.hasNext()) {                FileItem item = (FileItem) it.next();                if (!item.isFormField()) {                    if (!"".equals(item.getName()) && item.getName() != null) {                        long upFileSize = item.getSize();                        String fileName = item.getName();                        if (upFileSize > maxSize) {                            error = "文件不能超过50M";                            break;                        }                        File tempFile = new File(fileName);                        File file = new File(request.getRealPath("/upload"), tempFile.getName());                        System.out.println(file.getAbsolutePath());                        InputStream is = item.getInputStream();                        int len = 0;                        byte[] b = new byte[1024];                        double percent = 0;                        FileOutputStream fos = new FileOutputStream(file);                        while ((len = is.read(b)) != -1) {                            percent += len / (double) upFileSize * 100D;                            fos.write(b, 0, len);                            session.setAttribute("progressBar", Math.round(percent));                        }                        fos.close();                        Thread.sleep(1000);                    } else {                        error = "没有选择上传文件";                    }                }            }        } catch (Exception e) {            e.printStackTrace();            error = "文件上传出现错误：" + e.getMessage();        }        if (!"".equals(error)) {            request.setAttribute("error", error);            request.getRequestDispatcher("error.jsp").forward(request, response);        } else {            request.setAttribute("result", "文件上传成功！");            request.getRequestDispatcher("result.jsp").forward(request, response);        }    }}

showProgress.jsp：

<%@ 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>Insert title here</title></head><body>${progressBar}</body></html>

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