基于commons-fileupload组件的实施上传下载与删除

来源：互联网发布：淘宝卖家被投诉卖假货编辑：程序博客网时间：2024/06/04 00:43

作者：郭 qq450511278

1. 首先把javacommons-fileupload-1.2.1.jar和commons-io-1.4.jar两个包通过MyEclipse导入到项目工程里。

2. 建立FileUpload.java的Servlet类。

package com.web.server.servlet;

import java.io.File;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.Iterator;

import java.util.List;

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.FileUploadBase.SizeLimitExceededException;

import org.apache.commons.fileupload.disk.DiskFileItemFactory;

import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class FileUpload extends HttpServlet {

public FileUpload() {

super();

}

public void destroy() {

super.destroy(); // Just puts "destroy" string in log

}

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doPost(request, response);

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

final String appRealPath = this.getServletContext().getRealPath("/"); // 获取webapp的物理路径

final long MAX_SIZE = 3 * 1024 * 1024; // 设置上传文件最大为 3M

final String[] allowedExt = new String[] { "jpg", "jpeg", "gif", "txt",

"doc", "docx","pdf", "mp3", "wma", "jar" }; // 允许上传的文件格式的列表

response.setContentType("text/html");

response.setCharacterEncoding("UTF-8"); // 设置字符编码为UTF-8, 这样支持汉字显示

// 实例化一个硬盘文件工厂,用来配置上传组件ServletFileUpload

DiskFileItemFactory dfif = new DiskFileItemFactory();

dfif.setSizeThreshold(4096); // 设置上传文件时用于临时存放文件的内存大小,这里是4K.多于的部分将临时存在硬盘

dfif.setRepository(new File(appRealPath + "FilesUploadTemp//"));

// 设置存放临时文件的目录,web根目录下的ImagesUploadTemp目录

// 用以上工厂实例化上传组件

ServletFileUpload sfu = new ServletFileUpload(dfif);

sfu.setSizeMax(MAX_SIZE); // 设置最大上传尺寸

PrintWriter out = response.getWriter();

// 从request得到所有上传域的列表

List fileList = null;

try {

fileList = sfu.parseRequest(request);

} catch (FileUploadException e) {// 处理文件尺寸过大异常

if (e instanceof SizeLimitExceededException) {

out.println("文件尺寸超过规定大小:" + MAX_SIZE + "字节<p />");

out.println("<a href=/" " + request.getContextPath()

+ "/server_upload.jsp" + " /" target=/"_top/">返回</a>");

return;

}

e.printStackTrace();

}

// 没有文件上传

if (fileList == null || fileList.size() == 0) {

out.println("请选择上传文件<p />");

out.println("<a href=/" " + request.getContextPath()

+ "/server_upload.jsp" + " /" target=/"_top/">返回</a>");

return;

}

// 得到所有上传的文件

Iterator fileItr = fileList.iterator();

// 循环处理所有文件

while (fileItr.hasNext()) {

FileItem fileItem = null;

String path = null;

long size = 0;

// 得到当前文件

fileItem = (FileItem) fileItr.next();

// 忽略简单form字段而不是上传域的文件域(<input type="text" />等)

if (fileItem == null || fileItem.isFormField()) {

continue;

}

// 得到文件的完整路径

path = fileItem.getName();

// 得到文件的大小

size = fileItem.getSize();

if ("".equals(path) || size == 0) {

out.println("请选择上传文件<p />");

out.println("<a href=/" " + request.getContextPath()

+ "/server_upload.jsp" + " /" target=/"_top/">返回</a>");

return;

}

// 得到去除路径的文件名

String t_name = path.substring(path.lastIndexOf("//") + 1);

// 得到文件的扩展名(无扩展名时将得到全名)

String t_ext = t_name.substring(t_name.lastIndexOf(".") + 1);

// 拒绝接受规定文件格式之外的文件类型

int allowFlag = 0;

int allowedExtCount = allowedExt.length;

for (; allowFlag < allowedExtCount; allowFlag++) {

if (allowedExt[allowFlag].equals(t_ext))

break;

}

if (allowFlag == allowedExtCount) {

out.println("请上传以下类型的文件<p />");

for (allowFlag = 0; allowFlag < allowedExtCount; allowFlag++)

out.println("*." + allowedExt[allowFlag]

+ "   ");

out.println("<a href=/" " + request.getContextPath()

+ "/server_upload.jsp" + " /" target=/"main/">返回</a>");

return;

}

* 根据系统时间生成上传后保存的文件名

//long now = System.currentTimeMillis();

// 根据系统时间生成上传后保存的文件名

//String prefix = String.valueOf(now);//转为字符串

//System.out.println("servlet"+prefix);

// 保存的最终文件完整路径,保存在web根目录下的FilesUploaded目录下

/*String u_name = appRealPath + "FilesUploaded//" + prefix + "."

+ t_ext;

String u_name = appRealPath + "FilesUploaded//" + path ;

try {

// 保存文件

fileItem.write(new File(u_name));

/*out.println("文件上传成功. 已保存为: " + prefix + "." + t_ext

+ "   文件大小: " + size + "字节<p />");

out.println("文件上传成功. 已保存为: " + path

+ "   文件大小: " + size + "字节<p />");

out.println("恭喜管理员资料上传成功！");

} catch (Exception e) {

e.printStackTrace();

}

public void init() throws ServletException {

}

3. 编写好Servlet之后对项目中的web.xml文件进行配置，映射Servlet的正确路径。

<servlet-name>FileUpload</servlet-name>

<servlet-class>com.web.server.servlet.FileUpload</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>FileUpload</servlet-name>

<url-pattern>/servlet/FileUpload</url-pattern>

</servlet-mapping>

4. 最后进行视图层的JSP页面的编写。如下展示上传功能模块表单部分的代码

server_upload.jsp：

<%@ page language="java" import="java.util.*" pageEncoding="GB18030"%>

<%@ page import="com.web.server.user.*"%>

<%@page import="java.io.File"%>

<!-- 此处我使用了Jakarta的commons-fileupload-1.2.1.jar和commons-io-1.4.jar上传组件并且编写了上传使用的servlet:FileUpload.java

-->

<html>

<head>

<!--

a{ text-decoration: none; color: #000000 }

a:hover{ text-decoration: underline }

body{ scrollbar-base-color: #F3F6FA; scrollbar-arrow-color: #4D76B3; font-size: 12px; background-color: #ffffff }

table{ font: 12px Verdana,Tahoma; color: #000000 }

input,select,textarea{ font: 11px Verdana,Tahoma; color: #000000; font-weight: normal; background-color: #F3F6FA }

select{ font: 11px Verdana,Tahoma; color: #000000; font-weight: normal; background-color: #F3F6FA }

.nav{ font: 12px Verdana,Tahoma; color: #000000; font-weight: bold }

.nav a{ color: #000000 }

.header{ font: 11px Verdana,Tahoma; color: #000000; font-weight: bold; background-image: url("images/green/bg01.gif") }

.header a{ color: #FFFFFF }

.category{ font: 11px Verdana,Tahoma; color: #000000; background-color: #EFEFEF }

.tableborder{ background: #4D76B3; border: 0px solid #4D76B3 }

.singleborder{ font-size: 0px; line-height: 0px; padding: 0px; background-color: #F3F6FA }

.smalltxt{ font: 11px Verdana,Tahoma }

.outertxt{ font: 12px Verdana,Tahoma; color: #000000 }

.outertxt a{ color: #000000 }

.bold{ font-weight: bold }

.altbg1{ background: #F3F6FA }

.altbg2{ background: #FFFFFF }

-->

</style>

</style>

</head>

<body leftmargin="0" rightmargin="0" topmargin="0"

onkeydown="if(event.keyCode==27) return false;">

<div id="popLayer" style="position: absolute; z-index: 1000;"

class="cPopText">

</div>

<table style="table-layout: fixed;" align="center" border="0"

cellpadding="0" cellspacing="0" width="97%">

<tbody>

<tr>

 资料管理» 上传资料

</td>

</td>

</tr>

</tbody>

</table>

<br>

<table align="center" border="0" cellpadding="0" cellspacing="0"

width="97%">

<tbody>

<tr>

</tr>

</tbody>

</table>

<table class="tableborder" align="center" cellpadding="4"

cellspacing="1" width="97%">

<tbody>

&nbs