Java Web 文件上传
在我们的web开发中，很多的时候都需要把本机的一些文件上传到web服务器上面去
如：一个BBS系统，当用户使用这是系统的时候，能把本机的一些图片，文档上传到服务器
上面去。然后其他用户可以去下载这些文件，那么这样的话，我们可以自己编程实现文件的上传
但是更好的方式是使用一些已有的组件帮助我们实现这种上传功能。
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常用的上传组件：
Apache 的 Commons FileUpload
JavaZoom的UploadBean
jspSmartUpload
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FileUpload下载地址：
http://commons.apache.org/fileupload/
下载：commons-fileupload-1.2.2-bin.zip 得到：commons-fileupload-1.2.2.jar
http://commons.apache.org/io/
下载：commons-io-1.4-bin.zip 得到：commons-io-1.4.jar
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upload.jsp
代码；
<%@ page language="java" contentType="text/html; charset=UTF-8"%> <html> <head> <title>using commons Upload to upload file </title> </head> <style> * { font-family: "宋体"; font-size: 14px } </style> <body> <p align="center"> 请您选择需要上传的文件</p> <form id="form1" name="form1" method="post" action="servlet/fileServlet" enctype="multipart/form-data"> <table border="0" align="center"> <tr> <td>上传人：</td> <td> <input name="name" type="text" id="name" size="20" ></td> </tr> <tr> <td>上传文件：</td> <td><input name="file" type="file" size="20" ></td> </tr> <tr> <td></td><td> <input type="submit" name="submit" value="提交" > <input type="reset" name="reset" value="重置" > </td> </tr> </table> </form> </body> </html>
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FileUploadServlet.java
代码：
/** * */ package com.b510.example;
import java.io.File; import java.io.IOException; import java.util.*;
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;
/** * * @author XHW * * @date 2011-7-26 * */ public class FileUploadServlet extends HttpServlet {
private static final long serialVersionUID = -7744625344830285257L; private ServletContext sc; private String savePath;
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); }
public void init(ServletConfig config) { // 在web.xml中设置的一个初始化参数 savePath = config.getInitParameter("savePath"); sc = config.getServletContext(); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); DiskFileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); try { List items = upload.parseRequest(request); Iterator itr = items.iterator(); while (itr.hasNext()) { FileItem item = (FileItem) itr.next(); if (item.isFormField()) { System.out.println("表单参数名:" + item.getFieldName() + "，表单参数值:" + item.getString("UTF-8")); } else { if (item.getName() != null && !item.getName().equals("")) { System.out.println("上传文件的大小:" + item.getSize()); System.out.println("上传文件的类型:" + item.getContentType()); // item.getName()返回上传文件在客户端的完整路径名称 System.out.println("上传文件的名称:" + item.getName());
File tempFile = new File(item.getName());
／／上传文件的保存路径 File file = new File(sc.getRealPath("/") + savePath, tempFile.getName()); item.write(file); request.setAttribute("upload.message", "上传文件成功！"); }else{ request.setAttribute("upload.message", "没有选择上传文件！"); } } } }catch(FileUploadException e){ e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); request.setAttribute("upload.message", "上传文件失败！"); } request.getRequestDispatcher("/uploadResult.jsp").forward(request, response); } }
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uploadResult.jsp
代码；
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>uploadResult</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> -->
</head> <body> ${requestScope['upload.message'] } <a href="/upload/uploadFile.jsp">上传文件</a> </body> </html>
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web.xml
代码：
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <servlet> <description>This is the description of my J2EE component</description> <display-name>This is the display name of my J2EE component</display-name> <servlet-name>FileUploadServlet</servlet-name> <servlet-class>com.b510.example.FileUploadServlet</servlet-class>
＜！--设置初始化参数--＞ <init-param> <param-name>savePath</param-name> <param-value>uploads</param-value> </init-param> </servlet>
<servlet-mapping> <servlet-name>FileUploadServlet</servlet-name> <url-pattern>/servlet/fileServlet</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> <welcome-file>uploadFile.jsp</welcome-file> </welcome-file-list> </web-app>
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