Servlet上传文件

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Servlet上传文件

1、准备工作

（1）利用FileUpload组件上传文件，需要到apache上下载commons-fileupload-1.3.1.jar

下载地址：http://commons.apache.org/fileupload/

（2）由于文件上传还得有IO流传输，需要到apache上下载commons-io-2.4.jar

下载地址：http://commons.apache.org/io/

2、正式开发

（1）新建文件上传界面

file.jsp：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%  String path = request.getContextPath();  String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";  %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">         <title>上传文件前</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">  </head>    <body>    <form action="FileUploadServlet" method="post" enctype="multipart/form-data">        <table>           <tr>             <td>                <label for="username">用户名：</label>            <input type="text" name="username"/>             </td>           </tr>           <tr>             <td>               <label for="password">密  码：</label>              <input type="password" name="password"/>             </td>           </tr>           <tr>             <td>                                      <input type="file" name="fileOne" id="fileOne"/>             </td>           </tr>           <tr>             <td>                                      <input type="file" name="fileTwo" id="fileTwo"/>             </td>           </tr>           <tr>              <td>                                        <input type="submit" name="submit" id="submit" value="提交"/>                                     <input type="reset" name="reset" id="reset" value="重置"/>              </td>           </tr>        </table>    </form>  </body></html>

（2）新建文件上传成功界面

result.jsp：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%  String path = request.getContextPath();  String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";  %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">     <title>上传文件成功</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">  </head>    <body>         用户名:<%= request.getAttribute("username") %><br/>  密  码:<%= request.getAttribute("password") %><br/>  文件一:<%= request.getAttribute("fileOne") %><br/>  文件二:<%= request.getAttribute("fileTwo") %><br/>    </body></html>

（3）新建servlet进行文件上传处理

FileUploadServlet.java：

package com.you.file.servlet;import java.io.File;import java.io.IOException;import java.util.List;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.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;public class FileUploadServlet extends HttpServlet {/** * @Fields  serialVersionUID: */private static final long serialVersionUID = -3788743064732005240L;/** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to post. *  * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {/** * 设置编码格式 */request.setCharacterEncoding("UTF-8");/** * 创建一个工厂类 */DiskFileItemFactory factory = new DiskFileItemFactory();ServletContext context = getServletContext();  String path = context.getRealPath("/file");/** * 设置上传文件放在磁盘上的临时目录 */factory.setRepository(new File(path));/** * 设置上传文件大小 */factory.setSizeThreshold(1024*1024);//上传对象ServletFileUpload fileuplod = new ServletFileUpload(factory);try {/** * 解析各个表单域 */List<FileItem> list = fileuplod.parseRequest(request);for(FileItem item : list){/** * 判断是简单域 (item.isFormField()==true) */if(item.isFormField()){//获得简单域的名字String fieldName = item.getFieldName();//获得简单域的值String fieldValue = item.getString("UTF-8");request.setAttribute(fieldName, fieldValue);}else//判断是文件域 (item.isFormField()==false){//获得文件域的名字String fieldName = item.getFieldName();//获得文件域的值，带路径，即是路径+文件名String value = item.getName();//取的文件域的值的名字，不带路径int temp = value.lastIndexOf("\\");String fieldValue = value.substring(temp+1);//获得是file文件的内容request.setAttribute(fieldName, fieldValue);//写入item.write(new File(path,fieldValue));}}} catch (Exception e) {//e.printStackTrace();}/** * 跳转到上传成功界面 */request.getRequestDispatcher("result.jsp").forward(request, response);}/** * Initialization of the servlet. <br> * init方法 * @throws ServletException if an error occurs */public void init() throws ServletException {}/** * destroy方法 * Destruction of the servlet. <br> */public void destroy() {super.destroy(); }/** * The doGet method of the servlet. <br> * * This method is called when a form has its tag value method equals to get. * doGet方法 * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {this.doPost(request, response);}}

（3）配置web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app version="3.0" 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_3_0.xsd">  <display-name></display-name>  <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.you.file.servlet.FileUploadServlet</servlet-class>     </servlet>  <servlet-mapping>    <servlet-name>FileUploadServlet</servlet-name>    <url-pattern>/FileUploadServlet</url-pattern>  </servlet-mapping>    <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list></web-app>

3、过程演示

（1）初始化时

（2）输入用户名、密码，上传文件

（3）还未上传，项目中的file文件夹

（4）上传成功后，页面显示

（5）上传成功后，file文件夹

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