JSP的文件上传方法

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环境准备

– 在项目中引入commons-fileupload-1.2.2.jar和commons-io-2.4.jar文件

设置表单的enctype属性

        <form action="UploadServlet" method="post" enctype="multipart/form-data">

注意：上传文件时form标签的method属性必须取值为“post”，不能取值为“get”

编写上传文件处理页的实现步骤

//创建FileItemFactory对象//创建ServletFileUpload对象//解析form表单中所有文件if (普通表单字段){      //获取表单字段的name属性值    if (此属性是“user”)){ //输出XXX上传了文件    }}else{   //文件表单字段    //获取上传文件的名字    if (名字不为空) {    //保存此文件并输出保存成功    }}

实例

1. index.jsp

<body>  <form action="UploadServlet" method="post"enctype="multipart/form-data">用户名 <input type="text" name="username" /> <br> 上传文件<inputtype="file" name="file" /> <br> <input type="submit" value="提交" /></form></body>

2. UploadServlet

package com.servlet;import java.io.File;import java.io.IOException;import java.io.PrintWriter;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.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;public class UploadServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {//实例化一个硬盘文件工厂，用来配置上传组件ServletFileUploadDiskFileItemFactory factory = new DiskFileItemFactory();//使用工厂对象实例化上传组件ServletFileUploadServletFileUpload upload = new ServletFileUpload(factory);try {//使用集合获取表单的所有数据List<FileItem> items = upload.parseRequest(request);for (int i =0;i<items.size();i++){FileItem item = items.get(i);//普通表单域if(item.isFormField()){//获得表单元素的nameString name = item.getFieldName();if(name.equals("username")){//获得表单元素的值String value =item.getString("utf-8");System.out.println("name:"+name+"\tvalue:"+value);}}else{//上传文件//获得文件在Apache的保存路径String filepath = getServletContext().getRealPath("/");//根目录String filename = item.getName();//文件名称，上传文件的真实名称String path = filepath +"upload\\"+filename;//创建一个文件对象File file = new File(path);//生成一个文件(复制)item.write(file);}}} catch (FileUploadException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}response.setContentType("text/html;charset=utf-8");PrintWriter out = response.getWriter();out.print("文件上传成功");out.flush();out.close();}}

测试

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