1.上传组件
①Apache的Commons FileUpload
②JavaZoom的UploadBean
③JspSmartUpload
2.下载Commons的FileUpload组件
地址:http://commons.apache.org/fileupload/
同时还要下载Commons的IO组件
地址:http://commons.apache.org/io/
3.使用实例
步骤一：创建文件上传的页面：fileUpload.jsp
注意表单的 enctype 属性，这个设置很重要，详情请见：http://www.cnblogs.com/yinger/archive/2011/09/11/2173689.html
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>文件上传</title> </head> <body> <form action="<%=request.getContextPath() %>/servlet/FileUploadServlet" method="post" enctype="multipart/form-data" > 上传人名:<input type="text" name="name" /><br/> 上传文件:<input type="file" name="file" /><br/> <input type="submit" name="submit" value="提交" /> </form> </body> </html>
步骤二：创建处理文件上传的servlet：fileUploadServlet
package com.yinger.servlet; import java.io.File; import java.io.IOException; import java.util.Iterator; import java.util.List; 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.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; public class FileUploadServlet extends HttpServlet { private ServletContext sc; private String savePath; private static final long serialVersionUID = 151650843430214502L; public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("UTF-8"); DiskFileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload servletFileUpload = new ServletFileUpload(factory);//通过工厂生成一个处理文件上传的servlet对象 try { List items = servletFileUpload.parseRequest(request);//解析request Iterator iterator = items.iterator(); while (iterator.hasNext()) { FileItem item = (FileItem) iterator.next(); if(item.isFormField()){//表单的参数字段 System.out.println("表单的参数名称："+item.getFieldName()+",表单的参数值："+item.getString("UTF-8")); }else { if(item.getName()!=null && !item.getName().equals("")){//一个上传的文件 System.out.println("文件的名称："+item.getName()); System.out.println("文件的大小："+item.getSize()); System.out.println("文件的类型："+item.getContentType()); File tempFile = new File(item.getName());//getName得到的文件名称包含了它在客户端的路径 File file = new File(sc.getRealPath("/")+savePath,tempFile.getName()); item.write(file);//将上传的文件写入到file中 request.setAttribute("message", "上传文件成功！"); }else{ request.setAttribute("message", "没有选择上传文件！"); } } } } catch (Exception e) { e.printStackTrace(); request.setAttribute("message", "上传文件失败！"); } request.getRequestDispatcher("/fileUploadResult.jsp").forward(request, response);//转向，输出结果 } @Override public void init(ServletConfig config) throws ServletException { savePath = config.getInitParameter("savePath"); sc = config.getServletContext(); } }
步骤三：修改web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web=http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5"> <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.yinger.servlet.FileUploadServlet</servlet-class> <init-param> <!-- Servlet的初始化参数，配置上传文件的保存路径，这里是当前应用的uplods目录下 --> <param-name>savePath</param-name> <param-value>uploads</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>FileUploadServlet</servlet-name> <url-pattern>/servlet/FileUploadServlet</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
同时在项目的根目录下创建文件夹 uploads （可以就在WebRoot中创建）
步骤四：创建显示上传结果的页面：fileUploadResult.jsp
<%@ page language="java" pageEncoding="UTF-8"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>文件上传</title> </head> <body> <p> ${requestScope['message'] }<br/> </p> </body> </html>