在很多的jsp 项目中，我们要上传附件，如很多的BBS也有这样的功能，邮件也一样，相信大家已非常熟悉了，这里就介绍他是怎么实现的；
这里我们选择第三方组件，你可以选择：commons-fileupload 或jspSmartUpload
这里我们选择apache的commons-fileupload;
这个组件的包你可以在：http://jakarta.apache.org/site/downloads/下载
可以在左边的导航中找到Commons然后在里面找到commons-fileupload
在用这个包的同时我们还用到了apache的io包，它同样在Commons里可以找到；
下面是书上的一个实例代码：
upload.jsp
<%@ page language="java" contentType="text/html;charset=GBK" pageEncoding="GBK"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=GBK"><title>Insert title here</title></head><body> common file upload 上传实例<br> <form method="post" action="FileUpload" ENCTYPE="multipart/form-data"> 文件:<input type="file" name="file"/> <input type="submit" value="上传" name="submit"> </form></body></html>
下面是一个处理的servlet
FileUpload.java
package servlet;import java.io.File;import java.io.IOException;import java.io.PrintWriter;import java.util.Iterator;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.FileItemFactory;import org.apache.commons.fileupload.disk.DiskFileItemFactory;import org.apache.commons.fileupload.servlet.ServletFileUpload;public class FileUpload extends HttpServlet { private static final long serialVersionUID = 1L; public FileUpload() { super(); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { boolean isMultipart=ServletFileUpload.isMultipartContent(request); if(isMultipart){ FileItemFactory factory=new DiskFileItemFactory(); ServletFileUpload upload=new ServletFileUpload(factory); Iterator items; try{ items=upload.parseRequest(request).iterator(); while(items.hasNext()){ FileItem item=(FileItem)items.next(); if(!item.isFormField()){ String name=item.getName(); String fileName=name.substring(name.lastIndexOf('\\')+1, name.length()); String path=request.getRealPath("file")+ File.separatorChar+fileName; File uploadFile=new File(path); item.write(uploadFile); response.setContentType("text/html"); response.setCharacterEncoding("gb2312"); PrintWriter out=response.getWriter(); out.print("<font size='12'>上传文件为"+name+"<br>"); out.print("保存地址为"+path+"<br>"); } } }catch(Exception e){ e.printStackTrace(); } } }}
相关资源：文件上传组件
