package com.lanqiao.javaweb;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;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 {    private static final long serialVersionUID = 1L;    public void doPost(HttpServletRequest request, HttpServletResponse response)             throws ServletException, IOException {                // 1. 得到 FileItem 的集合 items        // Create a factory for disk-based file items        DiskFileItemFactory factory = new DiskFileItemFactory();        //        FileCleaningTracker fileCleaningTracker = //        FileCleanerCleanup.getFileCleaningTracker(getServletContext());//        factory.setFileCleaningTracker(fileCleaningTracker);                        // Set factory constraints，设置文件的大小        factory.setSizeThreshold(1024 * 500);                        //超过该大小，就读到临时的文件里面        File tempDirectory = new File("f:\\tempDirectory");        factory.setRepository(tempDirectory);        // Create a new file upload handler；上传该文件        ServletFileUpload upload = new ServletFileUpload(factory);                // Set overall request size constraint；设置文件总的大小        upload.setSizeMax(1024 * 1024 * 5);                // Parse the request        try {            //获取jsp文件里的请求，在集合中            List<FileItem> /* FileItem */items = upload.parseRequest(request);            // 2. 遍历 items:            for (FileItem item : items) {                // 若是一个一般的表单域, 打印信息                if (item.isFormField()) {                    String name = item.getFieldName();                    String value = item.getString();                    System.out.println(name + ": " + value);                                                                        }                // 若是文件域则把文件保存到 d:\\files 目录下.                else {                    //文件名为file                    String fieldName = item.getFieldName();                                            //上传的原始的文件名                    String fileName = item.getName();                                            //上传的文件的类型                    String contentType = item.getContentType();                                                //上传的文件的大小                    long sizeInBytes = item.getSize();                    System.out.println(fieldName);                    System.out.println(fileName);                    System.out.println(contentType);                    System.out.println(sizeInBytes);                    InputStream in = item.getInputStream();                    byte[] buffer = new byte[1024];                    int len = 0;                                                //文件上传后的 路径和文件名                    fileName = "f:\\files\\" + fileName;                    System.out.println(fileName);                    OutputStream out = new FileOutputStream(fileName);                                                while ((len = in.read(buffer)) != -1) {                        out.write(buffer, 0, len);                    }                    out.close();                    in.close();                }            }        } catch (FileUploadException e) {            e.printStackTrace();        }            }}

<?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" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">  <display-name>day-14-fileupload</display-name>
  <servlet>    <description></description>    <display-name>UploadServlet</display-name>    <servlet-name>UploadServlet</servlet-name>    <servlet-class>com.lanqiao.javaweb.UploadServlet</servlet-class>  </servlet>
  <servlet-mapping>    <servlet-name>UploadServlet</servlet-name>    <url-pattern>/uploadServlet</url-pattern>  </servlet-mapping>
</web-app>

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!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=UTF-8"><title>Insert title here</title></head><body>        <form action="uploadServlet" method="post" enctype="multipart/form-data">                &nbsp;&nbsp;File:&nbsp;&nbsp;<input type="file" name="file"/>        <br><br>        Desc:&nbsp;&nbsp;<input type="text" name="desc"/>        <br><br>        <input type="submit" value="http://www.mamicode.com/Submit"/>    </form>    </body></html>