SpringMVC中的文件上传

这是用的是SpringMVC-3.1.1、commons-fileupload-1.2.2和io-2.0.1

web.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 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_2_5.xsd"><servlet><servlet-name>upload</servlet-name><servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class><load-on-startup>1</load-on-startup></servlet><servlet-mapping><servlet-name>upload</servlet-name><url-pattern>/</url-pattern></servlet-mapping><filter><filter-name>SpringCharacterEncodingFilter</filter-name><filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class><init-param><param-name>encoding</param-name><param-value>UTF-8</param-value></init-param></filter><filter-mapping><filter-name>SpringCharacterEncodingFilter</filter-name><url-pattern>/*</url-pattern></filter-mapping><welcome-file-list><welcome-file>/WEB-INF/jsp/user/add.jsp</welcome-file></welcome-file-list>
</web-app>

接下来是SpringMVC的配置文件upload-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:mvc="http://www.springframework.org/schema/mvc"xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsdhttp://www.springframework.org/schema/mvchttp://www.springframework.org/schema/mvc/spring-mvc-3.1.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd"><context:component-scan base-package="com.jadyer"/><bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"><property name="prefix" value="/WEB-INF/jsp/"/><property name="suffix" value=".jsp"/></bean><!-- SpringMVC上传文件时，需要配置MultipartResolver处理器 --><bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"><property name="defaultEncoding" value="UTF-8"/><!-- 指定所上传文件的总大小不能超过200KB。注意maxUploadSize属性的限制不是针对单个文件，而是所有文件的容量之和 --><property name="maxUploadSize" value="200000"/></bean><!-- SpringMVC在超出上传文件限制时，会抛出org.springframework.web.multipart.MaxUploadSizeExceededException --><!-- 该异常是SpringMVC在检查上传的文件信息时抛出来的，而且此时还没有进入到Controller方法中 --><bean id="exceptionResolver" class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver"><property name="exceptionMappings"><props><!-- 遇到MaxUploadSizeExceededException异常时，自动跳转到/WEB-INF/jsp/error_fileupload.jsp页面 --><prop key="org.springframework.web.multipart.MaxUploadSizeExceededException">error_fileupload</prop></props></property></bean>
</beans>

下面是用于上传的表单页面//WEB-INF//jsp//user//add.jsp

<%@ page language="java" pageEncoding="UTF-8"%>
<form action="<%=request.getContextPath()%>/user/add" method="POST" enctype="multipart/form-data">username: <input type="text" name="username"/><br/>nickname: <input type="text" name="nickname"/><br/>password: <input type="password" name="password"/><br/>yourmail: <input type="text" name="email"/><br/>yourfile: <input type="file" name="myfiles"/><br/>yourfile: <input type="file" name="myfiles"/><br/>yourfile: <input type="file" name="myfiles"/><br/><input type="submit" value="添加新用户"/>
</form>

下面是上传成功后打印用户信息的页面//WEB-INF//jsp//user//list.jsp

<%@ page language="java" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<c:forEach items="${users}" var="user">${user.value.username}----${user.value.nickname}----${user.value.password}----${user.value.email}<a href="<%=request.getContextPath()%>/user/${user.value.username}">查看</a><a href="<%=request.getContextPath()%>/user/${user.value.username}/update">编辑</a><a href="<%=request.getContextPath()%>/user/${user.value.username}/delete">删除</a><br/>
</c:forEach>
<br/>
<a href="<%=request.getContextPath()%>/user/add">继续添加用户</a>

下面是上传文件内容过大时的提示页面//WEB-INF//jsp//error_fileupload.jsp

<%@ page language="java" pageEncoding="UTF-8"%>
<h1>文件过大，请重新选择</h1>

接下来是用到的实体类User.java

package com.jadyer.model;/*** User* @author 宏宇* @create May 12, 2012 1:24:43 AM*/
public class User {private String username;private String nickname;private String password;private String email;/*==四个属性的getter()、setter()略==*/public User() {}public User(String username, String nickname, String password, String email) {this.username = username;this.nickname = nickname;this.password = password;this.email = email;}
}

最后是核心的UserController.java

package com.jadyer.controller;import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;import javax.servlet.http.HttpServletRequest;import org.apache.commons.io.FileUtils;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;import com.jadyer.model.User;/*** SpringMVC中的文件上传* @see 第一步：由于SpringMVC使用的是commons-fileupload实现，故将其组件引入项目中* @see       这里用到的是commons-fileupload-1.2.2.jar和commons-io-2.0.1.jar* @see 第二步：在####-servlet.xml中配置MultipartResolver处理器。可在此加入对上传文件的属性限制* @see 第三步：在Controller的方法中添加MultipartFile参数。该参数用于接收表单中file组件的内容* @see 第四步：编写前台表单。注意enctype="multipart/form-data"以及<input type="file" name="****"/>* @author 宏宇* @create May 12, 2012 1:26:21 AM*/
@Controller
@RequestMapping("/user")
public class UserController {private final static Map<String,User> users = new HashMap<String,User>();//模拟数据源,构造初始数据public UserController(){users.put("张起灵", new User("张起灵", "闷油瓶", "02200059", "menyouping@yeah.net"));users.put("李寻欢", new User("李寻欢", "李探花", "08866659", "lixunhuan@gulong.cn"));users.put("拓拔野", new User("拓拔野", "搜神记", "05577759", "tuobaye@manhuang.cc"));users.put("孙悟空", new User("孙悟空", "美猴王", "03311159", "sunhouzi@xiyouji.zh"));}@RequestMapping("/list")public String list(Model model){model.addAttribute("users", users);return "user/list";}@RequestMapping(value="/add", method=RequestMethod.GET)public String addUser(){return "user/add";}@RequestMapping(value="/add", method=RequestMethod.POST)public String addUser(User user, @RequestParam MultipartFile[] myfiles, HttpServletRequest request) throws IOException{//如果只是上传一个文件，则只需要MultipartFile类型接收文件即可，而且无需显式指定@RequestParam注解//如果想上传多个文件，那么这里就要用MultipartFile[]类型来接收文件，并且还要指定@RequestParam注解//并且上传多个文件时，前台表单中的所有<input type="file"/>的name都应该是myfiles，否则参数里的myfiles无法获取到所有上传的文件for(MultipartFile myfile : myfiles){if(myfile.isEmpty()){System.out.println("文件未上传");}else{System.out.println("文件长度: " + myfile.getSize());System.out.println("文件类型: " + myfile.getContentType());System.out.println("文件名称: " + myfile.getName());System.out.println("文件原名: " + myfile.getOriginalFilename());System.out.println("========================================");//如果用的是Tomcat服务器，则文件会上传到\\%TOMCAT_HOME%\\webapps\\YourWebProject\\WEB-INF\\upload\\文件夹中String realPath = request.getSession().getServletContext().getRealPath("/WEB-INF/upload");//这里不必处理IO流关闭的问题，因为FileUtils.copyInputStreamToFile()方法内部会自动把用到的IO流关掉，我是看它的源码才知道的FileUtils.copyInputStreamToFile(myfile.getInputStream(), new File(realPath, myfile.getOriginalFilename()));}}users.put(user.getUsername(), user);return "redirect:/user/list";}
}

记得建立这个目录，用于存放上传的文件，即//WEB-INF//upload//