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="https://cdn.jxasp.com:9143/image/2.5" 
	xmlns="http://java.sun.com/xml/ns/javaee" 
	xmlns:xsi="http://www.w3.orghttps://cdn.jxasp.com:9143/image/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.orghttps://cdn.jxasp.com:9143/image/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.xsd
						http://www.springframework.org/schema/mvc
						http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd
						http://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="https://cdn.jxasp.com:9143/image/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//