SpringMVC中的文件上传

完整版见 https://jadyer.github.io/2012/05/17/springmvc-annotation/

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

首先是web.xml

  
		upload
		org.springframework.web.servlet.DispatcherServlet
		1
	
	
		upload
		/
	

	
		SpringCharacterEncodingFilter
		org.springframework.web.filter.CharacterEncodingFilter
		
			encoding
			UTF-8
		
	
	
		SpringCharacterEncodingFilter
		/*
	
	
	
		/WEB-INF/jsp/user/add.jsp
	

接下来是SpringMVC的配置文件upload-servlet.xml

	
	
	
		
		
	
	
	
	
		
		
		
	
	
	
	
	
		
			
				
				error_fileupload
			
		
	

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

<%@ page language="java" pageEncoding="UTF-8"%>

	username: 

	nickname: 

	password: 

	yourmail: 

	yourfile: 

	yourfile: 

	yourfile: 

	

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"%>

	${user.value.username}----${user.value.nickname}----${user.value.password}----${user.value.email}
	    查看
	    编辑
	    删除
	




继续添加用户

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"%>
文件过大，请重新选择

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
 * @author 宏宇
 * @create May 12, 2012 1:26:21 AM
 */
@Controller
@RequestMapping("/user")
public class UserController {
	private final static Map users = new HashMap();
	
	//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", "[email protected]"));
		users.put("李寻欢", new User("李寻欢", "李探花", "08866659", "[email protected]"));
		users.put("拓拔野", new User("拓拔野", "搜神记", "05577759", "[email protected]"));
		users.put("孙悟空", new User("孙悟空", "美猴王", "03311159", "[email protected]"));
	}
	
	@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";
	}
}

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