一、配置文件

web.xml

<?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>
public User() {}
public User(String username, String nickname, String password, String email) {
this.username = username;
this.nickname = nickname;
this.password = password;
this.email = email;
}
}

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;


@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";
}
}

三、前端代码

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>

 作者：scau_one

原文链接：https://www.cnblogs.com/scau666/p/10492267.html