springmvc为文件上传提供了直接的会吃，这种支持是用即插即用的MutipartResolver实现的。springmvc使用Apache Commons FileUpload技术实现了一个MutipartResolver的实现类，CommonMultipartResolver。因此，SpringMVC的文件上传还需要依赖Apache Common FileUpload的组件
依赖的jar包
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>4.2.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.2.5.RELEASE</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-mapper-asl</artifactId>
<version>1.9.13</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.47</version>
</dependency>
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.3</version>
</dependency>
实例代码
uploadForm.jsp
<%@ 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>文件上传</title>
</head>
<body>
<h2>文件上传</h2>
<form action="upload" enctype="multipart/form-data" method="post">
<table>
<tr>
<td>文件描述:</td>
<td><input type="text" name="description"></td>
</tr>
<tr>
<td>请选择文件:</td>
<td><input type="file" name="file"></td>
</tr>
<tr>
<td><input type="submit" value="上传"></td>
</tr>
</table>
</form>
</body>
</html>
负责上传文件的表单的编码类型必须是“Multipart/form-data”
FileUploadController.java
package com.rookie.bigdata.controller;
import com.rookie.bigdata.domain.User;
import org.apache.commons.io.FileUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.http.HttpServletRequest;
import java.io.File;
/**
* Created by dell on 2019/6/16.
*/
@Controller
public class FileUploadController {
@RequestMapping(value = "/{formName}")
public String loginForm(@PathVariable String formName) {
//动态条状页面
return formName;
}
// 上传文件会自动绑定到MultipartFile中
@RequestMapping(value="/upload",method= RequestMethod.POST)
public String upload(HttpServletRequest request,
@RequestParam("description") String description,
@RequestParam("file") MultipartFile file) throws Exception {
System.out.println("执行了该方法" + description);
//判断文件是否为空
if (!file.isEmpty()) {
//获取文件的路径
String path = request.getServletContext().getRealPath("content");
//获取上传文件名
String filename = file.getOriginalFilename();
File filePath = new File(path, filename);
//判断路径是否存在，不存在就创建一个
if (!filePath.getParentFile().exists()) {
filePath.getParentFile().mkdirs();
}
file.transferTo(new File(path + File.separator + filename));
return "success";
} else {
return "error";
}
}
@RequestMapping(value="/register")
public String register(HttpServletRequest request,
@ModelAttribute User user,
Model model)throws Exception{
System.out.println(user.getUsername());
// 如果文件不为空，写入上传路径
if(!user.getImage().isEmpty()){
// 上传文件路径
String path = request.getServletContext().getRealPath(
"/content/");
// 上传文件名
String filename = user.getImage().getOriginalFilename();
File filepath = new File(path,filename);
// 判断路径是否存在，如果不存在就创建一个
if (!filepath.getParentFile().exists()) {
filepath.getParentFile().mkdirs();
}
// 将上传文件保存到一个目标文件当中
user.getImage().transferTo(new File(path+File.separator+ filename));
// 将用户添加到model
model.addAttribute("user", user);
return "userInfo";
}else{
return "error";
}
}
@RequestMapping(value="/download")
public ResponseEntity<byte[]> download(HttpServletRequest request,
@RequestParam("filename") String filename,
Model model)throws Exception{
// 下载文件路径
String path = request.getServletContext().getRealPath(
"/content/");
File file = new File(path+File.separator+ filename);
HttpHeaders headers = new HttpHeaders();
// 下载显示的文件名，解决中文名称乱码问题
String downloadFielName = new String(filename.getBytes("UTF-8"),"iso-8859-1");
// 通知浏览器以attachment（下载方式）打开图片
headers.setContentDispositionFormData("attachment", downloadFielName);
// application/octet-stream ： 二进制流数据（最常见的文件下载）。
headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
// 201 HttpStatus.CREATED
return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file),
headers, HttpStatus.CREATED);
}
}
springmvc会将上传的文件绑定到MultipartFile对象中，MultipartFile提供了获取上传文件内容，文件名等方法，通过transferTo()方法将文件存储到磁盘中
springmvc-config.xml文件
<?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:p="http://www.springframework.org/schema/p"
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-4.2.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-4.2.xsd">
<context:component-scan base-package="com.rookie.bigdata.controller"/>
<!-- 视图解析器 -->
<bean id="viewResolver"
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<!-- 前缀 -->
<property name="prefix">
<value>/WEB-INF/content/</value>
</property>
<!-- 后缀 -->
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
<bean id="multipartResolver"
class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!-- 上传文件大小上限，单位为字节（10MB） -->
<property name="maxUploadSize">
<value>10485760</value>
</property>
<!-- 请求的编码格式，必须和jSP的pageEncoding属性一致，以便正确读取表单的内容，默认为ISO-8859-1 -->
<property name="defaultEncoding">
<value>UTF-8</value>
</property>
</bean>
</beans>
用户点击进行文件上传就可以了
2、使用对象接受文件
registerForm.jsp
<%@ 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>用户注册</title>
</head>
<body>
<h2>用户注册</h2>
<form action="register" enctype="multipart/form-data" method="post">
<table>
<tr>
<td>用户名:</td>
<td><input type="text" name="username"></td>
</tr>
<tr>
<td>请上传头像:</td>
<td><input type="file" name="image"></td>
</tr>
<tr>
<td><input type="submit" value="注册"></td>
</tr>
</table>
</form>
</body>
</html>
User.java
public class User implements Serializable {
private String username;
private MultipartFile image;
输入用户名并选择上传文件头像，点击注册按钮上传用户头像进入到下载页面
<%@ 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>文件下载</title>
</head>
<body>
<h3>文件下载</h3>
<a href="download?filename=${requestScope.user.image.originalFilename}">
${requestScope.user.image.originalFilename }
</a>
</body>
</html>
进入到下载页面点击下载即可