spring boot 实现文件上传和下载，以及多文件上传
（1）、创建maven项目
（2）、在templates中创建html文件
html>
<html lang="en">
<head>
<meta name="keywords" content="keyword1,keyword2,keyword3">meta>
<meta name="description" content="this is my page">meta>
<meta name="content-type" content="text/html; charset=UTF-8">meta>
<title>fileUploadtitle>
head>
<body>
<form action="/upload" enctype="multipart/form-data" method="post">
姓名：<input type="text" name="username"/>
<br/>
头像：<input type="file" name="filename"/>
<input type="submit" value="上传"/>
form>
<hr/>
<a href="/download">文件下载a>
<br/>
<form action="/batch/upload" method="post" enctype="multipart/form-data">
文件1：<input type="file" name="file"/><br/>
文件2：<input type="file" name="file"/><br/>
<input type="submit" value="多文件上传"/>
form>
body>
html>
（3）、在webapp下创建存储临时文件夹file
（4）、pom.xml代码：
xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0modelVersion>
<groupId>com.example.filegroupId>
<artifactId>fileuploadartifactId>
<version>0.0.1-SNAPSHOTversion>
<packaging>jarpackaging>
<name>fileuploadname>
<description>Demo project for Spring Bootdescription>
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>1.5.10.RELEASEversion>
<relativePath/>
parent>
<properties>
<project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8project.reporting.outputEncoding>
<java.version>1.8java.version>
properties>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.mybatis.spring.bootgroupId>
<artifactId>mybatis-spring-boot-starterartifactId>
<version>1.3.1version>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
<dependency>
<groupId>commons-logginggroupId>
<artifactId>commons-loggingartifactId>
<version>1.2version>
dependency>
<dependency>
<groupId>org.apache.maven.pluginsgroupId>
<artifactId>maven-war-pluginartifactId>
<version>3.2.0version>
dependency>
<dependency>
<groupId>org.slf4jgroupId>
<artifactId>slf4j-apiartifactId>
<version>1.7.5version>
dependency>
<dependency>
<groupId>org.slf4jgroupId>
<artifactId>slf4j-log4j12artifactId>
<version>1.7.12version>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starterartifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-loggingartifactId>
exclusion>
exclusions>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-log4jartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-thymeleafartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-devtoolsartifactId>
<optional>trueoptional>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-jdbcartifactId>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<scope>runtimescope>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-data-jpaartifactId>
dependency>
<dependency>
<groupId>org.mybatis.spring.bootgroupId>
<artifactId>mybatis-spring-boot-starterartifactId>
<version>1.3.1version>
dependency>
<dependency>
<groupId>com.alibabagroupId>
<artifactId>druidartifactId>
<version>1.0.26version>
dependency>
<dependency>
<groupId>org.apache.tomcat.embedgroupId>
<artifactId>tomcat-embed-jasperartifactId>
<scope>providedscope>
dependency>
<dependency>
<groupId>javax.servletgroupId>
<artifactId>jstlartifactId>
<version>1.2version>
dependency>
dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
plugin>
plugins>
build>
project>
（5）、controller代码：
package com.example.file.fileupload.controller; import com.example.file.fileupload.entity.Users; import com.example.file.fileupload.service.UsersService; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.*; import org.springframework.web.multipart.MultipartFile; import org.springframework.web.multipart.MultipartHttpServletRequest; import javax.annotation.Resource; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.*; import java.util.List; @Controller public class FileController { //导入service层 @Resource private UsersService usersService; @RequestMapping(value = "/goto",method = RequestMethod.GET) public String goUpload(){ return "index"; } //日志信息 private static final Logger logger = LoggerFactory.getLogger(FileController.class); //文件上传相关代码 @RequestMapping(value = "/upload",method = RequestMethod.POST) @ResponseBody public String upload(@RequestParam("filename") MultipartFile file,@RequestParam("username") String username, HttpServletRequest request){ //判断文件是否为空 if(file.isEmpty()){ return "文件为空"; } //获取文件名 String fileName = file.getOriginalFilename(); logger.info("上传文件名为："+fileName); //获取文件后缀名 String suffixName = fileName.substring(fileName.lastIndexOf(".")); logger.info("文件的后缀名为："+suffixName); //上传后存放路径,webapp/file String filePath = request.getSession().getServletContext().getRealPath("file/"); //重命名文件名 String fileNewName = System.currentTimeMillis()+suffixName; //创建文件目录 File src = new File(filePath+fileNewName); //检查文件目录是否存在 if(!src.getParentFile().exists()){ src.getParentFile().mkdirs(); } //上传文件 try{ file.transferTo(src); //上传文件保存到数据库 Users u = new Users(); logger.info("username="+username); u.setUserName(username); u.setPhoto("file/"+fileNewName); this.usersService.insertUsers(u); return "上传成功！"; }catch (Exception e){ e.printStackTrace(); } return "上传失败!"; } //文件下载代码 @RequestMapping(value = "/download",method = RequestMethod.GET) public String downFile(HttpServletRequest request, HttpServletResponse response){ String fileName = "123.jpg"; if(fileName != null){ //获取当前路径下的文件 String realPath = request.getServletContext().getRealPath("/file/")+fileName; File file = new File(realPath); //判断文件的对否存在 if(file.exists()){ //设置强制下载，不打开 response.setContentType("application/x-msdownload"); //设置文件名 response.addHeader("Content-Disposition","attachment;fileName="+fileName); byte[] bytes = new byte[1024]; FileInputStream fis = null; BufferedInputStream bis = null; try{ fis = new FileInputStream(file); bis = new BufferedInputStream(fis); OutputStream os = response.getOutputStream(); int b = bis.read(bytes); while(b != -1){ os.write(bytes,0,b); b = bis.read(bytes); } os.close(); return "下载成功！"; }catch (Exception e){ e.printStackTrace(); }finally { if (bis != null) { try { bis.close(); } catch (IOException e) { e.printStackTrace(); } } if (fis != null) { try { fis.close(); } catch (IOException e) { e.printStackTrace(); } } } } } return "下载失败！"; } //多文件上传 @RequestMapping(value = "/batch/upload",method = RequestMethod.POST) @ResponseBody public String MoreFileUpload(HttpServletRequest request){ //获取上传文件list Listfiles = ((MultipartHttpServletRequest) request).getFiles("file"); MultipartFile file = null; BufferedOutputStream bos = null; //遍历文件 for(int i = 0; i < files.size();i++){ file = files.get(i); //判断文件的是否存在 if(!file.isEmpty()){ try{ //获取文件名 String fileName = file.getOriginalFilename(); logger.info("上传文件名为："+fileName); //获取文件后缀名 String suffixName = fileName.substring(fileName.lastIndexOf(".")); logger.info("文件的后缀名为："+suffixName); //上传后存放路径,webapp/file String filePath = request.getSession().getServletContext().getRealPath("file/"); //重命名文件名 String fileNewName = System.currentTimeMillis()+suffixName; //System.out.println("当前文件名："+fileName); //创建文件目录 File src = new File(filePath+fileNewName); //检查文件目录是否存在 byte[] bytes = file.getBytes(); bos = new BufferedOutputStream(new FileOutputStream(src)); bos.write(bytes); bos.close(); }catch (Exception e){ bos = null; return "上传失败原因是："+e.getMessage(); } } return "上传失败！"; } return "上传成功！"; } }
（6）、运行http://localhost:8080/**即可