springmvc 多文件/文件夹上传 下载

注入依赖

   <properties>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <maven.compiler.source>1.7</maven.compiler.source>
     <maven.compiler.target>1.7</maven.compiler.target>
       <spring.version>4.3.24.RELEASE</spring.version>
   </properties>

     <dependencies>
         <!-- Spring -->
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-core</artifactId>
             <version>${spring.version}</version>
         </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-context</artifactId>
             <version>${spring.version}</version>
         </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-web</artifactId>
             <version>${spring.version}</version>
         </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-context-support</artifactId>
             <version>${spring.version}</version>
         </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-webmvc</artifactId>
             <version>${spring.version}</version>
         </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-test</artifactId>
             <version>${spring.version}</version>
         </dependency>
         <!-- JSTL（JSP Standard Tag Library ，JSP标准标签库)是一个不断完善的开放源代码的JSP标签 -->
         <dependency>
             <groupId>javax.servlet</groupId>
             <artifactId>jstl</artifactId>
             <version>1.2</version>
         </dependency>
         <!-- Servlet包含的类以及方法 -->
         <dependency>
             <groupId>javax.servlet</groupId>
             <artifactId>javax.servlet-api</artifactId>
             <version>3.0.1</version>
         </dependency>
         <dependency>
             <groupId>org.hibernate</groupId>
             <artifactId>hibernate-validator</artifactId>
             <version>5.2.4.Final</version>
         </dependency>

         <dependency>
             <groupId>com.google.code.gson</groupId>
             <artifactId>gson</artifactId>
             <version>2.8.5</version>
         </dependency>
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <version>4.11</version>
             <scope>test</scope>
         </dependency>

         <!-- jackson -->
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-core</artifactId>
             <version>2.9.3</version>
         </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-annotations</artifactId>
             <version>2.9.3</version>
         </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>
             <version>2.9.3</version>
         </dependency>

         <!--文件上传下载 -->
         <dependency>
             <groupId>commons-io</groupId>
             <artifactId>commons-io</artifactId>
             <version>2.4</version>
         </dependency>
         <dependency>
             <groupId>commons-fileupload</groupId>
             <artifactId>commons-fileupload</artifactId>
             <version>1.3</version>
         </dependency>
   </dependencies>

xml配置

 <!-- 多部分文件上传 M kb byte-->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxUploadSize" value="104857600"/>
        <property name="defaultEncoding" value="UTF-8"></property>
    </bean>

核心源码

 package com.etc.controller;

 import org.apache.commons.io.IOUtils;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.multipart.MultipartFile;

 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;

 @Controller
 public class FileController {
     @RequestMapping("/upload.do")
     public String upload(@RequestParam MultipartFile img, HttpServletRequest request) throws IOException {
         String dir = request.getServletContext().getRealPath("/upload");
         img.transferTo(new File(dir + "/" + img.getOriginalFilename()));
         return "success";
     }

     @RequestMapping("/uploads.do")
     public String uploads(@RequestParam MultipartFile[] img, HttpServletRequest request) throws IOException {
         String dir = request.getServletContext().getRealPath("/upload");
         for (MultipartFile i : img) {
             i.transferTo(new File(dir + "/" + i.getOriginalFilename()));
         }
         return "success";
     }

     @RequestMapping("/download.do")
     public String down(String filename, HttpServletResponse response) throws IOException {
         String str="D:\\Documents\\Pictures\\";
         response.setContentType("application/octet-stream");//让浏览器弹 出下载框
         response.addHeader("Content-Disposition", "attachment;filename=" + filename);// 指定下载的文件的名字
         response.addHeader("Content-Length", "" + new File(str + filename).length());//说明一下下载的文件的大小,
         IOUtils.copy(new FileInputStream(str+filename),response.getOutputStream());
         return null;
     }
 }