package com.cao.dto;

 public class FileInfo {

     private String path;

     public FileInfo(String path) {

         this.path=path;

     }

     public String getPath() {

         return path;

     }

     public void setPath(String path) {

         this.path = path;

     }

 }

 package com.cao.web.controller;

 import java.io.File;

 import java.io.IOException;

 import java.util.Date;

 import org.springframework.web.bind.annotation.PostMapping;

 import org.springframework.web.bind.annotation.RequestMapping;

 import org.springframework.web.bind.annotation.RestController;

 import org.springframework.web.multipart.MultipartFile;

 import com.cao.dto.FileInfo;

 @RestController

 @RequestMapping("/file")

 public class FileController {

     @PostMapping

     public FileInfo uploadFile(MultipartFile fileKey) throws Exception {

         System.out.println("fileName: "+fileKey.getName());

         System.out.println("OriginalFilename: "+fileKey.getOriginalFilename());

         System.out.println("size: "+fileKey.getSize());

         //将要存储在controller的目录下

         String folder="E:\\workspace-sts-3.9.5.RELEASE\\it-security-demo\\src\\main\\java\\com\\cao\\web\\controller";

         File localFile=new File(folder,new Date().getTime()+".txt");

         fileKey.transferTo(localFile);

         //写入流中，这个主要用于写入其他的地方，例如服务器等，这里不写了

         //fileKey.getInputStream()

         return new FileInfo(localFile.getAbsolutePath());

     }

 }

 /**

      * 测试文件的上传

      * @throws Exception

      */

     @Test

     public void whenUploadSuccess() throws Exception {

         String result=mockMvc.perform(MockMvcRequestBuilders.fileUpload("/file")

                 .file(new MockMultipartFile("fileKey","test.txt","multipart/form-data","hello".getBytes("UTF-8"))))

                 .andExpect(MockMvcResultMatchers.status().isOk())

                 .andReturn().getResponse().getContentAsString();

         System.out.println("result="+result);

     }

           <dependency>

             <groupId>commons-io</groupId>

             <artifactId>commons-io</artifactId>

           </dependency>

 package com.cao.web.controller;

 import java.io.File;

 import java.io.FileInputStream;

 import java.io.IOException;

 import java.io.InputStream;

 import java.io.OutputStream;

 import java.util.Date;

 import javax.servlet.http.HttpServletRequest;

 import javax.servlet.http.HttpServletResponse;

 import org.apache.commons.io.IOUtils;

 import org.springframework.web.bind.annotation.GetMapping;

 import org.springframework.web.bind.annotation.PathVariable;

 import org.springframework.web.bind.annotation.PostMapping;

 import org.springframework.web.bind.annotation.RequestMapping;

 import org.springframework.web.bind.annotation.RestController;

 import org.springframework.web.multipart.MultipartFile;

 import com.cao.dto.FileInfo;

 @RestController

 @RequestMapping("/file")

 public class FileController {

     String folder="E:\\workspace-sts-3.9.5.RELEASE\\it-security-demo\\src\\main\\java\\com\\cao\\web\\controller";

     /**

      * 文件的上传控制器

      * @param fileKey

      * @return

      * @throws Exception

      */

     @PostMapping

     public FileInfo uploadFile(MultipartFile fileKey) throws Exception {

         System.out.println("fileName: "+fileKey.getName());

         System.out.println("OriginalFilename: "+fileKey.getOriginalFilename());

         System.out.println("size: "+fileKey.getSize());

         //将要存储在controller的目录下

         File localFile=new File(folder,new Date().getTime()+".txt");

         fileKey.transferTo(localFile);

         //写入流中，这个主要用于写入其他的地方，例如服务器等，这里不写了

         //fileKey.getInputStream()

         return new FileInfo(localFile.getAbsolutePath());

     }

     /**

      * 文件的下载

      */

     @GetMapping("/{id}")

     public void downFile(@PathVariable String id, HttpServletRequest request,HttpServletResponse response) {

         try(

             InputStream inputStream=new FileInputStream(new File(folder,id+".txt"));

             OutputStream outputStream=response.getOutputStream();

             )

         {

             response.setContentType("application/x-download");

             response.addHeader("Content-Disposition", "attachment;filename=test.txt");

             IOUtils.copy(inputStream, outputStream);

             outputStream.flush();

         } catch (Exception e) {

             // TODO: handle exception

         }

     }

 }