content: package com.itheima.reggie.controller;
  
  import com.itheima.reggie.common.R;
  import lombok.extern.slf4j.Slf4j;
  import org.springframework.beans.factory.annotation.Value;
  import org.springframework.web.bind.annotation.*;
  import org.springframework.web.multipart.MultipartFile;
  
  import javax.servlet.ServletOutputStream;
  import javax.servlet.http.HttpServletResponse;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.util.UUID;
  
  /**
   * 文件上传和下载
   */
  @RestController
  @RequestMapping("/common")
  @Slf4j
  public class CommonController {
  
      @Value("${reggie.path}")
      private String basePath;
  
      /**
       * 文件上传
       * @param file
       * @return
       */
      @PostMapping("/upload")
      public R<String> upload(MultipartFile file){
          //file是一个临时文件，需要转存到指定位置，否则本次请求完成后临时文件会删除
          log.info(file.toString());
  
          //原始文件名
          String originalFilename = file.getOriginalFilename();//abc.jpg
          String suffix = originalFilename.substring(originalFilename.lastIndexOf("."));
  
          //使用UUID重新生成文件名，防止文件名称重复造成文件覆盖
          String fileName = UUID.randomUUID().toString() + suffix;//dfsdfdfd.jpg
  
          //创建一个目录对象
          File dir = new File(basePath);
          //判断当前目录是否存在
          if(!dir.exists()){
              //目录不存在，需要创建
              dir.mkdirs();
          }
  
          try {
              //将临时文件转存到指定位置
              file.transferTo(new File(basePath + fileName));
          } catch (IOException e) {
              e.printStackTrace();
          }
          return R.success(fileName);
      }
  
      /**
       * 文件下载
       * @param name
       * @param response
       */
      @GetMapping("/download")
      public void download(String name, HttpServletResponse response){
  
          try {
              //输入流，通过输入流读取文件内容
              FileInputStream fileInputStream = new FileInputStream(new File(basePath + name));
  
              //输出流，通过输出流将文件写回浏览器
              ServletOutputStream outputStream = response.getOutputStream();
  
              response.setContentType("image/jpeg");
  
              int len = 0;
              byte[] bytes = new byte[1024];
              while ((len = fileInputStream.read(bytes)) != -1){
                  outputStream.write(bytes,0,len);
                  outputStream.flush();
              }
  
              //关闭资源
              outputStream.close();
              fileInputStream.close();
          } catch (Exception e) {
              e.printStackTrace();
          }
  
      }
  }
  