檔案上傳/下載後臺程式碼

import cn.hutool.core.io.FileUtil;
import cn.hutool.core.util.StrUtil;
import com.example.common.Result;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.List;

/**

• 檔案上傳介面
  */
  @RestController
  @RequestMapping("/files")
  public class FileController {

  //檔案上傳路徑
  private static final String filePath = System.getProperty("user.dir") + "/file/";

  /**

  • 檔案上傳
    */
    @PostMapping("/upload")
    public Result upload(MultipartFile file){
    synchronized (FileController.class){
    String flag =System.currentTimeMillis()+"";
    String fileName = file.getOriginalFilename();
    try{
    if(!FileUtil.isDirectory(filePath)){
    FileUtil.mkdir(filePath);
    }
    //檔案儲存格式：時間戳-檔名
    FileUtil.writeBytes(file.getBytes(),filePath + flag + "-" + fileName);
    System.out.println(fileName +"--上傳成功");
    Thread.sleep(1L);
    } catch (IOException | InterruptedException e) {
    System.out.println(fileName + "--檔案上傳失敗");
    }
    return Result.success(flag);
    }
    }

  @GetMapping("/{flag}")
  public void avatarPath(@PathVariable String flag, HttpServletResponse response){
  if (!FileUtil.isDirectory(filePath)){
  FileUtil.mkdir(filePath);
  }
  OutputStream os;
  List fileNames = FileUtil.listFileNames(filePath);
  String avatar = fileNames.stream().filter(name -> name.contains(flag)).findAny().orElse("");
  try {
  if (StrUtil.isNotEmpty(avatar)){
  response.addHeader("Content-Disposition","attachment;filename"+ URLEncoder.encode(avatar,"UTF-8"));
  response.setContentType("application/octet-stream");
  byte[] bytes = FileUtil.readBytes(filePath + avatar);
  os = response.getOutputStream();
  os.write(bytes);
  os.flush();
  os.close();
  }
  } catch (Exception e) {
  System.out.println("檔案下載失敗");
  }
  }
  }