springboot集成minio SDK实现文件上传下载（下）

// 文件上传
@PostMapping("/image/upload")
String upload(@RequestPart("userImage") MultipartFile userImage) throws Exception {
    fileService.putObject("image", userImage);
    return "success";
}
/**
   * 下载
   *
   * @param fileId
   * @param response
   * @throws Exception
   */
@GetMapping("/download/{fileId}")
public void download(@PathVariable("fileId") String fileId, HttpServletResponse response) throws Exception {
    fileService.getObject(fileId, response);
}
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import com.example.awesomespring.bo.FileUploadResult;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.http.HttpServletResponse;
/**
 * @author zouwei
 * @className FileService
 * @date: 2022/8/4 下午3:45
 * @description:
 */
public interface FileService {
  // 上传功能，把文件提交到minio服务，并把提交结果持久化
  FileUploadResult putObject(String dirs, MultipartFile file) throws Exception;
  // 下载功能，把minio服务中的文件下载并写入响应
  void getObject(String fileId, HttpServletResponse response) throws Exception;
}
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import lombok.Data;
/**
* @author zouwei
* @className FileUploadResult
* @date: 2022/8/4 下午11:59
* @description:
*/
@Data
public class FileUploadResult {
    // 文件桶名称
    private String bucketName;
    // 文件存储的路径
    private String filePath;
    // 文件名称
    private String filename;
    // 文件上传类型
    private String contentType;
    // 文件大小
    private int length;
}
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import com.example.awesomespring.bo.FileUploadResult;
import com.example.awesomespring.config.MinioConfigProperties;
import com.example.awesomespring.dao.entity.FileUploadRecord;
import com.example.awesomespring.dao.mapper.FileUploadRecordMapper;
import com.example.awesomespring.service.FileService;
import io.minio.*;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.http.HttpServletResponse;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.Paths;
import java.util.Date;
import java.util.UUID;
/**
 * @author zouwei
 * @className FileServiceImpl
 * @date: 2022/8/4 下午3:45
 * @description:
 */
@Service
public class FileServiceImpl implements FileService {
  @Autowired
  private MinioClient client;
  @Autowired
  private MinioConfigProperties properties;
  @Autowired
  private FileUploadRecordMapper fileUploadRecordMapper;
  /**
   * 上传文件
   *
   * @param dirs 目标文件夹； 比如image、video
   * @param file 上传的文件
   * @return
   * @throws Exception
   */
  @Override
  public FileUploadResult putObject(String dirs, MultipartFile file) throws Exception {
    FileUploadResult result = putObject(dirs, file, true);
    // 保存到数据库
    FileUploadRecord row = new FileUploadRecord();
    row.setFileName(result.getFilename());
    row.setCreateTime(new Date());
    row.setFilePath(result.getFilePath());
    row.setContentType(result.getContentType());
    row.setBucketName(result.getBucketName());
    row.setId(UUID.randomUUID().toString());
    row.setSize(result.getLength());
    fileUploadRecordMapper.insert(row);
    return result;
  }
  /**
   * 下载文件并写入响应中
   *
   * @param fileId
   * @param response
   * @throws Exception
   */
  @Override
  public void getObject(String fileId, HttpServletResponse response) throws Exception {
    FileUploadRecord row = fileUploadRecordMapper.selectByPrimaryKey(fileId);
    String path = row.getFilePath();
    // 构建下载参数
    GetObjectArgs objectArgs = GetObjectArgs.builder()
        .bucket(bucketName())
        .object(path)
        .build();
    // 下载并写入响应中
    try (InputStream input = client.getObject(objectArgs); OutputStream outputStream = response.getOutputStream()) {
      response.setContentType(row.getContentType());
      response.setHeader("Accept-Ranges", "bytes");
      response.setHeader("Content-Length", String.valueOf(length));
      response.setHeader("Content-disposition", "attachment; filename=" + filename);
      outputStream.write(input.readAllBytes());
      outputStream.flush();
    } catch (Exception e) {
      // 建议包装成自定义异常，以便自定义异常处理捕获到
      throw e;
    }
  }
  /**
   * 获取文件桶
   *
   * @return
   */
  private String bucketName() {
    return properties.getBucketName();
  }
  /**
   * 如果文件桶不存在就创建
   *
   * @param bucketName
   * @throws Exception
   */
  private void createIfNotExistBucket(String bucketName) throws Exception {
    if (!client.bucketExists(BucketExistsArgs.builder().bucket(bucketName).build())) {
      client.makeBucket(MakeBucketArgs.builder().bucket(bucketName).build());
    }
  }
  /**
   * 这个实现只针对于minio服务实现，所以不建议以接口暴露给外部调用
   *
   * @param dirs
   * @param file
   * @param createIfNotExistBucket
   * @return
   * @throws Exception
   */
  private FileUploadResult putObject(final String dirs, MultipartFile file, boolean createIfNotExistBucket) throws Exception {
    // 获取桶名称
    final String bucketName = bucketName();
    // 获取文件名称
    final String filename = file.getOriginalFilename();
    // 获取文件类型
    final String contentType = file.getContentType();
    // 拼接路径；因为不会把所有文件直接放在桶下面
    String path = filename;
    if (StringUtils.isNotBlank(dirs)) {
      path = Paths.get(dirs, filename).toString();
    }
    // 从上传来的文件中取流
    try (InputStream fileStream = file.getInputStream()) {
      // 如果要求文件桶不存在就创建
      if (createIfNotExistBucket) {
        createIfNotExistBucket(bucketName);
      }
      int length = fileStream.available();
      // 准备好文件上传的参数
      PutObjectArgs objectArgs = PutObjectArgs.builder()
          .bucket(bucketName)
          .object(path)
          .contentType(contentType)
          .stream(fileStream, length, -1)
          .build();
      // 上传文件
      client.putObject(objectArgs);
      // 返回上传结果
      FileUploadResult result = new FileUploadResult();
      result.setContentType(contentType);
      result.setFilePath(dirs);
      result.setFilename(filename);
      result.setBucketName(bucketName);
      result.setLength(length);
      return result;
    } catch (Exception e) {
      // 建议包装成自定义异常，以便自定义异常处理捕获到
      throw e;
    }
  }
}
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