Java upload and download full version tutorial

Preface

Here is a complete example showing how to upload and download files using MinIO and store file information in the databasefilesurface. We will use the Spring Boot framework to implement this functionality.

Project structure

src
├── main
│ ├── java
│ │ └── com
│ │ └── example
│ │ ├── controller
│ │ │ └──
│ │ ├── service
│ │ │ ├──
│ │ │ └──
│ │ ├── repository
│ │ │ └──
│ │ ├── model
│ │ │ └──
│ │ ├── config
│ │ │ └──
│ │ └──
│ └── resources
│ └──

1. Add dependencies

existAdd necessary dependencies to

<dependencies>
    <dependency>
        <groupId></groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId></groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId></groupId>
        <artifactId>minio</artifactId>
        <version>8.3.0</version>
    </dependency>
    <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId></groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
</dependencies>

2. Configure MinIO

existAdd MinIO configuration information to:

=http://localhost:9000
-key=minioadmin
-key=minioadmin
-name=mybucket

=jdbc:h2:mem:testdb
=org.
=sa
=password
-platform=.H2Dialect

3. Create MinioConfig

package ;

import ;
import ;
import ;
import ;

@Configuration
public class MinioConfig {

    @Value("${}")
    private String minioUrl;

    @Value("${-key}")
    private String minioAccessKey;

    @Value("${-key}")
    private String minioSecretKey;

    @Bean
    public MinioClient minioClient() {
        return ()
                .endpoint(minioUrl)
                .credentials(minioAccessKey, minioSecretKey)
                .build();
    }
}

4. Create FileEntity

package ;

import ;
import ;
import ;
import ;

@Entity
public class FileEntity {

    @Id
    @GeneratedValue(strategy = )
    private Long id;
    private String fileName;
    private String fileUrl;

    // Getters and Setters
}

5. Create FileRepository

package ;

import ;
import ;

public interface FileRepository extends JpaRepository<FileEntity, Long> {
}

6. Create FileService

package ;

import ;
import ;

import ;

public interface FileService {
    FileEntity uploadFile(MultipartFile file) throws IOException;
    byte[] downloadFile(String fileName) throws Exception;
}

7. Create FileServiceImpl

package ;

import ;
import ;
import ;
import ;
import ;
import ;
import ;
import ;

import ;
import ;
import ;

@Service
public class FileServiceImpl implements FileService {

    @Autowired
    private MinioClient minioClient;

    @Autowired
    private FileRepository fileRepository;

    @Value("${-name}")
    private String bucketName;

    @Override
    public FileEntity uploadFile(MultipartFile file) throws IOException {
        String fileName = ();
        try {
            (
                    bucketName,
                    fileName,
                    (),
                    ()
            );
            String fileUrl = (bucketName, fileName);

            FileEntity fileEntity = new FileEntity();
            (fileName);
            (fileUrl);

            return (fileEntity);
        } catch (MinioException e) {
            throw new IOException("Error occurred while uploading file to MinIO", e);
        }
    }

    @Override
    public byte[] downloadFile(String fileName) throws Exception {
        try (InputStream stream = (bucketName, fileName);
             ByteArrayOutputStream outputStream = new ByteArrayOutputStream()) {

            byte[] buffer = new byte[1024];
            int length;
            while ((length = (buffer)) != -1) {
                (buffer, 0, length);
            }
            return ();
        } catch (MinioException e) {
            throw new Exception("Error occurred while downloading file from MinIO", e);
        }
    }
}

8. Create FileController

package ;

import ;
import ;
import ;
import ;
import ;
import ;
import .*;
import ;

import ;

@RestController
@RequestMapping("/files")
public class FileController {

    @Autowired
    private FileService fileService;

    @PostMapping("/upload")
    public ResponseEntity<FileEntity> uploadFile(@RequestParam("file") MultipartFile file) throws IOException {
        FileEntity fileEntity = (file);
        return (fileEntity);
    }

    @GetMapping("/download/{fileName}")
    public ResponseEntity<byte[]> downloadFile(@PathVariable String fileName) throws Exception {
        byte[] data = (fileName);
        return ()
                .contentType(MediaType.APPLICATION_OCTET_STREAM)
                .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + fileName + "\"")
                .body(data);
    }
}

9. Main application class

package ;

import ;
import ;

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        (, args);
    }
}

Summarize

Through the above steps, we created a complete Spring Boot application that uses MinIO to upload and download files and store file information in the databasefilesurface. You can pass/files/uploadUpload files on the interface, through/files/download/{fileName}Interface download file.

This is the article about uploading and downloading files with minio in Java. For more related Java uploading and downloading files with minio, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!