Hackforge Academy

Explanation

AWS S3 stores files inside buckets. A bucket can contain images, PDFs, videos, reports, and other objects.

Code:

AWS S3 Bucket
  ├── profile-images/
  ├── invoices/
  ├── resumes/
  └── documents/

Explanation

Add the AWS SDK dependency to communicate with Amazon S3 from a Spring Boot application.

Code:

<dependency>
  <groupId>software.amazon.awssdk</groupId>
  <artifactId>s3</artifactId>
</dependency>

Explanation

Create an S3 client using the AWS SDK. Credentials should be provided through IAM roles, environment variables, or the AWS credentials provider chain.

Code:

S3Client s3Client = S3Client.builder()
    .region(Region.AP_SOUTH_1)
    .build();

Explanation

Upload a MultipartFile to an S3 bucket by creating a PutObjectRequest and sending the file bytes.

Code:

public String uploadFile(MultipartFile file)
        throws IOException {

    PutObjectRequest request = PutObjectRequest.builder()
        .bucket(bucketName)
        .key(file.getOriginalFilename())
        .contentType(file.getContentType())
        .build();

    s3Client.putObject(request,
        RequestBody.fromBytes(file.getBytes()));

    return file.getOriginalFilename();
}

Explanation

Expose a REST endpoint that accepts a file from the client and sends it to the S3 service.

Code:

@PostMapping("/upload")
public String upload(@RequestParam MultipartFile file)
        throws IOException {
    return s3Service.uploadFile(file);
}