AWS S3 File Upload Spring Boot Controller And Service

This blog posts explains on how to upload your file to Amazon S3 services using spring/spring boot.

Prerequisite:

• endpoint Url
• Access Key
• secret Key
• BucketName

Pom.xml file: Here it is spring boot project, so if your is spring then just add the required dependencies for AWS.

<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>

		<!-- https://mvnrepository.com/artifact/com.amazonaws/aws-java-sdk -->
		<dependency>
			<groupId>com.amazonaws</groupId>
			<artifactId>aws-java-sdk</artifactId>
			<version>1.11.545</version>
		</dependency>

		<dependency>
			<groupId>commons-io</groupId>
			<artifactId>commons-io</artifactId>
			<version>2.2</version>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

Spring Controller: This controller provides the way to upload and delete the files from S3.

BucketController.java

@RestController
@RequestMapping("/storage/")
public class BucketController {

    private AmazonClient amazonClient;

    /*@Autowired
    private AmazonS3 s3client;*/
    
    @Autowired
    BucketController(AmazonClient amazonClient) {
        this.amazonClient = amazonClient;
    }

    @PostMapping("/uploadFile")
    public String uploadFile(@RequestPart(value = "file") MultipartFile file) {
        return this.amazonClient.uploadFile(file);
    }
}

AmazonClient: Amazon client service to interact with S3 for both upload and deleting the files.

AmazonClient.java

import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.CannedAccessControlList;
import com.amazonaws.services.s3.model.DeleteObjectRequest;
import com.amazonaws.services.s3.model.PutObjectRequest;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.PostConstruct;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Date;

@Service
public class AmazonClient {

    private AmazonS3 s3client;

    @Value("${amazonProperties.endpointUrl}")
    private String endpointUrl;
    @Value("${amazonProperties.bucketName}")
    private String bucketName;
    @Value("${amazonProperties.accessKey}")
    private String accessKey;
    @Value("${amazonProperties.secretKey}")
    private String secretKey;

    @PostConstruct
    private void initializeAmazon() {
        AWSCredentials credentials = new BasicAWSCredentials(this.accessKey, this.secretKey);
        this.s3client = new AmazonS3Client(credentials);
    }

    public String uploadFile(MultipartFile multipartFile) {
        String fileUrl = "";
        try {
            File file = convertMultiPartToFile(multipartFile);
            String fileName = generateFileName(multipartFile);
            fileUrl = endpointUrl + "/" + bucketName + "/" + fileName;
            uploadFileTos3bucket(fileName, file);
            file.delete();
        } catch (Exception e) {
           e.printStackTrace();
        }
        return fileUrl;
    }

    private File convertMultiPartToFile(MultipartFile file) throws IOException {
        File convFile = new File(file.getOriginalFilename());
        FileOutputStream fos = new FileOutputStream(convFile);
        fos.write(file.getBytes());
        fos.close();
        return convFile;
    }

    private String generateFileName(MultipartFile multiPart) {
        return new Date().getTime() + "-" + multiPart.getOriginalFilename().replace(" ", "_");
    }

    private void uploadFileTos3bucket(String fileName, File file) {
        s3client.putObject(new PutObjectRequest(bucketName, fileName, file)
                .withCannedAcl(CannedAccessControlList.PublicRead));
    }

    public String deleteFileFromS3Bucket(String fileUrl) {
        String fileName = fileUrl.substring(fileUrl.lastIndexOf("/") + 1);
        s3client.deleteObject(new DeleteObjectRequest(bucketName, fileName));
        return "Successfully deleted";
    }
}

If you are using yml then below is your application.yml file with aws s3 properties, otherwise you can create s3.properties file and load it in your spring service.

amazonProperties:
endpointUrl: YOUR_ENDPOINT
accessKey: YOUR_ACCESS_KEY_GENERALLY_20_DIGITS
secretKey: YOUR_SECRET_KEY_GENERALLY_40_DIGITS
bucketName: YOUR_BUCKET_NAME

server:
port: APPLICATION_RUNNING_PORT
contextPath: /s3manager