AWS Java SDK 사용 방법

AWS Java SDK를 사용하여 오브젝트 스토리지를 사용하는 방법은 아래와 같습니다.

1. AWS Java v2 S3 SDK 사용하기

AWS Java v2 S3 SDK는 AWS에서 Java 코드를 통해 S3를 이용할 수 있도록 제공하는 도구입니다.

카페24 클라우드의 오브젝트 스토리지는 S3 API와 호환이 되므로 해당 SDK 사용이 가능합니다.

매뉴얼 테스트 버전	Java v2 S3 SDK 참고 링크
AWS Java SDK version : 2.17.230 Java version : 11.0.11	문서 : Developer guide - AWS SDK for Java 2.x 예제 : Java v2 S3 examples

2. AWS Java v2 S3 SDK 설치하기

Maven 프로젝트의 pom.xml에 dependency를 추가합니다.

<dependency>
    <groupId>software.amazon.awssdk</groupId>
    <artifactId>bom</artifactId>
    <version>2.17.230</version>
    <type>pom</type>
    <scope>import</scope>
</dependency>

3. 오브젝트 스토리지 API Key 확인하기

[오브젝트 스토리지 사용 방법]을 참고하여 신청한 오브젝트 스토리지의 Access Key와 Secret Key를 확인합니다.

4. 자격 증명 프로필 설정하기

인증 파일을 생성하여 Access Key와 Secret Key를 등록합니다.

자세한 정보는 AWS SDK for Java v2 - Using Credentials에서 확인할 수 있습니다.

인증 파일의 기본 경로는 "~/.aws/credentials"입니다.

$ cat >> ~/.aws/credentials << EOF
[default]
aws_access_key_id = [access_key]
aws_secret_access_key = [secret_key]
EOF

5. 코드 예제

주의사항

사용하는 Java 및 SDK 버전에 따라 변경이 필요할 수 있습니다.

해당 내용은 AWS Java SDK를 사용하여 카페24 클라우드의 오브젝트 스토리지를 이용하는 예제 코드로, 필요에 따라 응용할 수 있습니다.

(1) 버킷 생성

버킷을 생성합니다.

package cafe24.demo;

import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.core.waiters.WaiterResponse;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.CreateBucketRequest;
import software.amazon.awssdk.services.s3.model.HeadBucketRequest;
import software.amazon.awssdk.services.s3.model.HeadBucketResponse;
import software.amazon.awssdk.services.s3.model.S3Exception;
import software.amazon.awssdk.services.s3.waiters.S3Waiter;
import java.net.URI;

public class bucket_create {
    public static void main(String[] args) {
        final String endpoint_url = "https://kr.cafe24obs.com";
        final String region_name = "kr1";
        String bucketName = "test-bucket";
        Region newRegion = Region.of(region_name);
        ProfileCredentialsProvider credentialsProvider = ProfileCredentialsProvider.create();

        S3Client s3Client = S3Client.builder()
            .region(newRegion)
            .endpointOverride(URI.create(endpoint_url))
            .credentialsProvider(credentialsProvider)
            .build();

        System.out.format("Creating a bucket named %s\n", bucketName);
            try {
                S3Waiter s3Waiter = s3Client.waiter();
                CreateBucketRequest bucketRequest = CreateBucketRequest.builder()
                    .bucket(bucketName)
                    .build();
    
                s3Client.createBucket(bucketRequest);
                HeadBucketRequest bucketRequestWait = HeadBucketRequest.builder()
                    .bucket(bucketName)
                    .build();
                
                // 버킷이 생성되기까지 대기
                WaiterResponse<HeadBucketResponse> waiterResponse = s3Waiter.waitUntilBucketExists(bucketRequestWait);
                waiterResponse.matched().response().ifPresent(System.out::println);
                System.out.println(bucketName +" has been created.");
            } catch (S3Exception e) {
                System.err.println(e.awsErrorDetails().errorMessage());
                System.exit(1);
            }
            s3Client.close();
    }
}

output 예시는 다음과 같습니다.

Bucket [test-bucket] has been created.

(2) 버킷 삭제

오브젝트가 모두 삭제된 빈 버킷에 대해서만 삭제가 가능합니다.

package cafe24.demo;

import java.net.URI;
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.DeleteBucketRequest;
import software.amazon.awssdk.services.s3.model.DeleteObjectRequest;
import software.amazon.awssdk.services.s3.model.ListObjectsV2Request;
import software.amazon.awssdk.services.s3.model.ListObjectsV2Response;
import software.amazon.awssdk.services.s3.model.S3Exception;
import software.amazon.awssdk.services.s3.model.S3Object;

public class bucket_delete {
    public static void main(String[] args) {
        final String endpoint_url = "https://kr.cafe24obs.com";
        final String region_name = "kr1";
        Region newRegion = Region.of(region_name);
        ProfileCredentialsProvider credentialsProvider = ProfileCredentialsProvider.create();
        String bucketName = "test-bucket";

        S3Client s3Client = S3Client.builder()
                .region(newRegion)
                .endpointOverride(URI.create(endpoint_url))
                .credentialsProvider(credentialsProvider)
                .build();
       
        try {
            // 버킷 삭제를 위해 버킷에 있는 모든 오브젝트 삭제
            ListObjectsV2Request listObjectsV2Request = ListObjectsV2Request.builder()
                    .bucket(bucketName)
                    .build();
            ListObjectsV2Response listObjectsV2Response;

            do {
                listObjectsV2Response = s3Client.listObjectsV2(listObjectsV2Request);
                for (S3Object s3Object : listObjectsV2Response.contents()) {
                    DeleteObjectRequest request = DeleteObjectRequest.builder()
                            .bucket(bucketName)
                            .key(s3Object.key())
                            .build();
                    s3Client.deleteObject(request);
                }
            } while (listObjectsV2Response.isTruncated());
            System.out.println("All objects in the bucket are deleted.");

            // 비어 있는 버킷 삭제
            DeleteBucketRequest deleteBucketRequest = DeleteBucketRequest.builder().bucket(bucketName).build();
            s3Client.deleteBucket(deleteBucketRequest);
            System.out.println("Bucket ["+bucketName+"] has been deleted.");
            
        } catch (S3Exception e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
}

output 예시는 다음과 같습니다.

All objects in the bucket are deleted.
Bucket [test-bucket] has been deleted.

(3) 버킷 리스트 조회

존재하는 모든 버킷을 조회합니다.

package cafe24.demo;

import java.net.URI;
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.ListBucketsRequest;
import software.amazon.awssdk.services.s3.model.ListBucketsResponse;

public class bucket_list {
    public static void main(String[] args) {
        final String endpoint_url = "https://kr.cafe24obs.com";
        final String region_name = "kr1";
        Region newRegion = Region.of(region_name);
        ProfileCredentialsProvider credentialsProvider = ProfileCredentialsProvider.create();

        S3Client s3Client = S3Client.builder()
            .region(newRegion)
            .endpointOverride(URI.create(endpoint_url))
            .credentialsProvider(credentialsProvider)
            .build();
            
        System.out.println("--Existing buckets--");
        ListBucketsRequest listBucketsRequest = ListBucketsRequest.builder().build();
        ListBucketsResponse listBucketsResponse = s3Client.listBuckets(listBucketsRequest);
        listBucketsResponse.buckets().stream().forEach(x -> System.out.println("Name : " +x.name()+ " CreationDate : " + x.creationDate()));
        s3Client.close();
    }
}

output 예시는 다음과 같습니다.

--Existing buckets--
Name : test-bucket CreationDate : 2022-12-30T01:44:29.104Z
Name : test-bucket1 CreationDate : 2022-12-29T06:04:09.457Z
Name : test-bucket2 CreationDate : 2022-12-29T06:04:16.613Z

(4) 오브젝트 업로드

로컬에 있는 파일을 특정 버킷에 업로드합니다.

파일 업로드 시에 파일의 contentType은 기본으로 binary/octet-stream으로 지정됩니다.

특정 타입으로 업로드 하기 위해서는 PutObjectRequest 객체에 contentType 정보를 담아야 합니다.

package cafe24.demo;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URI;
import java.nio.file.Paths;
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.awscore.exception.AwsServiceException;
import software.amazon.awssdk.core.exception.SdkClientException;
import software.amazon.awssdk.core.sync.RequestBody;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.PutObjectRequest;
import software.amazon.awssdk.services.s3.model.PutObjectResponse;
import software.amazon.awssdk.services.s3.model.S3Exception;

public class object_upload {
    public static void main(String[] args) throws S3Exception, AwsServiceException, SdkClientException, IOException {
        final String endpoint_url = "https://kr.cafe24obs.com";
        final String region_name = "kr1";
        Region newRegion = Region.of(region_name);
        ProfileCredentialsProvider credentialsProvider = ProfileCredentialsProvider.create();
        String bucketName = "test-bucket";

        //업로드할 파일의 로컬 경로
        String filePath = "demo\\src\\main\\java\\cafe24\\demo\\files\\test-file.txt";
        String keyName = Paths.get(filePath).getFileName().toString();

        //업로드할 파일의 contentType 지정
        String contentType = "text/plain";
  
        S3Client s3Client = S3Client.builder()
                .region(newRegion)
                .endpointOverride(URI.create(endpoint_url))
                .credentialsProvider(credentialsProvider)
                .build();

        PutObjectRequest objectRequest = PutObjectRequest.builder()
                .bucket(bucketName)
                .contentType(contentType)
                .key(keyName)
                .build();

        PutObjectResponse response = s3Client.putObject(objectRequest, RequestBody.fromBytes(getObjectFile(filePath)));
        System.out.println(response);
        System.out.println("Object ["+keyName+"] has been uploaded to the bucket ["+bucketName+"].");
    }
    private static byte[] getObjectFile(String filePath) {
        FileInputStream fileInputStream = null;
        byte[] bytesArray = null;

        try {
            File file = new File(filePath);
            bytesArray = new byte[(int) file.length()];
            fileInputStream = new FileInputStream(file);
            fileInputStream.read(bytesArray);

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (fileInputStream != null) {
                try {
                    fileInputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return bytesArray;
    }
}

output 예시는 다음과 같습니다.

PutObjectResponse(ETag="056f5ca5dbd6a49717737a6e4ede4f78")
Object [test-file.txt] has been uploaded to the bucket [test-bucket].

(5) 오브젝트 다운로드

버킷에 있는 파일을 로컬의 특정 경로로 다운로드합니다.

다운받으려는 경로에 동일한 이름의 파일이 있으면 다운로드 실패합니다.

package cafe24.demo;

import java.io.IOException;
import java.net.URI;
import java.nio.file.Path;
import java.nio.file.Paths;
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.awscore.exception.AwsServiceException;
import software.amazon.awssdk.core.exception.SdkClientException;
import software.amazon.awssdk.core.sync.ResponseTransformer;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.GetObjectRequest;
import software.amazon.awssdk.services.s3.model.S3Exception;

public class object_download {
    public static void main(String[] args) throws S3Exception, AwsServiceException, SdkClientException, IOException {
        final String endpoint_url = "https://kr.cafe24obs.com";
        final String region_name = "kr1";
        Region newRegion = Region.of(region_name);
        ProfileCredentialsProvider credentialsProvider = ProfileCredentialsProvider.create();
        String bucketName = "test-bucket";
        String keyName = "test-file.txt";

        //오브젝트를 다운로드할 경로
        Path destination =  Paths.get("demo\\src\\main\\java\\cafe24\\demo\\files\\downloaded-file.txt");

        S3Client s3Client = S3Client.builder()
                .region(newRegion)
                .endpointOverride(URI.create(endpoint_url))
                .credentialsProvider(credentialsProvider)
                .build();

        GetObjectRequest getObjectRequest = GetObjectRequest.builder()
                .bucket(bucketName)
                .key(keyName)
                .build();

        s3Client.getObject(getObjectRequest, ResponseTransformer.toFile(destination));
        System.out.println("Object has been downloaded to local. \n Downloaded Path : ["+destination+"]");
    }
}

output 예시는 다음과 같습니다.

Object has been downloaded to local. 
 Downloaded Path : [demo\src\main\java\cafe24\demo\files\downloaded-file.txt]

(6) 오브젝트 리스트 조회

버킷에 있는 모든 파일과 폴더를 조회합니다.

package cafe24.demo;

import java.net.URI;
import java.util.List;
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.ListObjectsRequest;
import software.amazon.awssdk.services.s3.model.ListObjectsResponse;
import software.amazon.awssdk.services.s3.model.S3Exception;
import software.amazon.awssdk.services.s3.model.S3Object;

public class object_get_list {
    public static void main(String[] args) {
        final String endpoint_url = "https://kr.cafe24obs.com";
        final String region_name = "kr1";
        String bucketName = "test-bucket";
        Region newRegion = Region.of(region_name);
        ProfileCredentialsProvider credentialsProvider = ProfileCredentialsProvider.create();

        S3Client s3Client = S3Client.builder()
                .region(newRegion)
                .endpointOverride(URI.create(endpoint_url))
                .credentialsProvider(credentialsProvider)
                .build();
                
        System.out.println("Get list of all objects in the bucket.");
        
        try {
            ListObjectsRequest listObjects = ListObjectsRequest
                    .builder()
                    .bucket(bucketName)
                    .build();

            ListObjectsResponse res = s3Client.listObjects(listObjects);
            List<S3Object> objects = res.contents();
            
            if (objects == null || objects.isEmpty()) {
                System.out.println("The bucket is empty.");
                return;
            }
            
            for (S3Object value : objects) {
                System.out.print("\n Name : " + value.key() + "\tSize : " + calKb(value.size()) + "KBs\tOwner ID : "
                        + value.owner().id());
            }
        } catch (S3Exception e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
        s3Client.close();
    }
    // bytes를 kbs로 변환
    private static long calKb(Long val) {
        return val / 1024;
    }
}

output 예시는 다음과 같습니다.

Get list of all objects in the bucket.
 Name : folder/    Size : 0KBs    Owner ID : clouduser
 Name : folder/test-file-04    Size : 4KBs    Owner ID : clouduser
 Name : folder/test-file-05    Size : 4KBs    Owner ID : clouduser
 Name : folder/test-file-06    Size : 4KBs    Owner ID : clouduser
 Name : test-file-01    Size : 4KBs    Owner ID : clouduser
 Name : test-file-02    Size : 4KBs    Owner ID : clouduser
 Name : test-file-03    Size : 4KBs    Owner ID : clouduser

(7) 오브젝트 삭제

특정 버킷에 있는 파일을 삭제합니다.

package cafe24.demo;

import java.net.URI;
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.DeleteObjectRequest;

public class object_delete {
    public static void main(String[] args) {
        final String endpoint_url = "https://kr.cafe24obs.com";
        final String region_name = "kr1";
        Region newRegion = Region.of(region_name);
        ProfileCredentialsProvider credentialsProvider = ProfileCredentialsProvider.create();
        String bucketName = "test-bucket";
        String fileName = "test-file.txt";
        
        S3Client s3Client = S3Client.builder()
                .region(newRegion)
                .endpointOverride(URI.create(endpoint_url))
                .credentialsProvider(credentialsProvider)
                .build();
                
        DeleteObjectRequest deleteObjectRequest = DeleteObjectRequest.builder()
                .bucket(bucketName)
                .key(fileName)
                .build();

        s3Client.deleteObject(deleteObjectRequest);
        System.out.println("Object ["+fileName+"] has been deleted from the bucket.");
    }
}

output 예시는 다음과 같습니다.

Object [test-file.txt] has been deleted from the bucket.

(8) 오브젝트 복사

파일을 다른 버킷으로 복사합니다.

package cafe24.demo;

import java.net.URI;
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.CopyObjectRequest;
import software.amazon.awssdk.services.s3.model.CopyObjectResponse;
import software.amazon.awssdk.services.s3.model.S3Exception;

public class object_copy {
    public static void main(String[] args) {
        final String endpoint_url = "https://kr.cafe24obs.com";
        final String region_name = "kr1";
        Region newRegion = Region.of(region_name);
        ProfileCredentialsProvider credentialsProvider = ProfileCredentialsProvider.create();

        // 복사하려는 오브젝트의 이름
        String objectKey = "bucket1-file.txt";
        // 복사하려는 오브젝트가 위치한 버킷
        String fromBucket = "test-bucket1";
        // 붙여넣기 할 버킷
        String toBucket = "test-bucket";

        S3Client s3Client = S3Client.builder()
        .region(newRegion)
        .endpointOverride(URI.create(endpoint_url))
        .credentialsProvider(credentialsProvider)
        .build();
        
        CopyObjectRequest copyReq = CopyObjectRequest.builder()
            .sourceKey(objectKey)
            .sourceBucket(fromBucket) 
            .destinationBucket(toBucket)
            .destinationKey(objectKey)
            .build();

        try {
            CopyObjectResponse copyRes = s3Client.copyObject(copyReq);
            System.out.println("Copying object ["+objectKey+"] from ["+fromBucket+"] to ["+toBucket+"] has been completed");
            System.out.println(copyRes.copyObjectResult().toString());        
        } catch (S3Exception e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }
}

output 예시는 다음과 같습니다.

Copying object [bucket1-file.txt] from [test-bucket1] to [test-bucket] has been completed
CopyObjectResult(ETag=d9ebe4d6aeb33dea41ddb2b57e7b6d80, LastModified=2023-01-03T18:05:31.688Z)