I have a Java object. I get this as a response from an underlying API of our system. I need to store this object in a folder inside an S3 bucket.
I found this 
If you are not familiar with using the AWS SDK for Java V2, refer to the Java V2 DEV Guide for all the concepts you need. For example, how to work with Credentials.
S3Client
The following code shows you how to use this object to upload content.
package com.example.s3;
// snippet-start:[s3.java2.s3_object_upload.import]
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
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;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
// snippet-end:[s3.java2.s3_object_upload.import]
/**
* Before running this Java V2 code example, set up your development environment, including your credentials.
*
* For more information, see the following documentation topic:
*
* https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
*/
public class PutObject {
public static void main(String[] args) {
final String usage = "\n"
"Usage:\n"
" <bucketName> <objectKey> <objectPath> \n\n"
"Where:\n"
" bucketName - The Amazon S3 bucket to upload an object into.\n"
" objectKey - The object to upload (for example, book.pdf).\n"
" objectPath - The path where the file is located (for example, C:/AWS/book2.pdf). \n\n" ;
if (args.length != 3) {
System.out.println(usage);
System.exit(1);
}
String bucketName =args[0];
String objectKey = args[1];
String objectPath = args[2];
System.out.println("Putting object " objectKey " into bucket " bucketName);
System.out.println(" in bucket: " bucketName);
ProfileCredentialsProvider credentialsProvider = ProfileCredentialsProvider.create();
Region region = Region.US_EAST_1;
S3Client s3 = S3Client.builder()
.region(region)
.credentialsProvider(credentialsProvider)
.build();
String result = putS3Object(s3, bucketName, objectKey, objectPath);
System.out.println("Tag information: " result);
s3.close();
}
// snippet-start:[s3.java2.s3_object_upload.main]
public static String putS3Object(S3Client s3,
String bucketName,
String objectKey,
String objectPath) {
try {
Map<String, String> metadata = new HashMap<>();
metadata.put("x-amz-meta-myVal", "test");
PutObjectRequest putOb = PutObjectRequest.builder()
.bucket(bucketName)
.key(objectKey)
.metadata(metadata)
.build();
PutObjectResponse response = s3.putObject(putOb,
RequestBody.fromBytes(getObjectFile(objectPath)));
return response.eTag();
} catch (S3Exception e) {
System.err.println(e.getMessage());
System.exit(1);
}
return "";
}
// Return a byte array.
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;
}
// snippet-end:[s3.java2.s3_object_upload.main]
}
TransferManager object
The following code shows you how to use this Java object to upload content to an S3 bucket.
package com.example.transfermanager;
import software.amazon.awssdk.auth.credentials.EnvironmentVariableCredentialsProvider;
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.transfer.s3.FileUpload;
import software.amazon.awssdk.transfer.s3.S3TransferManager;
import java.nio.file.Paths;
/**
* Before running this Java V2 code example, set up your development environment, including your credentials.
*
* For more information, see the following documentation topic:
*
* https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
*/
public class UploadObject {
public static void main(String[] args) {
final String usage = "\n"
"Usage:\n"
" <bucketName> <objectKey> <objectPath> \n\n"
"Where:\n"
" bucketName - The Amazon S3 bucket to upload an object into.\n"
" objectKey - The object to upload (for example, book.pdf).\n"
" objectPath - The path where the file is located (for example, C:/AWS/book2.pdf). \n\n" ;
if (args.length != 3) {
System.out.println(usage);
System.exit(1);
}
long mb = 1024;
String bucketName = args[0];
String objectKey = args[1];
String objectPath = args[2];
System.out.println("Putting an object into bucket " bucketName " using the S3TransferManager");
ProfileCredentialsProvider credentialsProvider = ProfileCredentialsProvider.create();
Region region = Region.US_EAST_1;
S3TransferManager transferManager = S3TransferManager.builder()
.s3ClientConfiguration(cfg ->cfg.region(region)
.credentialsProvider(credentialsProvider)
.targetThroughputInGbps(20.0)
.minimumPartSizeInBytes(10 * mb))
.build();
uploadObjectTM(transferManager, bucketName, objectKey, objectPath);
System.out.println("Object was successfully uploaded using the Transfer Manager.");
transferManager.close();
}
public static void uploadObjectTM( S3TransferManager transferManager, String bucketName, String objectKey, String objectPath) {
FileUpload upload =
transferManager.uploadFile(u -> u.source(Paths.get(objectPath))
.putObjectRequest(p -> p.bucket(bucketName).key(objectKey)));
upload.completionFuture().join();
}
}
Another Update
Look at this line of code:
PutObjectResponse response = s3.putObject(putOb, RequestBody.fromBytes(getObjectFile(objectPath)));
As long as you get your data you want to upload to a byte array, you can upload it to Amazon S3 using this code. I used a physical PDF file as an example. But if you get the byte[] from another source it still works.
The RequestBody supports other methods too as discussed in these Javadocs.
https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/core/sync/RequestBody.html
Hope this clears up your doubt.