Java SDK

This guide details the steps needed to install and use the AWS SDK For Java.

The AWS SDK for Java simplifies use of AWS Services by providing a set of libraries that are consistent and familiar for Java developers. It provides support for API lifecycle considerations such as credential management, retries, data marshaling, and serialization. The AWS SDK for Java also supports higher-level abstractions for simplified development.

Using Java SDK

To use Java SDK, you must first import all necessary packages. After that, you need to set up an S3 client to connect to your bucket. Provide your access key, secret key, and path to your files.

import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.client.builder.AwsClientBuilder;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.S3Object;
import com.amazonaws.services.s3.model.PutObjectRequest;
import com.amazonaws.services.s3.model.CannedAccessControlList;
import com.amazonaws.services.s3.model.S3ObjectSummary;
import com.amazonaws.services.s3.model.S3ObjectInputStream;

import java.io.File;
import java.util.List;
import java.io.IOException;
import java.io.FileOutputStream;

//Let's create S3 client
String accessKey = "Your access key";
String secretKey = "Your secret key";
String endpointUrl = "http://s3.tebi.io";
String region = "US";
String bucketName = "Your bucket name";
String bucketFilePath = "This is the path in your bucket";
String filePath = "This is the your local path";

BasicAWSCredentials credentials = new BasicAWSCredentials(accessKey, secretKey);

AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
        .withEndpointConfiguration(new AwsClientBuilder.EndpointConfiguration(endpointUrl, region))
        .withCredentials(new AWSStaticCredentialsProvider(credentials))
        .enablePathStyleAccess()
        .build();

Now, after we have an S3 client, we can start sending files to our bucket:

PutObjectRequest request = new PutObjectRequest(bucketName, bucketFilePath, new File(filePath));
request.setCannedAcl(CannedAccessControlList.PublicRead);

s3Client.putObject(request);

System.out.println("File uploaded successfully!");

Or you can download a file from your bucket:

S3Object s3Object = s3Client.getObject(bucketName, bucketFilePath);

S3ObjectInputStream objectInputStream = s3Object.getObjectContent();

// Save the object content to a local file
try (FileOutputStream fileOutputStream = new FileOutputStream(new File(filePath))) {
    byte[] buffer = new byte[1024];
    int bytesRead;
    while ((bytesRead = objectInputStream.read(buffer)) != -1) {
        fileOutputStream.write(buffer, 0, bytesRead);
    }
    System.out.println("File retrieved and saved successfully!");
} catch (IOException e) {
    e.printStackTrace();
}

Also, you can get a list of objects inside your bucket:

List<S3ObjectSummary> objectSummaries = s3Client.listObjects(bucketName).getObjectSummaries();

// Print the names of the objects
System.out.println("Objects in bucket " + bucketName + ":");
for (S3ObjectSummary objectSummary : objectSummaries) {
    System.out.println("- " + objectSummary.getKey());
}

For more examples, please refer to the official SDK documentation examples. Full AWS Java SDK reference is available here.