> For the complete documentation index, see [llms.txt](https://docs.4everland.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.4everland.org/storage/bucket/bucket-api-s3-compatible/coding-examples/aws-sdk-java.md).

# AWS SDK - Java

Please read the following to understand how to use the AWS SDK - Java with the 4EVERLAND Bucket. Combine the AWS SDK API for the Java language with the 4EVERLAND Bucket to achieve file uploads to the IPFS or Arweave storage networks.

## Preparation

* In your development environment, [download and install](https://www.java.com/download/ie_manual.jsp) Java.
* [Download and install](https://github.com/aws/aws-sdk-go#getting-started) the AWS SDK for Java.
* [Register](https://www.4everland.org/) a free 4EVERLAND account.
* If you need to use Arweave storage, you need to create an Arweave bucket. Click to[ ](https://docs.4everland.org/storage/bucket/bucket-api-s3-compatible)[learn more](https://docs.4everland.org/storage/bucket/guides).
* To obtain the corresponding API key in the bucket, click to[ learn more](https://docs.4everland.org/storage/bucket/bucket-api-s3-compatible).

## Development Examples

### Create a bucket

`bucketName`: The desired bucket name to create

`accessKey`: Bucket-Access Keys-API key

`secretKey`: Bucket-Access Keys-API Secret

`endpoint_url`: <https://endpoint.4everland.co>

`region`: Default filled in with "4everland"

```java
import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.CreateBucketRequest;
import com.amazonaws.services.s3.model.GetBucketLocationRequest;

import java.io.IOException;

public class CreateBucket2 {

    public static void main(String[] args) throws IOException {
        String bucketName = "new-bucketname";
        String accessKey = "4EVERLAND-Bucket-APIKey";
        String secretKey = "4EVERLAND-Bucket-APISecret";
        String endpoint_url = "https://endpoint.4everland.co";
        String region = "4everland";
        try {
            AmazonS3ClientBuilder.standard();
            AWSCredentials credentials = new BasicAWSCredentials(accessKey,secretKey);
            AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                    .withCredentials(credentials)
                    .withEndpointConfiguration(new AwsClientBuilder.EndpointConfiguration(endpoint_url, region))
                    .build();

            if (!s3Client.doesBucketExistV2(bucketName)) {
                s3Client.createBucket(new CreateBucketRequest(bucketName));

                String bucketLocation = s3Client.getBucketLocation(new GetBucketLocationRequest(bucketName));
                System.out.println("Bucket location: " + bucketLocation);
            }
        } catch (AmazonServiceException e) {
            e.printStackTrace();
        } catch (SdkClientException e) {
            e.printStackTrace();
        }
    }
}
```

### Upload a file

`bucketName`: Your bucket name

`stringObjKeyName`: The name of the file to be uploaded

`fileObjKeyName`: The name of the file to be uploaded

`fileName`: The path of the file to be uploaded

`accessKey`: Bucket-Access Keys-API key

`secretKey`: Bucket-Access Keys-API Secret

`endpoint_url`: <https://endpoint.4everland.co>

`region:` Default filled in with "4everland"

```java
import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.ObjectMetadata;
import com.amazonaws.services.s3.model.PutObjectRequest;

import java.io.File;
import java.io.IOException;

public class UploadObject {

    public static void main(String[] args) throws IOException {
        String bucketName = "4everland-bucketname";
        String stringObjKeyName = "object-name";
        String fileObjKeyName = "object-name";
        String fileName = "/path/to/4everland/4ever.png";
        String accessKey = "4EVERLAND-Bucket-APIKey";
        String secretKey = "4EVERLAND-Bucket-APISecret";
        String endpoint_url = "https://endpoint.4everland.co";
        String region = "4everland";

        try {
            AWSCredentials credentials = new BasicAWSCredentials(accessKey,secretKey);
            AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                    .withCredentials(credentials)
                    .withEndpointConfiguration(new AwsClientBuilder.EndpointConfiguration(endpoint_url, region))
                    .build();

            s3Client.putObject(bucketName, stringObjKeyName, "Uploaded String Object");

            PutObjectRequest request = new PutObjectRequest(bucketName, fileObjKeyName, new File(fileName));
            ObjectMetadata metadata = new ObjectMetadata();
            metadata.setContentType("plain/text");
            metadata.addUserMetadata("title", "someTitle");
            request.setMetadata(metadata);
            s3Client.putObject(request);
        } catch (AmazonServiceException e) {

            e.printStackTrace();
        } catch (SdkClientException e) {
            e.printStackTrace();
        }
    }
}
```

### Requesting IPFS CID and Arweave Hash

`bucket`: The bucket name where the target file is stored

`key`: The name of the target file

```java
HeadObjectRequest headObjectRequest = HeadObjectRequest.builder()
  .bucket("4everland-bucketname")
  .key("your-object-name")
  .build();
  
HeadObjectResponse headObjectResponse = s3Client.headObject(headObjectRequest);
System.out.println("ipfs hash: " + headObjectResponse.metadata().get("ipfs-hash");
//If it is an Arweave type of bucket.
System.out.println("arweave hash: " + headObjectResponse.metadata().get("arweave-hash");
```

{% hint style="info" %}
If you have any questions, please join our [Discord server](https://discord.com/invite/Cun2VpsdjF), or send us an email at <contact@4everland.org>.
{% endhint %}