MinIO Java SDK Documentation

To connect to a MinIO service, you need three parameters:

1. Endpoint: The URL of the object storage service.
2. Access Key: A unique identifier for your account (like a user ID).
3. Secret Key: The password for your account.

This example demonstrates how to initialize a MinioClient, check if a bucket exists, create it if it doesn't, and upload a file using putObject.

import java.io.IOException;
import java.security.NoSuchAlgorithmException;
import java.security.InvalidKeyException;

import org.xmlpull.v1.XmlPullParserException;

import io.minio.MinioClient;
import io.minio.errors.MinioException;

public class FileUploader {
  public static void main(String[] args) throws NoSuchAlgorithmException, IOException, InvalidKeyException, XmlPullParserException {
    try {
      // Create a MinioClient using the service URL, Access key, and Secret key
      MinioClient minioClient = new MinioClient("https://play.min.io", "Q3AM3UQ867SPQQA43P2F", "zuf+tfteSlswRu7BJ86wekitnifILbZam1KYY3TG");

      // Check if the bucket exists
      boolean isExist = minioClient.bucketExists("asiatrip");
      if(isExist) {
        System.out.println("Bucket already exists.");
      } else {
        // Create a bucket named 'asiatrip'
        minioClient.makeBucket("asiatrip");
      }

      // Upload a file to the bucket using putObject
      minioClient.putObject("asiatrip","asiaphotos.zip", "/home/user/Photos/asiaphotos.zip");
      System.out.println("/home/user/Photos/asiaphotos.zip is successfully uploaded as asiaphotos.zip to `asiatrip` bucket.");
    } catch(MinioException e) {
      System.out.println("Error occurred: " + e);
    }
  }
}

To connect to an S3 compatible service, you need an Endpoint (URL), an Access Key, and a Secret Key.

This example demonstrates how to use MinioClient to:

1. Initialize a client using the builder pattern.
2. Check if a bucket exists using bucketExists and BucketExistsArgs.
3. Create a bucket if it does not exist using makeBucket and MakeBucketArgs.
4. Upload a local file to a specific bucket and object name using uploadObject and UploadObjectArgs.

import io.minio.BucketExistsArgs;
import io.minio.MakeBucketArgs;
import io.minio.MinioClient;
import io.minio.UploadObjectArgs;
import io.minio.errors.MinioException;
import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

public class FileUploader {
  public static void main(String[] args)
      throws IOException, NoSuchAlgorithmException, InvalidKeyException {
    try {
      // Create a minioClient with the MinIO server playground, its access key and secret key.
      MinioClient minioClient =
          MinioClient.builder()
              .endpoint("https://play.min.io")
              .credentials("Q3AM3UQ867SPQQA43P2F", "zuf+tfteSlswRu7BJ86wekitnifILbZam1KYY3TG")
              .build();

      // Make 'asiatrip' bucket if not exist.
      boolean found =
          minioClient.bucketExists(BucketExistsArgs.builder().bucket("asiatrip").build());
      if (!found) {
        // Make a new bucket called 'asiatrip'.
        minioClient.makeBucket(MakeBucketArgs.builder().bucket("asiatrip").build());
      } else {
        System.out.println("Bucket 'asiatrip' already exists.");
      }

      // Upload '/home/user/Photos/asiaphotos.zip' as object name 'asiaphotos-2015.zip' to bucket
      // 'asiatrip'.
      minioClient.uploadObject(
          UploadObjectArgs.builder()
              .bucket("asiatrip")
              .object("asiaphotos-2015.zip")
              .filename("/home/user/Photos/asiaphotos.zip")
              .build());
      System.out.println(
          "'/home/user/Photos/asiaphotos.zip' is successfully uploaded as "
              + "object 'asiaphotos-2015.zip' to bucket 'asiatrip'.");
    } catch (MinioException e) {
      System.out.println("Error occurred: " + e);
      System.out.println("HTTP trace: " + e.httpTrace());
    }
  }
}

Manage lifecycle rules (e.g., transitions to Glacier or expirations) using setBucketLifecycle(SetBucketLifecycleArgs args) and getBucketLifecycle(GetBucketLifecycleArgs args). To delete the configuration, use deleteBucketLifecycle(DeleteBucketLifecycleArgs args).

// Set lifecycle configuration
List<LifecycleRule> rules = new LinkedList<>();
rules.add(
    new LifecycleRule(
        Status.ENABLED,
        null,
        null,
        new RuleFilter("documents/"),
        "rule1",
        null,
        null,
        new Transition((ZonedDateTime) null, 30, "GLACIER")));
rules.add(
    new LifecycleRule(
        Status.ENABLED,
        null,
        new Expiration((ZonedDateTime) null, 365, null),
        new RuleFilter("logs/"),
        "rule2",
        null,
        null,
        null));
LifecycleConfiguration config = new LifecycleConfiguration(rules);
minioClient.setBucketLifecycle(
    SetBucketLifecycleArgs.builder().bucket("my-bucketname").config(config).build());

// Get lifecycle configuration
LifecycleConfiguration retrievedConfig =
    minioClient.getBucketLifecycle(GetBucketLifecycleArgs.builder().bucket("my-bucketname").build());

Use the MinIOClient.builder() to instantiate a MinioClient. The builder provides several methods to configure the connection to your S3-compatible storage:

• endpoint(...): Configures the service endpoint. It accepts a String (e.g., https://play.min.io), a java.net.URL object, or an okhttp3.HttpUrl object. You can also provide a host, port, and a boolean flag for TLS (e.g., .endpoint("play.min.io", 9000, true)).
• credentials(accessKey, secretKey): Provides the access key (user ID) and secret key (password) for authenticated access.
• region(regionName): Sets the S3 region. If not specified, the region is probed per bucket.
• httpClient(customHttpClient): Allows overriding the default HTTP client with a custom one.

// Create client to S3 service 'play.min.io' at port 9000 with TLS security,
// region 'eu-east-1' and custom HTTP client for authenticated access.
MinioClient minioClient =
    MinioClient.builder()
        .endpoint("https://play.min.io:9000")
        .credentials("Q3AM3UQ867SPQQA43P2F", "zuf+tfteSlswRu7BJ86wekitnifILbZam1KYY3TG")
        .region("eu-east-1")
        .httpClient(customHttpClient)
        .build();

Use listObjects(ListObjectsArgs args) to retrieve object information. This method returns a lazy Iterable<Result<Item>>. You can perform recursive listing, filter by prefix, set a starting point with startAfter, limit results with maxKeys, or include object versions.

// Lists objects information.
Iterable<Result<Item>> results = minioClient.listObjects(
    ListObjectsArgs.builder().bucket("my-bucketname").build());

// Lists objects information recursively.
Iterable<Result<Item>> resultsRecursive = minioClient.listObjects(
    ListObjectsArgs.builder().bucket("my-bucketname").recursive(true).build());

// Lists maximum 100 objects information whose names starts with 'E' and after 'ExampleGuide.pdf'.
Iterable<Result<Item>> resultsFiltered = minioClient.listObjects(
    ListObjectsArgs.builder()
        .bucket("my-bucketname")
        .startAfter("ExampleGuide.pdf")
        .prefix("E")
        .maxKeys(100)
        .build());

// Lists maximum 100 objects information with version whose names starts with 'E' and after 'ExampleGuide.pdf'.
Iterable<Result<Item>> resultsWithVersions = minioClient.listObjects(
    ListObjectsArgs.builder()
        .bucket("my-bucketname")
        .startAfter("ExampleGuide.pdf")
        .prefix("E")
        .maxKeys(100)
        .includeVersions(true)
        .build());