Java Development
Main concepts
In order to access the Odilon server from a Java Application you have to include Odilon client JAR in the classpath. The interaction is managed by an instance of OdilonClient that connects to the server using the credentials: AccessKey (ie. username) and SecretKey (ie. password)
/* these are the default values for the Server */
String endpoint = "http://localhost";
int port = 9234;
String accessKey = "odilon";
String secretKey = "odilon";
/** OdilonClient is the interface, ODClient is the implementation */
OdilonClient client = new ODClient(endpoint, port, accessKey, secretKey);
/** ping checks the status of server, it returns the String "ok" when the server is normal */
String ping = client.ping();
if (!ping.equals("ok")) {
System.out.println("ping error -> " + ping);
System.exit(1);
}
Odilon stores objects using a flat structure of containers called Buckets. A bucket is like a folder, it just contains binary objects, potentially a very large number. Every object contained by a bucket has a unique ObjectName in that bucket; therefore, the pair BucketName + ObjectName is a Unique ID for each object in Odilon.
try {
String bucketName = "bucket-demo";
/** check if the bucket exists, if not create it */
if (client.existsBucket(bucketName))
System.out.println("bucket already exists ->" + bucketName );
else
client.createBucket(bucketName);
} catch (ODClientException e) {
System.out.println(String.valueOf(e.getHttpStatus())+ " " + e.getMessage()+" " + String.valueOf(e.getErrorCode()));
}
Uploading a File requires the Bucket to exist and the ObjectName to be unique for that bucket.
File file = new File("test.pdf");
String bucketName = "bucket-demo";
String objectName = file.getName();
try (InputStream inputStream = new BufferedInputStream(new FileInputStream(file))) {
client.putObjectStream(bucketName, objectName, inputStream, Optional.of(file.getName()), Optional.empty());
} catch (ODClientException e) {
System.out.println(String.valueOf(e.getHttpStatus())+" " + e.getMessage()+" " + String.valueOf(e.getErrorCode()));
} catch (FileNotFoundException | IOException e1) {
System.out.println(e1.getClass().getName() + " " + e1.getMessage());
}
In addition to the binary file, an Object has Metadata (called ObjectMetadata) that is returned by some of the API calls. Odilon allows to retrieve Objects individually by BucketName + ObjectName and also supports to list the contents of a bucket and other simple queries.
try {
/** list all bucket's objects */
ResultSet<Item <ObjectMetadata>> resultSet = client.listObjects(bucket.getName());
while (resultSet.hasNext()) {
Item item = resultSet.next();
if (item.isOk())
System.out.println("ObjectName:"+item.getObject().objectName+" | file: " + item.getObject().fileName);
else
System.out.println(item.getErrorString());
}
} catch (ODClientException e) {
System.out.println(String.valueOf( e.getHttpStatus())+ " "+e.getMessage() + " "+String.valueOf(e.getErrorCode()));
}
Sample programs
Create Bucket
List Buckets
Upload file
Sample putObject and download ObjectMetadata
SamplePutObject.java
List all objects in a Bucket
Get presigned urls of Objects
A presigned URL is a method to grant temporary access to an Object, for example in an HTML webpage.
It remains valid for a limited period of time which is specified when the URL is generated.
This example shows presigned urls that last 7 days and 5 minutes.
SamplePresignedUrl.java
Minio to Odilon migration
This class shows how to migrate from Minio Object Storage to Odilon (it uses Minio SDK 6.x).
It is a multithreaded gateway that iterates reading a buffer of items from Minio and
sending them in parallel to Odilon.
https://github.com/atolomei/miniomigration
