如何在没有 mapr 客户端的情况下从 Java 程序连接到 MaprDB (Hbase)

Question

I know how to talk to MaprDB from Java program with Mapr client installed. But, want to know how can I connect to MaprDB without Mapr client installed? Is there a pure Java API (ie without needing to install any other software, just using some jars) for my requirement?

Please note - these are binary tables (and not JSON tables).

Answer 1

There is an approach that you can use.

The so-called DAG (data access gateway) is a gRPC-based gateway that you can use. There is a pure Java client for this. Performance impact is significant, but not massive and the API is the same OJAI API as when you access the database using the thick client.

See the following links for more information:

https://mapr.com/docs/61/MapROverview/MapRDataAccessGateway.html https://mapr.com/docs/61/AdvancedInstallation/InstallingDataAccessGateway.html https://mapr.com/docs/61/AdministratorGuide/AdminMapRDataAccessGateway.html https://mapr.com/docs/61/EcosystemRN/MapR_Data_Access_Gateway_2.0_release_notes.html

Answer 2

Depends upon your definition of "without needing to install any other software".

You don't need to install the mapr-client package to access the MapR Cluster from a Java application - the MapR jars can be installed to your preferred location on the classpath or even shaded into an "uber" jar.

But you do need to be running on a supported client platform (Linux x86-64, MacOS x86-64, Windows i386 or x86-64), because the maprfs jar does contain JNI libraries packaged within it that it unpacks at initialisation time.