read data from HBase by using Spark with JAVA

Question

I want to access HBase via Spark using JAVA. I have not found any examples for this besides this one. In the answer is written,

You can also write this in Java

I copied this code from How to read from hbase using spark :

import org.apache.hadoop.hbase.client.{HBaseAdmin, Result}
import org.apache.hadoop.hbase.{ HBaseConfiguration, HTableDescriptor }
import org.apache.hadoop.hbase.mapreduce.TableInputFormat
import org.apache.hadoop.hbase.io.ImmutableBytesWritable

import org.apache.spark._

object HBaseRead {
  def main(args: Array[String]) {
    val sparkConf = new SparkConf().setAppName("HBaseRead").setMaster("local[2]")
    val sc = new SparkContext(sparkConf)
    val conf = HBaseConfiguration.create()
    val tableName = "table1"

    System.setProperty("user.name", "hdfs")
    System.setProperty("HADOOP_USER_NAME", "hdfs")
    conf.set("hbase.master", "localhost:60000")
    conf.setInt("timeout", 120000)
    conf.set("hbase.zookeeper.quorum", "localhost")
    conf.set("zookeeper.znode.parent", "/hbase-unsecure")
    conf.set(TableInputFormat.INPUT_TABLE, tableName)

    val admin = new HBaseAdmin(conf)
    if (!admin.isTableAvailable(tableName)) {
      val tableDesc = new HTableDescriptor(tableName)
      admin.createTable(tableDesc)
    }

    val hBaseRDD = sc.newAPIHadoopRDD(conf, classOf[TableInputFormat], classOf[ImmutableBytesWritable], classOf[Result])
    println("Number of Records found : " + hBaseRDD.count())
    sc.stop()
  }
}

Can anyone give me some hints how to find the correct dependencies, objects and stuff?

It seems like HBaseConfiguration is in hbase-client , but I actually stuck on TableInputFormat.INPUT_TABLE . Shouldn´t this be in the same dependency?

Is there a better way to access hbase with spark?

Answer 1

TableInputFormat class is in hbase-server.jar and you would need to add that dependency in your pom.xml. Please check HBase and non-existent TableInputFormat at Spark user list.

<dependency>
    <groupId>org.apache.hbase</groupId>
    <artifactId>hbase-server</artifactId>
    <version>1.3.0</version>
</dependency>

And below is the sample code to read from Hbase using Spark.

public static void main(String[] args) throws Exception {
    SparkConf sparkConf = new SparkConf().setAppName("HBaseRead").setMaster("local[*]");
    JavaSparkContext jsc = new JavaSparkContext(sparkConf);
    Configuration hbaseConf = HBaseConfiguration.create();
    hbaseConf.set(TableInputFormat.INPUT_TABLE, "my_table");
    JavaPairRDD<ImmutableBytesWritable, Result> javaPairRdd = jsc.newAPIHadoopRDD(hbaseConf, TableInputFormat.class,ImmutableBytesWritable.class, Result.class);
    jsc.stop();
  }
}

Answer 2

Yes. There is. Use SparkOnHbase from Cloudera.

<dependency>
    <groupId>org.apache.hbase</groupId>
    <artifactId>hbase-spark</artifactId>
    <version>1.2.0-cdh5.7.0</version>
</dependency>

And the use HBase scan to read data from you HBase table (or Bulk Get if you know the keys of the rows you want to retrieve).

Configuration conf = HBaseConfiguration.create();
conf.addResource(new Path("/etc/hbase/conf/core-site.xml"));
conf.addResource(new Path("/etc/hbase/conf/hbase-site.xml"));
JavaHBaseContext hbaseContext = new JavaHBaseContext(jsc, conf);

Scan scan = new Scan();
scan.setCaching(100);

JavaRDD<Tuple2<byte[], List<Tuple3<byte[], byte[], byte[]>>>> hbaseRdd = hbaseContext.hbaseRDD(tableName, scan);

System.out.println("Number of Records found : " + hBaseRDD.count())