如何使用Spark/Scala读取Hbase的数据

必须使用高亮参数启动Spark-shell,否则当你遍历RDD时会出现如下的Exception

java.io.NotSerializableException: org.apache.hadoop.hbase.io.ImmutableBytesWritable

 

spark-shell --conf spark.serializer=org.apache.spark.serializer.KryoSerializer

 

以下代码,经过MaprDB实测通过

import org.apache.spark._
import org.apache.spark.rdd.NewHadoopRDD
import org.apache.hadoop.hbase.{HBaseConfiguration, HTableDescriptor}
import org.apache.hadoop.hbase.client.HBaseAdmin
import org.apache.hadoop.hbase.mapreduce.TableInputFormat
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HColumnDescriptor
import org.apache.hadoop.hbase.util.Bytes
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.HTable;


val tableName = "/app/SubscriptionBillingPlatform/TRANSAC_ID"

val conf = HBaseConfiguration.create()

conf.set(TableInputFormat.INPUT_TABLE, tableName)


//create rdd
val hBaseRDD = sc.newAPIHadoopRDD(conf, classOf[TableInputFormat], 
  classOf[org.apache.hadoop.hbase.io.ImmutableBytesWritable],
  classOf[org.apache.hadoop.hbase.client.Result])


hBaseRDD.take(2).map(row=>row._2.rawCells). 
                 map(_.map( kv => (new String(kv.getQualifier()) -> new String(kv.getValue()) ) ).toMap ).
                 foreach( map => { map.foreach{ entry => print(entry._1 +":" + entry._2 + ", ")  } ; print("\n-----------\n") }  )  
                 
//get the row count
val count = hBaseRDD.count()
print("HBase RDD count:"+count)