1. HBase读写的方式概况

主要分为：

1. 纯Java API读写HBase的方式；
2. Spark读写HBase的方式；
3. Flink读写HBase的方式；
4. HBase通过Phoenix读写的方式；

第一种方式是HBase自身提供的比较原始的高效操作方式，而第二、第三则分别是Spark、Flink集成HBase的方式，最后一种是第三方插件Phoenix集成的JDBC方式，Phoenix集成的JDBC操作方式也能在Spark、Flink中调用。

注意：

这里我们使用HBase2.1.2版本，spark2.4版本，scala-2.12版本，以下代码都是基于该版本开发的。

2. Spark上读写HBase

 Spark上读写HBase主要分为新旧两种API，另外还有批量插入HBase的，通过Phoenix操作HBase的。

2.1 spark读写HBase的新旧API

2.1.1 spark写数据到HBase

使用旧版本saveAsHadoopDataset保存数据到HBase上。

/**
 * saveAsHadoopDataset
 */
def writeToHBase(): Unit ={
  // 屏蔽不必要的日志显示在终端上
  Logger.getLogger("org.apache.spark").setLevel(Level.WARN)

  /* spark2.0以前的写法
  val conf = new SparkConf().setAppName("SparkToHBase").setMaster("local")
  val sc = new SparkContext(conf)
  */
  val sparkSession = SparkSession.builder().appName("SparkToHBase").master("local[4]").getOrCreate()
  val sc = sparkSession.sparkContext

  val tableName = "test"

  //创建HBase配置
  val hbaseConf = HBaseConfiguration.create()
  hbaseConf.set(HConstants.ZOOKEEPER_QUORUM, "192.168.187.201") //设置zookeeper集群，也可以通过将hbase-site.xml导入classpath，但是建议在程序里这样设置
  hbaseConf.set(HConstants.ZOOKEEPER_CLIENT_PORT, "2181") //设置zookeeper连接端口，默认2181
  hbaseConf.set(TableOutputFormat.OUTPUT_TABLE, tableName)

  //初始化job，设置输出格式，TableOutputFormat 是 org.apache.hadoop.hbase.mapred 包下的
  val jobConf = new JobConf(hbaseConf)
  jobConf.setOutputFormat(classOf[TableOutputFormat])

  val dataRDD = sc.makeRDD(Array("12,jack,16", "11,Lucy,15", "15,mike,17", "13,Lily,14"))

  val data = dataRDD.map{ item =>
      val Array(key, name, age) = item.split(",")
      val rowKey = key.reverse
      val put = new Put(Bytes.toBytes(rowKey))
      /*一个Put对象就是一行记录，在构造方法中指定主键
       * 所有插入的数据 须用 org.apache.hadoop.hbase.util.Bytes.toBytes 转换
       * Put.addColumn 方法接收三个参数：列族，列名，数据*/
      put.addColumn(Bytes.toBytes("cf1"), Bytes.toBytes("name"), Bytes.toBytes(name))
      put.addColumn(Bytes.toBytes("cf1"), Bytes.toBytes("age"), Bytes.toBytes(age))
      (new ImmutableBytesWritable(), put)
  }
  //保存到HBase表
  data.saveAsHadoopDataset(jobConf)
  sparkSession.stop()
}

 使用新版本saveAsNewAPIHadoopDataset保存数据到HBase上

a.txt文件内容为：

100,hello,20
101,nice,24
102,beautiful,26

/**
 * saveAsNewAPIHadoopDataset
 */
 def writeToHBaseNewAPI(): Unit ={
   // 屏蔽不必要的日志显示在终端上
   Logger.getLogger("org.apache.spark").setLevel(Level.WARN)
   val sparkSession = SparkSession.builder().appName("SparkToHBase").master("local[4]").getOrCreate()
   val sc = sparkSession.sparkContext

   val tableName = "test"
   val hbaseConf = HBaseConfiguration.create()
   hbaseConf.set(HConstants.ZOOKEEPER_QUORUM, "192.168.187.201")
   hbaseConf.set(HConstants.ZOOKEEPER_CLIENT_PORT, "2181")
   hbaseConf.set(org.apache.hadoop.hbase.mapreduce.TableOutputFormat.OUTPUT_TABLE, tableName)

   val jobConf = new JobConf(hbaseConf)
   //设置job的输出格式
   val job = Job.getInstance(jobConf)
   job.setOutputKeyClass(classOf[ImmutableBytesWritable])
   job.setOutputValueClass(classOf[Result])
   job.setOutputFormatClass(classOf[org.apache.hadoop.hbase.mapreduce.TableOutputFormat[ImmutableBytesWritable]])

   val input = sc.textFile("v2120/a.txt")

   val data = input.map{item =>
   val Array(key, name, age) = item.split(",")
   val rowKey = key.reverse
   val put = new Put(Bytes.toBytes(rowKey))
   put.addColumn(Bytes.toBytes("cf1"), Bytes.toBytes("name"), Bytes.toBytes(name))
   put.addColumn(Bytes.toBytes("cf1"), Bytes.toBytes("age"), Bytes.toBytes(age))
   (new ImmutableBytesWritable, put)
   }
   //保存到HBase表
   data.saveAsNewAPIHadoopDataset(job.getConfiguration)
   sparkSession.stop()
}

2.1.2 spark从HBase读取数据

使用newAPIHadoopRDD从hbase中读取数据，可以通过scan过滤数据

/**
 * scan
 */
 def readFromHBaseWithHBaseNewAPIScan(): Unit ={
   //屏蔽不必要的日志显示在终端上
   Logger.getLogger("org.apache.spark").setLevel(Level.WARN)
   val sparkSession = SparkSession.builder().appName("SparkToHBase").master("local").getOrCreate()
   val sc = sparkSession.sparkContext

   val tableName = "test"
   val hbaseConf = HBaseConfiguration.create()
   hbaseConf.set(HConstants.ZOOKEEPER_QUORUM, "192.168.187.201")
   hbaseConf.set(HConstants.ZOOKEEPER_CLIENT_PORT, "2181")
   hbaseConf.set(org.apache.hadoop.hbase.mapreduce.TableInputFormat.INPUT_TABLE, tableName)

   val scan = new Scan()
   scan.addFamily(Bytes.toBytes("cf1"))
   val proto = ProtobufUtil.toScan(scan)
   val scanToString = new String(Base64.getEncoder.encode(proto.toByteArray))
   hbaseConf.set(org.apache.hadoop.hbase.mapreduce.TableInputFormat.SCAN, scanToString)

   //读取数据并转化成rdd TableInputFormat是org.apache.hadoop.hbase.mapreduce包下的
   val hbaseRDD = sc.newAPIHadoopRDD(hbaseConf, classOf[org.apache.hadoop.hbase.mapreduce.TableInputFormat], classOf[ImmutableBytesWritable], classOf[Result])

   val dataRDD = hbaseRDD
     .map(x => x._2)
     .map{result =>
       (result.getRow, result.getValue(Bytes.toBytes("cf1"), Bytes.toBytes("name")), result.getValue(Bytes.toBytes("cf1"), Bytes.toBytes("age")))
     }.map(row => (new String(row._1), new String(row._2), new String(row._3)))
     .collect()
     .foreach(r => (println("rowKey:"+r._1 + ", name:" + r._2 + ", age:" + r._3)))
}

2.2 spark利用BulkLoad往HBase批量插入数据

BulkLoad原理是先利用mapreduce在hdfs上生成相应的HFlie文件，然后再把HFile文件导入到HBase中，以此来达到高效批量插入数据。

/**
 * 批量插入 多列
 */
 def insertWithBulkLoadWithMulti(): Unit ={

   val sparkSession = SparkSession.builder().appName("insertWithBulkLoad").master("local[4]").getOrCreate()
   val sc = sparkSession.sparkContext

   val tableName = "test"
   val hbaseConf = HBaseConfiguration.create()
   hbaseConf.set(HConstants.ZOOKEEPER_QUORUM, "192.168.187.201")
   hbaseConf.set(HConstants.ZOOKEEPER_CLIENT_PORT, "2181")
   hbaseConf.set(TableOutputFormat.OUTPUT_TABLE, tableName)

   val conn = ConnectionFactory.createConnection(hbaseConf)
   val admin = conn.getAdmin
   val table = conn.getTable(TableName.valueOf(tableName))

   val job = Job.getInstance(hbaseConf)
   //设置job的输出格式
   job.setMapOutputKeyClass(classOf[ImmutableBytesWritable])
   job.setMapOutputValueClass(classOf[KeyValue])
   job.setOutputFormatClass(classOf[HFileOutputFormat2])
   HFileOutputFormat2.configureIncrementalLoad(job, table, conn.getRegionLocator(TableName.valueOf(tableName)))

   val rdd = sc.textFile("v2120/a.txt")
     .map(_.split(","))
     .map(x => (DigestUtils.md5Hex(x(0)).substring(0, 3) + x(0), x(1), x(2)))
     .sortBy(_._1)
     .flatMap(x =>
       {
         val listBuffer = new ListBuffer[(ImmutableBytesWritable, KeyValue)]
         val kv1: KeyValue = new KeyValue(Bytes.toBytes(x._1), Bytes.toBytes("cf1"), Bytes.toBytes("name"), Bytes.toBytes(x._2 + ""))
         val kv2: KeyValue = new KeyValue(Bytes.toBytes(x._1), Bytes.toBytes("cf1"), Bytes.toBytes("age"), Bytes.toBytes(x._3 + ""))
         listBuffer.append((new ImmutableBytesWritable, kv2))
         listBuffer.append((new ImmutableBytesWritable, kv1))
         listBuffer
       }
     )
   //多列的排序，要按照列名字母表大小来
   
   isFileExist("hdfs://node1:9000/test", sc)

   rdd.saveAsNewAPIHadoopFile("hdfs://node1:9000/test", classOf[ImmutableBytesWritable], classOf[KeyValue], classOf[HFileOutputFormat2], job.getConfiguration)
   val bulkLoader = new LoadIncrementalHFiles(hbaseConf)
   bulkLoader.doBulkLoad(new Path("hdfs://node1:9000/test"), admin, table, conn.getRegionLocator(TableName.valueOf(tableName)))
}

/**
 * 判断hdfs上文件是否存在，存在则删除
 */
def isFileExist(filePath: String, sc: SparkContext): Unit ={
  val output = new Path(filePath)
  val hdfs = FileSystem.get(new URI(filePath), new Configuration)
  if (hdfs.exists(output)){
    hdfs.delete(output, true)
  }
}

2.3 spark利用Phoenix往HBase读写数据

利用Phoenix，就如同msyql等关系型数据库的写法，需要写jdbc

def readFromHBaseWithPhoenix: Unit ={
   //屏蔽不必要的日志显示在终端上
   Logger.getLogger("org.apache.spark").setLevel(Level.WARN)

   val sparkSession = SparkSession.builder().appName("SparkHBaseDataFrame").master("local[4]").getOrCreate()

   //表小写，需要加双引号，否则报错
   val dbTable = "\"test\""

   //spark 读取 phoenix 返回 DataFrame的第一种方式
   val rdf = sparkSession.read
     .format("jdbc")
     .option("driver", "org.apache.phoenix.jdbc.PhoenixDriver")
     .option("url", "jdbc:phoenix:192.168.187.201:2181")
     .option("dbtable", dbTable)
     .load()

   val rdfList = rdf.collect()
   for (i <- rdfList){
     println(i.getString(0) + " " + i.getString(1) + " " + i.getString(2))
   }
   rdf.printSchema()

   //spark 读取 phoenix 返回 DataFrame的第二种方式
   val df = sparkSession.read
     .format("org.apache.phoenix.spark")
     .options(Map("table" -> dbTable, "zkUrl" -> "192.168.187.201:2181"))
     .load()
   df.printSchema()
   val dfList = df.collect()
   for (i <- dfList){
      println(i.getString(0) + " " + i.getString(1) + " " + i.getString(2))
   }
   //spark DataFrame 写入 phoenix，需要先建好表
   /*df.write
     .format("org.apache.phoenix.spark")
     .mode(SaveMode.Overwrite)
     .options(Map("table" -> "PHOENIXTESTCOPY", "zkUrl" -> "jdbc:phoenix:192.168.187.201:2181"))
     .save()
*/
   sparkSession.stop()
}

3. 总结

HBase连接的几种方式（一）java篇 可以查看纯Java API读写HBase

HBase读写的几种方式（三）flink篇 可以查看flink读写HBase

github地址：

https://github.com/SwordfallYeung/HBaseDemo

参考资料：

https://my.oschina.net/uchihamadara/blog/2032481

https://www.cnblogs.com/simple-focus/p/6879971.html

https://www.cnblogs.com/MOBIN/p/5559575.html

https://blog.csdn.net/Suubyy/article/details/80892023

https://www.jianshu.com/p/b09283b14d84

https://www.jianshu.com/p/8e3fdf70dc06

https://www.cnblogs.com/wumingcong/p/6044038.html

https://blog.csdn.net/zhuyu_deng/article/details/43192271

https://www.jianshu.com/p/4c908e419b60

https://blog.csdn.net/Colton_Null/article/details/83387995