SparkSql_UDF_UDAF_Mysql_Hive

文章目录

• ​​1.UDF​​
• ​​2.UDAF​​
• ​​3.Mysql数据源​​
• ​​4.Hive​​

1.UDF

object Spark03 {
  def main(args: Array[String]): Unit = {
    val sparkConf = new SparkConf().setAppName("Sql").setMaster("local")
    val spark = SparkSession.builder().config(sparkConf).getOrCreate()
    val df = spark.read.json("data/input.json")
    df.createOrReplaceTempView("user")
    // TODO
    // UDF
    spark.udf.register("prefixName", (name: String) => {
        "Name" + name
    })
    spark.sql("select name, prefixName(age) from user").show()
    spark.close()
  }


}
      

2.UDAF

1.弱类型函数实现

UserDefinedAggregateFunction 抽象类

object Spark04_UDAF {
  def main(args: Array[String]): Unit = {
    val sparkConf = new SparkConf().setMaster("local").setAppName("Sql")
    val spark = SparkSession.builder().config(sparkConf).getOrCreate()

    val df = spark.read.json("data/input.json")
    df.createOrReplaceTempView("user")

    spark.udf.register("avgAge", new MyAvgUDAF())

    spark.sql("select avgAge(age) from user").show()
    spark.close()
  }
  // 弱类型函数实现
  class MyAvgUDAF extends UserDefinedAggregateFunction{
    override def inputSchema: StructType = {
      StructType(
        Array(
          StructField("age", LongType)
        )
      )
    }

    override def bufferSchema: StructType = {
      StructType(
        Array(
          StructField("total", LongType),
          StructField("count", LongType)
        )
      )
    }
    // 输出
    override def dataType: DataType = LongType
    // 函数稳定性
    override def deterministic: Boolean = true
    // 缓冲区初始化
    override def initialize(buffer: MutableAggregationBuffer): Unit = {
      buffer.update(0, 0L)
      buffer.update(1, 0L)

    }

    override def update(buffer: MutableAggregationBuffer, input: Row): Unit = {
      buffer.update(0, buffer.getLong(0) + input.getLong(0))
      buffer.update(1, buffer.getLong(1) + 1)
    }

    override def merge(buffer1: MutableAggregationBuffer, buffer2: Row): Unit = {
      buffer1.update(0, buffer1.getLong(0) + buffer2.getLong(0))
      buffer1.update(1, buffer1.getLong(1) + buffer2.getLong(1))
    }
    // 计算
    override def evaluate(buffer: Row): Any = {
      buffer.getLong(0)/buffer.getLong(1)
    }
  }

}
      

2.强类型函数实现

Aggregator 抽象类

object Spark05_UDAF {
  def main(args: Array[String]): Unit = {
    val sparkConf = new SparkConf().setMaster("local").setAppName("Sql")
    val spark = SparkSession.builder().config(sparkConf).getOrCreate()
    val df = spark.read.json("data/input.json")
    df.createOrReplaceTempView("user")
    // 强转弱
    spark.udf.register("avgAge", functions.udaf(new MyAvgUDAF1))
    spark.sql("select avgAge(age) from user").show()

    spark.close()
  }
  case class Buff(var total:Long, var count: Long)
  class MyAvgUDAF1 extends Aggregator[Long, Buff, Long]{
    override def zero: Buff = {
      Buff(0L, 0L)
    }

    override def reduce(b: Buff, a: Long): Buff = {
      b.total = b.total + a
      b.count = b.count + 1
      b
    }

    override def merge(b1: Buff, b2: Buff): Buff = {
      b1.total = b1.total + b2.total
      b1.count = b1.count + b2.count
      b1
    }

    override def finish(reduction: Buff): Long = {
      reduction.total / reduction.count
    }
    // 缓冲区的编码
    override def bufferEncoder: Encoder[Buff] = Encoders.product
    // 输入的编码
    override def outputEncoder: Encoder[Long] = Encoders.scalaLong
  }

}
      

3.Mysql数据源

object Spark06 {
  def main(args: Array[String]): Unit = {
    // spark.read.format("json").load
    // df.write.format("json").save()
    // Mysql

    val sparkConf = new SparkConf().setMaster("local").setAppName("Sql")
    val spark = SparkSession.builder().config(sparkConf).getOrCreate()
    import spark.implicits._

    val df = spark.read.format("jdbc")
      .option("url", "jdbc:mysql:///test")
      .option("driver", "com.mysql.jdbc.Driver")
      .option("user", "root")
      .option("password", "root")
      .option("dbtable", "user9")
      .load()
    df.show()

    df.write.format("jdbc")
      .option("url", "jdbc:mysql:///test")
      .option("driver", "com.mysql.jdbc.Driver")
      .option("user", "root")
      .option("password", "root")
      .option("dbtable", "user8")
      .mode(SaveMode.Append)
        .save()


    spark.close()
  }

}
      

4.Hive

maven

mysql
            mysql-connector-java
            5.1.27
        

        
            org.apache.spark
            spark-hive_2.12
            3.0.0
        
      

object Spark07_Hive {
  def main(args: Array[String]): Unit = {
    val sparkConf = new SparkConf().setMaster("local").setAppName("Sql")
    val spark = SparkSession.builder().enableHiveSupport().config(sparkConf).getOrCreate()
    import spark.implicits._
    spark.sql("show tables").show()
    spark.close()
  }

}