SparkSession在akka中的多线程同步的情况

sparkSession：

 /** * The entry point to programming Spark with the Dataset and DataFrame API. * * In environments that this has been created upfront (e.g. REPL, notebooks), use the builder * to get an existing session: * * {{{ *   SparkSession.builder().getOrCreate() * }}} * * The builder can also be used to create a new session: * * {{{ *   SparkSession.builder *     .master("local") *     .appName("Word Count") *     .config("spark.some.config.option", "some-value") *     .getOrCreate() * }}} * * @param sparkContext The Spark context associated with this Spark session. * @param existingSharedState If supplied, use the existing shared state *                            instead of creating a new one. * @param parentSessionState If supplied, inherit all session state (i.e. temporary *                            views, SQL config, UDFs etc) from parent. */@InterfaceStability.Stableclass SparkSession private(    @transient val sparkContext: SparkContext,    @transient private val existingSharedState: Option[SharedState],    @transient private val parentSessionState: Option[SessionState],    @transient private[sql] val extensions: SparkSessionExtensions)  extends Serializable with Closeable with Logging { self =>  private[sql] def this(sc: SparkContext) {    this(sc, None, None, new SparkSessionExtensions)  }  sparkContext.assertNotStopped()  // If there is no active SparkSession, uses the default SQL conf. Otherwise, use the session's.  SQLConf.setSQLConfGetter(() => {    SparkSession.getActiveSession.map(_.sessionState.conf).getOrElse(SQLConf.getFallbackConf)  })  ……

package com.ljt.spark01.sql

import org.apache.spark.SparkConf
import org.apache.spark.sql.SparkSession

import com.ljt.spark01.sql.TestActor.Bean
import com.ljt.spark01.sql.TestActor.CreateView

import akka.actor.Actor
import akka.actor.ActorLogging
import scala.util.Random
import org.apache.spark.SparkConf
import akka.actor.ActorSystem
import akka.actor.Props
import org.apache.spark.SparkConf

/**
* ljt
* 我的服务端的逻辑是在actor内部进行的，但发现多个actor中执行的过程中，访问到了其他actor内部session中注册的临时表
*
*/
class TestActor(sparkConf: SparkConf) extends Actor with ActorLogging {
var sparkSession: SparkSession = _
override def preStart(): Unit = {
sparkSession=getSparkSession(sparkConf)
}

def getSparkSession(sparkConf: SparkConf) = SparkSession.synchronized {
SparkSession.clearDefaultSession()
val session = SparkSession.builder().config(sparkConf).getOrCreate()
SparkSession.clearDefaultSession()
session
}

override def postStop(): Unit = sparkSession.stop()
override def receive: Receive = {
case CreateView(limit) ⇒ sparkSession.createDataFrame(getBeans(limit)).createOrReplaceTempView(“test1”)
case s: String ⇒
log.info(s”exec $s”)
sparkSession.sql(s).show(1000)
case e: Any ⇒ println(e)
}

val ids = 1 to 1000
val names = (‘a’ to ‘z’).map(_.toString())

val beans = for {
id <- ids
name <- names
} yield Bean(id, name)

def getBeans(limit: Int): Seq[Bean] = {

Random.shuffle(beans).take(limit)

}

}

//伴生对象
object TestActor {

case class CreateView(limit: Int)
case class Bean(id: Int, name: String)
}
/**
* 测试驱动类
*/
object test {
def main(args: Array[String]): Unit = {
val saprkConf = new SparkConf().setAppName(“testActor”).setMaster(“local[*]”)
val actorSystem = ActorSystem(“testackkaSystem”)
val props = Props(new TestActor(saprkConf))
val actor1 = actorSystem.actorOf(props, name = “actor01”)
val actor2 = actorSystem.actorOf(props, name = “actor02”)
val actor3 = actorSystem.actorOf(props, name = “actor03”)
val actor4 = actorSystem.actorOf(props, name = “actor04”)
val actor5 = actorSystem.actorOf(props, name = “actor05”)
/**
* 答疑：参考http://blog.csdn.net/wust__wangfan/article/details/50911023
* Null和Nil
* Null是所有AnyRef的子类，在scala的类型系统中，AnyRef是Any的子类，同时Any子类的还有AnyVal。对应java值类型的所有类型都是AnyVal的子类。所以Null可以赋值给所有的引用类型(AnyRef)，不能赋值给值类型，这个java的语义是相同的。
* null是Null的唯一对象
* Nil是一个空的List，定义为List[Nothing]，根据List的定义List[+A]，所有Nil是所有List[T]的子类。
*/
val actors = actor1 :: actor2 :: actor3 :: actor4 :: actor5 :: Nil
def getLimit = Random.nextInt(100)
actors.foreach { x => x ! CreateView(getLimit) }
Thread sleep 1000
// actors.foreach(_ ! “select * from test1”)
actors.foreach { x => x ! “show tables” }
Thread sleep 1000

actors.foreach { x => x ! "select * from test1" }Thread sleep 1000

}
}