卡桑德拉單位與斯卡拉。不會話

Question

我想用cassandraunit測試Cassandra。我從github粘貼測試並轉換爲Scala，但它不起作用。

import org.junit.Rule 
import org.scalatest.FunSuite 
import com.datastax.driver.core.ResultSet 
import org.cassandraunit.CassandraCQLUnit 
import org.cassandraunit.dataset.cql.ClassPathCQLDataSet 

class CassandraTest extends FunSuite{ 

    @Rule 
    val cassandraCQLUnit = new CassandraCQLUnit(new ClassPathCQLDataSet("statementsWithBlankEndings.cql", "mykeyspace")) 

    test("really simple transformation") { 

     val session = cassandraCQLUnit.session 
     val resultSet = session.execute("select * from testCQLTable WHERE id='1690e8da-5bf8-49e8-9583-4dff8a570737'") 
     println(resultSet.iterator().next().getString("value")) 

    } 
} 


java.lang.NullPointerException was thrown. 
java.lang.NullPointerException 
    at CassandraTest$$anonfun$1.apply$mcV$sp(CassandraTest.scala:21) 
    at CassandraTest$$anonfun$1.apply(CassandraTest.scala:18) 
    at CassandraTest$$anonfun$1.apply(CassandraTest.scala:18) 
    at org.scalatest.OutcomeOf$class.outcomeOf(OutcomeOf.scala:85) 
    at org.scalatest.OutcomeOf$.outcomeOf(OutcomeOf.scala:104) 
    at org.scalatest.Transformer.apply(Transformer.scala:22) 
    at org.scalatest.Transformer.apply(Transformer.scala:20) 
    at org.scalatest.FunSuiteLike$$anon$1.apply(FunSuiteLike.scala:186) 
    at org.scalatest.TestSuite$class.withFixture(TestSuite.scala:196) 
    at org.scalatest.FunSuite.withFixture(FunSuite.scala:1560) 
    at org.scalatest.FunSuiteLike$class.invokeWithFixture$1(FunSuiteLike.scala:183) 
    at org.scalatest.FunSuiteLike$$anonfun$runTest$1.apply(FunSuiteLike.scala:196) 
    at org.scalatest.FunSuiteLike$$anonfun$runTest$1.apply(FunSuiteLike.scala:196) 
    at org.scalatest.SuperEngine.runTestImpl(Engine.scala:289) 
    at org.scalatest.FunSuiteLike$class.runTest(FunSuiteLike.scala:196) 
    at org.scalatest.FunSuite.runTest(FunSuite.scala:1560) 
    at org.scalatest.FunSuiteLike$$anonfun$runTests$1.apply(FunSuiteLike.scala:229) 
    at org.scalatest.FunSuiteLike$$anonfun$runTests$1.apply(FunSuiteLike.scala:229) 
    at org.scalatest.SuperEngine$$anonfun$traverseSubNodes$1$1.apply(Engine.scala:396) 
    at org.scalatest.SuperEngine$$anonfun$traverseSubNodes$1$1.apply(Engine.scala:384) 
    at scala.collection.immutable.List.foreach(List.scala:381) 
    at org.scalatest.SuperEngine.traverseSubNodes$1(Engine.scala:384) 
    at org.scalatest.SuperEngine.org$scalatest$SuperEngine$$runTestsInBranch(Engine.scala:379) 
    at org.scalatest.SuperEngine.runTestsImpl(Engine.scala:461) 
    at org.scalatest.FunSuiteLike$class.runTests(FunSuiteLike.scala:229) 
    at org.scalatest.FunSuite.runTests(FunSuite.scala:1560) 
    at org.scalatest.Suite$class.run(Suite.scala:1147) 
    at org.scalatest.FunSuite.org$scalatest$FunSuiteLike$$super$run(FunSuite.scala:1560) 
    at org.scalatest.FunSuiteLike$$anonfun$run$1.apply(FunSuiteLike.scala:233) 
    at org.scalatest.FunSuiteLike$$anonfun$run$1.apply(FunSuiteLike.scala:233) 
    at org.scalatest.SuperEngine.runImpl(Engine.scala:521) 
    at org.scalatest.FunSuiteLike$class.run(FunSuiteLike.scala:233) 
    at org.scalatest.FunSuite.run(FunSuite.scala:1560) 
    at org.scalatest.tools.SuiteRunner.run(SuiteRunner.scala:45) 
    at org.scalatest.tools.Runner$$anonfun$doRunRunRunDaDoRunRun$1.apply(Runner.scala:1340) 
    at org.scalatest.tools.Runner$$anonfun$doRunRunRunDaDoRunRun$1.apply(Runner.scala:1334) 
    at scala.collection.immutable.List.foreach(List.scala:381) 
    at org.scalatest.tools.Runner$.doRunRunRunDaDoRunRun(Runner.scala:1334) 
    at org.scalatest.tools.Runner$$anonfun$runOptionallyWithPassFailReporter$2.apply(Runner.scala:1011) 
    at org.scalatest.tools.Runner$$anonfun$runOptionallyWithPassFailReporter$2.apply(Runner.scala:1010) 
    at org.scalatest.tools.Runner$.withClassLoaderAndDispatchReporter(Runner.scala:1500) 
    at org.scalatest.tools.Runner$.runOptionallyWithPassFailReporter(Runner.scala:1010) 
    at org.scalatest.tools.Runner$.run(Runner.scala:850) 
    at org.scalatest.tools.Runner.run(Runner.scala) 
    at org.jetbrains.plugins.scala.testingSupport.scalaTest.ScalaTestRunner.runScalaTest2(ScalaTestRunner.java:138) 
    at org.jetbrains.plugins.scala.testingSupport.scalaTest.ScalaTestRunner.main(ScalaTestRunner.java:28) 

Session變量爲空，我不知道爲什麼。我瞭解cassandraCQLUnit在同一個VM中有一個Cassandra服務器。是否有必要做別的事情？

Answer 1

您需要啓動服務器並連接。然後你可以加載數據：

import com.datastax.driver.core.{Cluster, Session} 
import org.cassandraunit.CQLDataLoader 
import org.cassandraunit.dataset.cql.ClassPathCQLDataSet 
import org.cassandraunit.utils.EmbeddedCassandraServerHelper 
import org.scalatest.{BeforeAndAfterAll, FunSuite} 

class CassandraTest extends FunSuite 
    with BeforeAndAfterAll { 

    var cluster : Cluster = _ 
    var session : Session = _ 

    override def beforeAll(): Unit = { 
    EmbeddedCassandraServerHelper.startEmbeddedCassandra(EmbeddedCassandraServerHelper.CASSANDRA_RNDPORT_YML_FILE) 
    cluster = EmbeddedCassandraServerHelper.getCluster() 
    session = cluster.connect() 

    val dataLoader = new CQLDataLoader(session) 
    dataLoader.load(new ClassPathCQLDataSet("statementsWithBlankEndings.cql","mykeyspace")) 
    } 

    test("really simple transformation") { 

    val resultSet = session.execute("select * from mykeyspace.testCQLTable WHERE id='1690e8da-5bf8-49e8-9583-4dff8a570737'") 
    println(resultSet.iterator().next().getString("value")) 

    } 

}