【发布时间】：2020-10-01 20:35:10
【问题描述】：
Scala 新手，根据 README 顶部的第二个示例，我正在使用 https://github.com/embeddedkafka/embedded-kafka 实现 ScalaTest 的第一步：
import net.manub.embeddedkafka.EmbeddedKafka
import org.scalatest.matchers.should.Matchers
import org.scalatest.wordspec.AnyWordSpecLike
class MinimalTest extends AnyWordSpecLike with Matchers {
"runs with embedded kafka" should {
"work" in {
EmbeddedKafka.start()
1 + 1 shouldBe 2
// ... code goes here
EmbeddedKafka.stop()
}
}
}
运行这个测试，失败的级别比我熟悉的要低：
MinimalTest:
runs with embedded kafka
*** RUN ABORTED ***
java.lang.NoClassDefFoundError: scala/collection/GenTraversableOnce
at com.myorganization.api.MinimalTest.$anonfun$new$2(MinimalTest.scala:13)
at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18)
at org.scalatest.OutcomeOf.outcomeOf(OutcomeOf.scala:85)
at org.scalatest.OutcomeOf.outcomeOf$(OutcomeOf.scala:83)
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.wordspec.AnyWordSpecLike$$anon$3.apply(AnyWordSpecLike.scala:1076)
at org.scalatest.TestSuite.withFixture(TestSuite.scala:196)
at org.scalatest.TestSuite.withFixture$(TestSuite.scala:195)
...
Cause: java.lang.ClassNotFoundException: scala.collection.GenTraversableOnce
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
at com.myorganization.api.MinimalTest.$anonfun$new$2(MinimalTest.scala:13)
at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18)
at org.scalatest.OutcomeOf.outcomeOf(OutcomeOf.scala:85)
at org.scalatest.OutcomeOf.outcomeOf$(OutcomeOf.scala:83)
at org.scalatest.OutcomeOf$.outcomeOf(OutcomeOf.scala:104)
at org.scalatest.Transformer.apply(Transformer.scala:22)
at org.scalatest.Transformer.apply(Transformer.scala:20)
...
我怀疑依赖版本不匹配，但无法发现。这是我的相关 build.gradle 内容：
plugins {
id 'java'
id 'scala'
}
task spec(dependsOn: ['testClasses'], type: JavaExec) {
main = 'org.scalatest.tools.Runner'
args = ['-R', 'build/classes/scala/test', '-o']
classpath = sourceSets.test.runtimeClasspath
}
dependencies {
compile 'io.confluent:kafka-streams-avro-serde:5.4.0'
compile 'io.github.embeddedkafka:embedded-kafka-streams_2.12:2.4.0'
compile 'io.github.embeddedkafka:embedded-kafka_2.12:2.4.0'
compile 'org.apache.avro:avro:1.9.1'
compile 'org.apache.kafka:kafka-clients:2.4.0'
compile 'org.apache.kafka:kafka-streams:2.4.0'
compile 'org.apache.kafka:kafka_2.13:2.4.0'
compile 'org.scala-lang:scala-reflect:2.12.6'
testCompile 'io.github.embeddedkafka:embedded-kafka-schema-registry_2.12:5.4.0' // match schema registry version
testCompile 'io.github.embeddedkafka:embedded-kafka-streams_2.13:2.4.0' // match kafka streams version
testCompile 'io.github.embeddedkafka:embedded-kafka_2.13:2.4.0' // match kafka version
testCompile 'org.scala-lang:scala-library:2.13.2'
testCompile 'org.scalatest:scalatest_2.13:3.1.2'
testImplementation 'junit:junit:4.11'
testRuntime 'org.pegdown:pegdown:1.4.2'
}
【问题讨论】：
-
scala-reflect 2.13.2 而不是 2.12.6？另一件事是在您的测试用例中使用 scalatest 的 beforeandafterall
-
谢谢！大问题...
org.apache.kafka:kafka_2.13:2.4.0中的2.13代表 Scala 2.13。所以所有这些都需要更新为2.12
标签： java scala gradle apache-kafka scalatest