求助：scala的json4s把JValue转为对象时报错 java.lang.NoSuchMethodError: scala.Predef$.$conforms()Lscala/Predef$$l

Posted 2021-01-23 dummyly

测试代码：
import org.json4s._
import org.json4s.JsonDSL._
import org.json4s.jackson.JsonMethods._
case class Winner(id: Long, numbers: List[Int])
object Test extends App{
  val winner = Winner(23, List(2, 45, 34, 23, 3, 5))
　 //Winner转json
  val json = ("id" -> winner.id) ~ ("numbers" -> winner.numbers)
  //json转String
  val str: String = compact(render(json))
  println(str)
  implicit val formats = DefaultFormats
  //String转json
  val jValue: JValue = parse(str)
  //json转Winner
  val winner2: Winner = jValue.extract[Winner]
  print(winner2)
}
报错：Exception in thread "main" java.lang.NoSuchMethodError: scala.Predef$.$conforms()Lscala/Predef$$less$colon$less;

spark是1.6.1，scala是2.10.5
porm.xml
<dependency>

    <groupId>org.apache.spark</groupId>
    <artifactId>spark-core_2.10</artifactId>
    <version>1.6.1</version>
</dependency>
<dependency>
    <groupId>org.apache.spark</groupId>
    <artifactId>spark-streaming_2.10</artifactId>
    <version>1.6.1</version>
</dependency>

<dependency>
    <groupId>org.apache.spark</groupId>
    <artifactId>spark-streaming-kafka_2.10</artifactId>
    <version>1.6.1</version>
</dependency>
<dependency>
    <groupId>org.scala-lang</groupId>
    <artifactId>scala-library</artifactId>
    <version>2.10.5</version>
</dependency>
<dependency>

    <groupId>org.json4s</groupId>
    <artifactId>json4s-jackson_2.10</artifactId>
    <version>3.5.3</version>
</dependency>
<dependency>
    <groupId>org.apache.kafka</groupId>
    <artifactId>kafka_2.10</artifactId>
    <version>0.8.2.1</version>
</dependency>
为什么一直报错，救助！？