[英]What import is missing to make Spark's MLlib linear regression in Scala example work?
[英]What to import to make < work for jodatime in Scala
我想比較LocalDateTime,但最終出現異常。
我有這些課:
import org.scala_tools.time.Imports._
import org.scala_tools.time.Implicits._
case class Event(id: String, startDate: LocalDateTime, action: String)
case class Events(events: List[Event], timeout: Int) {
val timeoutDt: LocalDateTime = new LocalDateTime().minusMinutes(timeout)
lazy val oldEvents = events.filter { (e: Event) =>
e.startDate < timeoutDt
}
lazy val eventsToSend = events.filterNot { (e: Event) =>
e.startDate < timeoutDt
}
}
我有這個例外:
scala> import org.scala_tools.time.Imports._
scala> import org.scala_tools.time.Implicits._
scala> val d1 = new LocalDateTime("2010-11-17T10:10:10")
d1: org.joda.time.LocalDateTime = 2010-11-17T10:10:10.000
scala> val d2 = new LocalDateTime("2012-11-17T10:10:10")
d2: org.joda.time.LocalDateTime = 2012-11-17T10:10:10.000
scala> val e1 = new Event("a", d1, "a")
scala> val e2 = new Event("b", d2, "b")
scala> val es = Events(List(e1, e2), 10000)
scala> val old = es.oldEvents
java.lang.NoClassDefFoundError: scala/Ordered
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:634)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:277)
at java.net.URLClassLoader.access$000(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:212)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
at scala.tools.nsc.util.ScalaClassLoader$URLClassLoader.scala$tools$nsc$util$ScalaClassLoader$$super$findClass(ScalaClassLoader.scala:86)
at scala.tools.nsc.util.ScalaClassLoader$class.findClass(ScalaClassLoader.scala:51)
at scala.tools.nsc.util...
我忘記了什么?
=======編輯============
我正在使用Scala 2.8.0。 感謝@Alex,我發現project/build/Project.scala
文件中的依賴項不正確:
import java.io.File
import sbt._
class Project(info: ProjectInfo) extends DefaultProject(info) {
// ... omitted code
// OBS: Must have this to access snapshots
val snap = ScalaToolsSnapshots
// Time
lazy val jodaTime = "joda-time" % "joda-time" % "1.6"
lazy val scalaTime = "org.scala-tools" % "time" % "2.8.0-SNAPSHOT-0.2-SNAPSHOT" // Does not work
}
〜
以下代碼有效:
import java.io.File
import sbt._
class Project(info: ProjectInfo) extends DefaultProject(info) {
// ... omitted code
// Time
lazy val jodaTime = "joda-time" % "joda-time" % "1.6"
lazy val scalaTime = "org.scala-tools.time" % "time_2.8.0" % "0.2"
}
仍然不確定為什么快照不起作用。
java.lang.NoClassDefFoundError: scala/Ordered
意味着您有Scala版本不匹配或類路徑問題。
您正在使用的庫很可能沒有針對當前的Scala版本進行編譯。
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