如何在火花壳内使用nscala_time

Question

我正在尝试在火花外壳中测试一些代码，我需要设置一些时间字段。我们正在使用nscala_time实现日期时间功能。当我跑步时

$ scala -cp `ls -1 | tr "\n" ":"`

从带有我的暂存 jar 的目录中，一切正常，我可以运行

scala> import com.github.nscala_time.time.Imports._
import com.github.nscala_time.time.Imports._
scala> val current = DateTime.now
current: org.joda.time.DateTime = 2015-04-23T10:44:35.984-07:00

但是当我在 spark-shell 1.3.0 上尝试同样的事情时

$ spark-shell -cp `ls -1 | tr "\n" ":"

我最终在执行与scala控制台相同的操作时遇到错误

scala> import com.github.nscala_time.time.Imports._
import com.github.nscala_time.time.Imports._
scala> val current = DateTime.now
java.lang.NoSuchMethodError: scala.Predef$.$conforms()Lscala/Predef$$less$colon$less;
    at com.github.nscala_time.time.LowPriorityOrderingImplicits$class.ReadableInstantOrdering(Implicits.scala:64)
    at com.github.nscala_time.time.Imports$.ReadableInstantOrdering(Imports.scala:20)
    at com.github.nscala_time.time.OrderingImplicits$class.$init$(Implicits.scala:56)
    at com.github.nscala_time.time.Imports$.<init>(Imports.scala:20)
    at com.github.nscala_time.time.Imports$.<clinit>(Imports.scala)
    at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:22)
    at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:27)
    at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:29)
    at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:31)
    at $iwC$$iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:33)
    at $iwC$$iwC$$iwC$$iwC$$iwC.<init>(<console>:35)
    at $iwC$$iwC$$iwC$$iwC.<init>(<console>:37)
    at $iwC$$iwC$$iwC.<init>(<console>:39)
    at $iwC$$iwC.<init>(<console>:41)
    at $iwC.<init>(<console>:43)
    at <init>(<console>:45)
    at .<init>(<console>:49)
    at .<clinit>(<console>)
    at .<init>(<console>:7)
    at .<clinit>(<console>)
    at $print(<console>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.spark.repl.SparkIMain$ReadEvalPrint.call(SparkIMain.scala:1065)
    at org.apache.spark.repl.SparkIMain$Request.loadAndRun(SparkIMain.scala:1338)
    at org.apache.spark.repl.SparkIMain.loadAndRunReq$1(SparkIMain.scala:840)
    at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:871)
    at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:819)
    at org.apache.spark.repl.SparkILoop.reallyInterpret$1(SparkILoop.scala:856)
    at org.apache.spark.repl.SparkILoop.interpretStartingWith(SparkILoop.scala:901)
    at org.apache.spark.repl.SparkILoop.command(SparkILoop.scala:813)
    at org.apache.spark.repl.SparkILoop.processLine$1(SparkILoop.scala:656)
    at org.apache.spark.repl.SparkILoop.innerLoop$1(SparkILoop.scala:664)
    at org.apache.spark.repl.SparkILoop.org$apache$spark$repl$SparkILoop$$loop(SparkILoop.scala:669)
    at org.apache.spark.repl.SparkILoop$$anonfun$org$apache$spark$repl$SparkILoop$$process$1.apply$mcZ$sp(SparkILoop.scala:996)
    at org.apache.spark.repl.SparkILoop$$anonfun$org$apache$spark$repl$SparkILoop$$process$1.apply(SparkILoop.scala:944)
    at org.apache.spark.repl.SparkILoop$$anonfun$org$apache$spark$repl$SparkILoop$$process$1.apply(SparkILoop.scala:944)
    at scala.tools.nsc.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:135)
    at org.apache.spark.repl.SparkILoop.org$apache$spark$repl$SparkILoop$$process(SparkILoop.scala:944)
    at org.apache.spark.repl.SparkILoop.process(SparkILoop.scala:1058)
    at org.apache.spark.repl.Main$.main(Main.scala:31)
    at org.apache.spark.repl.Main.main(Main.scala)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:569)
    at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:166)
    at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:189)
    at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:110)
    at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)

有人知道为什么我不能在火花外壳中使用nscala_time吗？

Answer 1

我使用 spark 1.3.0，它有更好的错误输出。它告诉我：

scala.reflect.internal.Types$TypeError：错误的符号引用。一个 BuilderImplicits中的签名.class是指术语时间值 org.joda 不可用。

所以，我下载了丢失的org.joda jar并用它运行火花：

~  spark-shell --jars nscala-time_2.10-0.2.0.jar,joda-time-2.7.jar
...
scala> import com.github.nscala_time.time.Imports._
import com.github.nscala_time.time.Imports._
scala> val current = DateTime.now
current: org.joda.time.DateTime = 2015-04-23T22:35:50.344+03:00

我的另一个猜测是您应该尝试在粘贴模式下运行代码（scala>:paste）。堆栈跟踪看起来非常接近问题。也许问题出在火花壳本身。