爲什麼它運行的應用程序

Question

時拋出的RuntimeException當我運行命令：

d：\ scalaTest> FSC Summer.scala ChecksumAccumulator.scala

d：\ scalaTest>斯卡拉大的hello world

的例外是：

Exception in thread "main" java.lang.RuntimeException: Cannot figure out how to run target: Summer 
     at scala.sys.package$.error(package.scala:27) 
     at scala.tools.nsc.GenericRunnerCommand.scala$tools$nsc$GenericRunnerCommand$$guessHowToRun(GenericRunnerCommand.scala:38) 
     at scala.tools.nsc.GenericRunnerCommand$$anonfun$2.apply(GenericRunnerCommand.scala:48) 
     at scala.tools.nsc.GenericRunnerCommand$$anonfun$2.apply(GenericRunnerCommand.scala:48) 
     at scala.Option.getOrElse(Option.scala:108) 
     at scala.tools.nsc.GenericRunnerCommand.<init>(GenericRunnerCommand.scala:48) 
     at scala.tools.nsc.GenericRunnerCommand.<init>(GenericRunnerCommand.scala:17) 
     at scala.tools.nsc.MainGenericRunner.process(MainGenericRunner.scala:33) 
     at scala.tools.nsc.MainGenericRunner$.main(MainGenericRunner.scala:89) 
     at scala.tools.nsc.MainGenericRunner.main(MainGenericRunner.scala) 

這是在源代碼中cludeing 2個階文件：

一個是Summer.scala：

import ChecksumAccumulator.calculate 

object Summer { 
    def main(args:Array[String]) { 
    for(arg <- args) 
     println(arg + ":" + calculate(arg)) 
    } 
} 

另一個是ChecksumAccumulator.scala：

import scala.collection.mutable.Map 

class ChecksumAccumulator { 

    private var sum=0 

    def add(b:Byte) { sum += b } 

    def checksum():Int = ~(sum & 0xFF) + 1 
} 

object ChecksumAccumulator { 

    private val cache = Map[String,Int]() 

    def calculate(s:String):Int = 
    if(cache.contains(s)) 
     cache(s) 
    else { 
     val acc = new ChecksumAccumulator 
     for(c<-s) 
     acc.add(c.toByte) 
     val cs = acc.checksum() 
     cache += (s->cs) 
     cs 
    } 
} 

非常感謝

順便說一句：這是Martin Odersky編寫的書「Scala 2nd.Edition編程」中的例子

Answer 1

如果我不得不猜測，這是因爲您的CLASSPATH環境變量不包括.。

只要被正確生成您的Summer.class文件，你應該能夠得到它與

scala -cp . Summer hello world