0016.scala中的包

本文介绍了Scala中的包管理方式,包括包对象的定义与使用、类的继承与方法覆盖等特性,并展示了如何在不同场景下引入和使用包。

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package com.jn.scala

/**
* Created by admin on 2015/11/13.
*/
//包对象
package com.scala.spark
package object people{//包对象中可以定义变量,定义方法,
 
val defaultName = "Scala"
}
package people{//包中定义包对象,包中所有类都可以使用在包对象中定义的变量与方法
 
class People{
   
val name = defaultName
 
}
}

package spark.navigation{
 
abstract class Navigator{
   
def act
  }
 
package test{
   
class NavigatorSuite
  }
 
package impls{
   
class Action extends Navigator{
     
override def act =println( "Action")
    }
  }
}
package hadoop{
 
package navigation{
   
class Navigator
  }
 
package launch{

 
import com.jn.scala.hadoop.navigation.Navigator

 
class Booster{
     
val nav = new Navigator
    }
  }
}
object PackagesOps {

}

Scala中包的隐式引用
import java.lang._//java.lang包是所有内容
import scala._//scala包的所有内容
import Predef._//Predef包的所有内容


import java.awt.{Color,Font}//指定引入包下面的内容
import java.util{HashMap => JavaHashMap}//起别名,防止java与scal冲突
import scala.{StringBuilder => _}//不引入某个类
Error:scalac: Error: Error compiling the sbt component 'compiler-interface-2.10.0-52.0' sbt.internal.inc.CompileFailed: Error compiling the sbt component 'compiler-interface-2.10.0-52.0' at sbt.internal.inc.AnalyzingCompiler$.handleCompilationError$1(AnalyzingCompiler.scala:331) at sbt.internal.inc.AnalyzingCompiler$.$anonfun$compileSources$4(AnalyzingCompiler.scala:346) at sbt.internal.inc.AnalyzingCompiler$.$anonfun$compileSources$4$adapted(AnalyzingCompiler.scala:341) at sbt.io.IO$.withTemporaryDirectory(IO.scala:376) at sbt.io.IO$.withTemporaryDirectory(IO.scala:383) at sbt.internal.inc.AnalyzingCompiler$.$anonfun$compileSources$2(AnalyzingCompiler.scala:341) at sbt.internal.inc.AnalyzingCompiler$.$anonfun$compileSources$2$adapted(AnalyzingCompiler.scala:335) at sbt.io.IO$.withTemporaryDirectory(IO.scala:376) at sbt.io.IO$.withTemporaryDirectory(IO.scala:383) at sbt.internal.inc.AnalyzingCompiler$.compileSources(AnalyzingCompiler.scala:335) at org.jetbrains.jps.incremental.scala.local.CompilerFactoryImpl$.org$jetbrains$jps$incremental$scala$local$CompilerFactoryImpl$$getOrCompileInterfaceJar(CompilerFactoryImpl.scala:123) at org.jetbrains.jps.incremental.scala.local.CompilerFactoryImpl.$anonfun$getScalac$1(CompilerFactoryImpl.scala:55) at scala.Option.map(Option.scala:163) at org.jetbrains.jps.incremental.scala.local.CompilerFactoryImpl.getScalac(CompilerFactoryImpl.scala:47) at org.jetbrains.jps.incremental.scala.local.CompilerFactoryImpl.createCompiler(CompilerFactoryImpl.scala:25) at org.jetbrains.jps.incremental.scala.local.CachingFactory.$anonfun$createCompiler$3(CachingFactory.scala:24) at org.jetbrains.jps.incremental.scala.local.Cache.$anonfun$getOrUpdate$2(Cache.scala:20) at scala.Option.getOrElse(Option.scala:138) at org.jetbrains.jps.incremental.scala.local.Cache.getOrUpdate(Cache.scala:19) at org.jetbrains.jps.incremental.scala.local.CachingFactory.createCompiler(CachingFactory.scala:24) at org.jetbrains.jps.incremental.scala.local.LocalServer.compile(LocalServer.scala:34) at org.jetbrains.jps.incremental.scala.remote.Main$.compileLogic(Main.scala:117) at org.jetbrains.jps.incremental.scala.remote.Main$.handleCommand(Main.scala:109) at org.jetbrains.jps.incremental.scala.remote.Main$.serverLogic(Main.scala:95) at org.jetbrains.jps.incremental.scala.remote.Main$.nailMain(Main.scala:53) at org.jetbrains.jps.incremental.scala.remote.Main.nailMain(Main.scala) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at com.martiansoftware.nailgun.NGSession.run(NGSession.java:319)
最新发布
08-15
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