learning scala Case Classses

package com.aura.scala.day01

object caseClasses {
  def main(args: Array[String]): Unit = {
    // 注意在实例化案例类时，并没有使用关键字new, 这是因为案例类有一个默认的apply
    // 方法来负责对象的创建。
    val frankenstein = Book("978-0486282114")
    println(frankenstein.isbn)
    val message1 = Message("panzidong", "lianghong", "come on")
    println(message1.body,message1.recipient,message1.sender)
    // 案例类的比较是按值而非按引用比较

    val message2 = Message("panzidong", "lianghong", "come on")
    val message3 = Message("panzidong", "lianghong", "come on")
    println(message2 == message3)
    // 案例类的拷贝

    val message4 = Message("panzidong", "lianghong", "come on")
    val message5 = message4.copy(sender = message4.recipient, recipient = "")
    println(message5.sender, message5.recipient, message5.body)

  }
  case class Book(isbn: String)
  case class Message(sender: String, recipient: String,body: String)
}

resule:

"D:\Program Files\Java\jdk1.8.0_201\bin\java.exe" "-javaagent:D:\Program Files\JetBrains\IntelliJ IDEA 2019.1.3\lib\idea_rt.jar=5581:D:\Program Files\JetBrains\IntelliJ IDEA 2019.1.3\bin" -Dfile.encoding=UTF- -classpath "D:\Program Files\Java\jdk1.8.0_201\jre\lib\charsets.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\deploy.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\access-bridge-64.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\cldrdata.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\dnsns.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\jaccess.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\jfxrt.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\localedata.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\nashorn.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\sunec.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\sunjce_provider.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\sunmscapi.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\sunpkcs11.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\ext\zipfs.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\javaws.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\jce.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\jfr.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\jfxswt.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\jsse.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\management-agent.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\plugin.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\resources.jar;D:\Program Files\Java\jdk1.8.0_201\jre\lib\rt.jar;C:\Users\admin\IdeaProjects\ScalaDay\out\production\ScalaDay;C:\Program Files (x86)\scala\lib\scala-actors-2.11.0.jar;C:\Program Files (x86)\scala\lib\scala-actors-migration_2.11-1.1.0.jar;C:\Program Files (x86)\scala\lib\scala-library.jar;C:\Program Files (x86)\scala\lib\scala-parser-combinators_2.11-1.0.4.jar;C:\Program Files (x86)\scala\lib\scala-reflect.jar;C:\Program Files (x86)\scala\lib\scala-swing_2.11-1.0.2.jar;C:\Program Files (x86)\scala\lib\scala-xml_2.11-1.0.4.jar" com.aura.scala.day01.caseClasses
-
(come on,lianghong,panzidong)
true
(lianghong,,come on)

Process finished with exit code