|NO.Z.00029|——————————|BigDataEnd|——|Hadoop&Scala.V02|——|Scala.v02|类与对象|自定义getter|setter方法|

一、自定义getter和setter方法

### --- 自定义getter和setter方法
~~~     对于 Scala 类中的每一个属性，编译后会有一个私有的字段和相应的getter、setter方法生成。

~~~     getter方法
println(person age)
~~~     setter方法
person age_= (18)
~~~     getter方法
println(person.age)

### --- 可以不使用自动生成的方式，自己定义getter和setter方法

class Dog {
    private var _leg = 0
//自定义getter方法
def leg = _leg
//自定义setter方法
def leg_=(newLeg: Int) {
    _leg = newLeg
}
}
// 使用自定义getter和setter方法
val dog = new Dog
dog.leg_=(4)
println(dog.leg)

### --- 自定义变量的getter和setter方法需要遵循以下原则：

~~~     字段属性名以“_”作为前缀，如： _leg
~~~     getter方法定义为：def leg = _leg
~~~     setter方法定义为：def leg_=(newLeg: Int)

二、编程实现getter和setter方法

### --- 编程代码

package yanqi.cn.part04

class Dog {
  private var _leg = 0

  //自定义getter方法
  def leg: Int = _leg

  //自定义的setter方法
  def leg_=(newLeg: Int): Unit = {
    _leg = newLeg
  }
}

object GetterAndSetterDemo {
  def main(args: Array[String]): Unit = {
    val dog = new Dog
    //调用自定义的setter方法
    dog.leg_=(4)
    //调用自定义的getter方法
    println(dog.leg)
  }
}

### --- 编译打印

D:\JAVA\jdk1.8.0_231\bin\java.exe "-javaagent:D:\IntelliJIDEA\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=55479:D:\IntelliJIDEA\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath D:\JAVA\jdk1.8.0_231\jre\lib\charsets.jar;D:\JAVA\jdk1.8.0_231\jre\lib\deploy.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\access-bridge-64.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\cldrdata.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\dnsns.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\jaccess.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\jfxrt.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\localedata.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\nashorn.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\sunec.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\sunjce_provider.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\sunmscapi.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\sunpkcs11.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\zipfs.jar;D:\JAVA\jdk1.8.0_231\jre\lib\javaws.jar;D:\JAVA\jdk1.8.0_231\jre\lib\jce.jar;D:\JAVA\jdk1.8.0_231\jre\lib\jfr.jar;D:\JAVA\jdk1.8.0_231\jre\lib\jfxswt.jar;D:\JAVA\jdk1.8.0_231\jre\lib\jsse.jar;D:\JAVA\jdk1.8.0_231\jre\lib\management-agent.jar;D:\JAVA\jdk1.8.0_231\jre\lib\plugin.jar;D:\JAVA\jdk1.8.0_231\jre\lib\resources.jar;D:\JAVA\jdk1.8.0_231\jre\lib\rt.jar;E:\NO.Z.10000——javaproject\NO.Z.00002.Hadoop\ScalaPro\out\production\ScalaPro;D:\JAVA\scala-2.12.2\lib\scala-library.jar;D:\JAVA\scala-2.12.2\lib\scala-reflect.jar yanqi.cn.part04.GetterAndSetterDemo
4

Process finished with exit code 0

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Walter Savage Landor:strove with none,for none was worth my strife.Nature I loved and, next to Nature, Art:I warm'd both hands before the fire of life.It sinks, and I am ready to depart

                                                                                                                                                   ——W.S.Landor

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