Kotlin中Object关键字的使用示例介绍

object AppConfig {
    //初始化代码块，对象初始化时调用。
    init {
        println("app config init ...")
    }
}
fun main() {
    val app1 = AppConfig
    val app2 = AppConfig
    println(app1)
    println(app2)
}

public final class AppConfig {
   @NotNull
   public static final AppConfig INSTANCE;
   private AppConfig() {
   }
   static {
      AppConfig var0 = new AppConfig();
      INSTANCE = var0;
      String var1 = "app config init ...";
      System.out.println(var1);
   }
}
 public static final void main() {
      AppConfig app1 = AppConfig.INSTANCE;
      AppConfig app2 = AppConfig.INSTANCE;
      System.out.println(app1);
      System.out.println(app2);
   }

fun main() {
    val p = object :Person("LiLei"){
        override fun doWork() {
            println("$name,is writing code...")
        }
    }
    p.doWork()
}

//父类必须用open修饰，才能够被继承
open class Person(val name: String) {
    //伴生对象，
    companion object {
        var idCard = ""
        //当创建类实例时，会自动调用伴生对象的init代码块
        init {
            idCard = "XXX"
            println("companion init")
        }
        fun getId(): String {
            return idCard
        }
    }
}

fun main() {
    //创建类实例是，会调用伴生对象的init代码块
    val p = Person
    //可以通过类实例，访问伴生对象定义的属性和方法
    println(p.idCard)
    println( p.getId())
}