前言

Github:https://github.com/HealerJean

博客:http://blog.healerjean.com

Type是Class的父接口。

Class是Type的子类。

instanceof

instanceof操作符用于判断一个引用类型所引用的对象是否是一个类的实例。

  public  void instanceOf(Object object) {

        /**
         *  ==
         */
        if(Long.class == object.getClass()){
            System.out.println("Long.class == object.getClass()");
        }

        /**
         * equals
         */
        if(Long.class.equals(object.getClass()) ){
            System.out.println("Long.class.equals(object.getClass()) ");
        }

        /**
         * instance Of
         */
        if(object instanceof  Long){
            System.out.println("object instanceof  Long");
        }
    } 

== 和 equals比较的实际的Class类,没有考虑继承,instanceof 和 isInstance考虑继承


 
class  Father{}
class  Son extends  Father{}


public void fatherAndSon(){
    Father son = new Son(); //和 Son son = new Son(); 一样
    Father father = new Father();

    //son.getClass() ==  father.getClass() :false
    System.out.println("son.getClass() ==  father.getClass() :" +(son.getClass() == father.getClass()) );

    //son.getClass().equals(father.getClass()) :false
    System.out.println("son.getClass().equals(father.getClass()) :" +(son.getClass().equals(father.getClass())) );

    //son  instanceof Father :true
    System.out.println("son  instanceof Father :" +(son  instanceof Father ));

    //father  instanceof Son :false   //父类不能  instanceof  子类
    System.out.println("father  instanceof Son :" +(father  instanceof Son ));

    //father  instanceof Father :true
    System.out.println("father  instanceof Father :" +(father  instanceof Father ));

    //son.getClass().isInstance(father):false  //子类不能 isInstance 父亲
  System.out.println("son.getClass().isInstance(father):"+son.getClass().isInstance(father));

    //father.getClass().isInstance(son):true
  System.out.println("father.getClass().isInstance(son):"+father.getClass().isInstance(son));

    //son.getClass().isInstance(son)true
  System.out.println("son.getClass().isInstance(son)"+son.getClass().isInstance(son));

}

@Test
public void testFatherAndSon(){
    fatherAndSon();
}



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