instanceof

package java1;
public class Application {
    public static void main(String[] argc){
        //Object>Person>Student
        Object object=new Student();
System.out.println(object instanceof Student);//t
System.out.println(object instanceof Person);//t
System.out.println(object instanceof Object);//t
System.out.println(object instanceof Teacher);//f
System.out.println(object instanceof String);//f
System.out.println("===========");
Person person=new Student();
        System.out.println(person instanceof Student);//t
        System.out.println(person instanceof Person);//t
        System.out.println(person instanceof Object);//t
        System.out.println(person instanceof Teacher);//f
        //System.out.println(person instanceof String);编译报错
        System.out.println("===========");
       Student student=new Student();
        System.out.println(student instanceof Student);//t
        System.out.println(student instanceof Person);//t
        System.out.println(student instanceof Object);//t
       // System.out.println(student instanceof Teacher);
      //  System.out.println(student instanceof String);
    }
}

package java1;
public class Person {
    public void run(){
        System.out.println("run");
    }
}

package java1;
public class Person {
    public void run(){
        System.out.println("run");
    }
}

package java1;
public class Student extends Person{
    public void go(){
        System.out.println("go");
    }
}

package java1;
public class Application {
    public static void main(String[] argc){
//类型之间的转换：父   子
//子类转换为父类，可能丢失自己的本来的一些方法！
        Student student=new Student();
        Student.go();
        Person person=Student;
    }
}