什么是Java多態(tài)的向上轉(zhuǎn)型？具體實(shí)例代碼展示

class Animal {
    public String name;
    public void eat() {
        System.out.println(this.name + " 正在吃");
    }
}
class Cat extends Animal {
    
}
public class Test extends TestDemo {
 
    public static void main(String[] args) {
        //父類引用 引用了 子類引用所引用的對象
        Cat cat = new Cat();
        Animal animal = cat;//向上轉(zhuǎn)型
    }
}

package com.my.pac14;

/**
 * @auther Summerday
 */
public class DynamicBinding {
    //Object是所有類的超類，根據(jù)向上轉(zhuǎn)型，該方法可以接受任何類型的對象
    public static void test(Object x) {
        System.out.println(x.toString());
    }

    public static void main(String[] args) {
        test(new PrimaryStudent());//Student
        test(new Student());//Student
        test(new Person());//Person
        test(new Object());//java.lang.Object@1b6d3586
    }
}

class Person extends Object {
    @Override
    public String toString() {
        return "Person";
    }
}

class Student extends Person {
    @Override
    public String toString() {
        return "Student";
    }
}

class PrimaryStudent extends Student {
}