java入門第二季--繼承--Object類

molyzzx 發(fā)布于2019-08-16 14:42 / 3529人閱讀

摘要：類方法代碼類執(zhí)行了重寫方法右鍵類執(zhí)行了兩個(gè)對(duì)象是相等的兩個(gè)對(duì)象是不相等的重寫右鍵年齡狗可以吃東西類執(zhí)行了兩個(gè)對(duì)象是相等的兩個(gè)對(duì)象是不相等的

Object類

toString()方法

代碼

/javaDemo3/src/com/imooc/Animal.java

package com.imooc;

public class Animal {
    public Animal() {

    }
}

/javaDemo3/src/com/imooc/Dog.java

package com.imooc;
import java.util.*;
public class Dog extends Animal {

    public Dog() {
        System.out.println("Dog類執(zhí)行了" );
    }

}

/javaDemo3/src/com/imooc/Initail.java

package com.imooc;

public class Initail {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Dog dog = new Dog();
        System.out.println(dog);
    }

}

重寫toString()方法

/javaDemo3/src/com/imooc/Dog.java
右鍵 -> source -> genenor toString
]

package com.imooc;
import java.util.*;
public class Dog extends Animal {

    public Dog() {
        System.out.println("Dog類執(zhí)行了" );
    }

    public String toString() {
        return "Dog [age=" + age + "]";
    }

}

equals

/javaDemo3/src/com/imooc/Initail.java

package com.imooc;

public class Initail {

    public static void main(String[] args) {
        Dog dog = new Dog();
        Dog dog2 = new Dog();
        if(dog.equals(dog2)) {
            System.out.println("兩個(gè)對(duì)象是相等的");
        }else {
            System.out.println("兩個(gè)對(duì)象是不相等的");
        }
    }

}

重寫equals
右鍵-> source-> generate->hascode equals

/javaDemo3/src/com/imooc/Dog.java

package com.imooc;
import java.util.*;
public class Dog extends Animal {
    public int age = 20;
    public void eat() {
        System.out.println("年齡:"+age+ "狗可以吃東西" );
    }
    public Dog() {
        System.out.println("Dog類執(zhí)行了" );
    }
    public void method() {
        System.out.println(age);
        System.out.println("super" + super.age);
        eat();
        super.eat();
    }
    public String toString() {
        return "Dog [age=" + age + "]";
    }

    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Dog other = (Dog) obj;
        if (age != other.age)
            return false;
        return true;
    }

}

/javaDemo3/src/com/imooc/Initail.java

package com.imooc;

public class Initail {

    public static void main(String[] args) {

        Dog dog = new Dog();
        Dog dog2 = new Dog();


        if(dog.equals(dog2)) {
            System.out.println("兩個(gè)對(duì)象是相等的");
        }else {
            System.out.println("兩個(gè)對(duì)象是不相等的");
        }
    }

}