Java equals方法的应用场景和重写

import java.util.Objects;

public class Demo62 {

    public static void main(String[] args) {
        String s = "helloWorld";
        String s1 = "hello";
        String s2 = "World";
        String s3 = s1 + s2;
        Animal a = new Animal(s);
        Animal b = new Animal(s);
        System.out.println(a.equals(b));//默认先比较地址
//        public boolean equals(Object obj) {
//            return (this == obj);
//        }
        System.out.println(Objects.equals(a.name,b.name));//比较的是值
        System.out.println(s.equals(s3));//相同的常量池之间的比较

    }

    public static class Animal{
        String name;

        public Animal(String name) {
            this.name = name;
        }
        @Override
        public boolean equals(Object obj) {//重写equals
            if (obj == this) {//相同的地址直接返回true
                return true;
            }

            if (!(obj instanceof Animal)) {//不同的类直接返回false
                return false;
            }

            Animal other = (Animal) obj//不同的地址但是相同的类则比较属性值
            return Objects.equals(name, other.name);
        }
    }
}