|--需求说明

要求通过毛色，名字，品种来判定两条狗是不是同一条狗

|--实现方法

通过重写equals方法，对比毛色，名字，品种，这几个属性一致，则判定是同一条狗

|--代码内容

 1 public class Dog {
 2     private String name;
 3     private String color;
 4     private String breed;
 5 
 6     public Dog() {
 7     }
 8 
 9     public Dog(String name, String color, String breed) {
10         this.name = name;
11         this.color = color;
12         this.breed = breed;
13     }
14 
15     @Override
16     public boolean equals(Object obj) {
17         if (this == obj) {
18             return true;
19         }
20         if (!(obj instanceof Dog)) {
21             return false;
22         }
23         Dog dog = (Dog)obj;
24         if (this.name.equals(dog.name)&&this.breed.equals(dog.breed)&&this.color.equals(dog.color)){
25             return true;
26         }else {
27             return false;
28         }
29     }
30 }

Dog类

 1 public class DogTest {
 2     public static void main(String[] args) {
 3         Dog dog1 = new Dog("小黄", "白色", "中华田园犬");
 4         Dog dog2 = new Dog("小黄", "白色", "中华田园犬");
 5 
 6         if (dog1.equals(dog2)) {
 7             System.out.println("这两只狗是同一只狗");
 8         } else {
 9             System.out.println("这两只狗不是同一只狗");
10         }
11     }
12 }

测试Dog类

|--运行效果

 

|--将重写equails的部分注销掉之后的运行结果

 

|--将Dog类重新增加注释发出来

 1 public class Dog {
 2     private String name;
 3     private String color;
 4     private String breed;
 5 //无参构造方法
 6     public Dog() {
 7     }
 8 //带参构造方法
 9     public Dog(String name, String color, String breed) {
10         this.name = name;
11         this.color = color;
12         this.breed = breed;
13     }
14 //重写equails方法
15     @Override
16     public boolean equals(Object obj) {
17         //如果传入的对象和对象本身一致，则判定是同一只
18         if (this == obj) {
19             return true;
20         }
21         //如果对象不属于Dog类，则判定不是同一类
22         if (!(obj instanceof Dog)) {
23             return false;
24         }
25         //将传入类转化为Dog类
26         Dog dog = (Dog)obj;
27         //给出比对条件，比较name，breed，color三个属性，三个属性一致，则是同一条狗
28         if (this.name.equals(dog.name)&&this.breed.equals(dog.breed)&&this.color.equals(dog.color)){
29             return true;
30         }else {
31             return false;
32         }
33     }
34 }