object

1
class Person{
2
    private String name;
3
    private int age;
4
    public Person(String name , int age){
5
        this.name = name;
6
        this.age = age;
7
    }
8
    @Override
9
    public String toString(){
10
        return "name:"+this.name+"age:"+this.age;
11
    }
12
}
13

14
public class duotai{
15
    public static void main(String args []){
4 collapsed lines
16
        Person per = new Person("dog", 18);
17
        System.out.println(per);        // 默认调用toStirng方法，覆写Object中的toString方法
18
    }
19
}

1
class Person{
2
    private String name;
3
    private int age;
4
    public Person(String name , int age){
5
        this.name = name;
6
        this.age = age;
7
    }
8
    public boolean equals(Object obj){
9
        if(!(obj instanceof Person)){    // 如果不是同类，则直接返回false，不同类无法比较
10
            return false;
11
        }
12
        if(obj == null){    //如果不判断null会报空指针错误
13
        return false;
14
        }
15
        if(this == obj)    {    // 如果是自己跟自己比，则比较地址
15 collapsed lines
16
            return true;
17
        }
18

19
        Person per = (Person) obj;
20
        return this.name.equals(per.name) && this.age == per.age;
21
    }
22
}
23

24
public class duotai{
25
    public static void main(String args []){
26
        Person per1 = new Person("寮犱笁", 18);
27
        Person per2 = new Person("寮犱笁", 18);
28
        System.out.println(per1.equals(per2));    // true
29
    }
30
}