Java:关于对象的概念

Question

    public class ex11_2 {
    public static void main(String[] args){
        Object a=new Person("abc1","def1","ghi1");
        System.out.println(a.toString());
        Object b=new Person("abc2","def2","ghi2");

        System.out.println(a.toString());
    }
}

class Person{
    private static String name;
    private static String address;
    private static String phoneNo;

    public Person(){
    }

    public Person(String name,String address,String phoneNo){
        setName(name);
        setAddress(address);
        setPhoneNo(phoneNo);
    }

    public String toString(){
        return super.toString()+(" "+getName()+","+getAddress()+","+getPhoneNo()+".");
    }

    public static String getName() {
        return Person.name;
    }

    public static void setName(String name) {
        Person.name = name;
    }

    public static String getAddress() {
        return address;
    }

    public static void setAddress(String address) {
        Person.address = address;
    }

    public static String getPhoneNo() {
        return phoneNo;
    }

    public static void setPhoneNo(String phoneNo) {
        Person.phoneNo = phoneNo;
    }
}

各位大家好.我是Java编程的初学者,想在OOP上提问.在这个小程序中,我创建了一个Person类并测试其toString()方法.

测试结果如下:

Person@635b9e68 abc1,def1,ghi1.
Person@635b9e68 abc2,def2,ghi2.

我想知道为什么b的数据字段将在创建b之后替换a的数据字段.谢谢

Answer 1

您的成员变量是静态的,不会附加到该类的任何实例.

private static String name;
private static String address;
private static String phoneNo;

静态成员将在该类的实例中可用.要更正它,请将它们更改为非静态成员变量.

private String name;
private String address;
private String phoneNo;