Question

JAVA 问题：为什么 程序最后的三句 会输出 如下的结果？？？求解释

程序
public class PersonProject {

public static void main(String[] args) {

Person p1;

Person p2;

Person p3;

p1 = new Person("Chris", "M", "SIP");

p2 = new Person("Fred", "M", "Shanghai");

p3 = new Person("Gloria", "F", "Beijing");
System.out.println("Objects in class Person:");
System.out.println(p1.toString());
System.out.println(p2.toString());
System.out.println(p3.toString());

} }

OUT PUT
Objects in class Person:

Person [name=Chris, gender=M, address=SIP, idNumber=1] Person [name=Fred, gender=M, address=Shanghai, idNumber=2] Person [name=Gloria, gender=F, address=Beijing, idNumber=3]

Answer 1

你所调用的Person类是否有私有变量，构造方法是如何定义的，还有这个类应该是复写了toString方法，一看就很好理解了

Answer 2

Person类重载了toString方法
例如
@Override
public String toString()
{
return "Person [name="+this.name+","....;//这里自己按格式写

}