8.18 获取对象信息 toString()方法

demo1 toString

class Person {}

public class HelloWorld {
    public static void main(String args[]){
        Person per = new Person();
        System.out.println(per);
        System.out.println(per.toString());// Object类继承而来;

    }

}

Person@2a139a55
Person@2a139a55

demo2 输出类，默认调取的是toString() 方法

class Person {
    private String name;
    private int age;
    public Person(String name,int age){
        this.name = name;
        this.age = age;
    }

    @Override
    public String toString(){
        return "姓名:" + this.name + ",年龄:" + this.age;
    }
}


public class HelloWorld {
    public static void main(String args[]){
        Person per = new Person("张三",22);
        System.out.println(per);// 输出类，默认调取toString方法;
    }
}