(废话扯一波)我们知道定一个person类,包括了string name,int age 等,有了这个类以后,我们如果想定义一个student类,如果没有现在的知识点,我们是不是又得重新去定义一个学生类中的name age呢?这是不是十分冗余呢?所以继承性诞生了,少说废话,进正题吧!
讲到这里,你也差不多明白了子父类的关系了。那我们顺便说一下一个特别重要的东西
那我们想要掉用父类中的方法呢?这就要提到我们的关键字super了
class Person {
String name = "张三";
protected int age;
public String getInfo() {
return "Name: " + name + "\nage: " + age; } }
class Student extends Person {
protected String name = "李四";
private String school = "New Oriental";
public String getSchool() {
return school; }
public String getInfo() {
return super.getInfo() + "\nschool: " + school;
}
}
public class text {
public static void main(String[] args) {
Student st = new Student();
System.out.println(st.getInfo());
}}
public class Person {
private String name;
private int age;
private Date birthDate;
public Person(String name, int age, Date d) {
this.name = name;
this.age = age;
this.birthDate = d; }
public Person(String name, int age) {
this(name, age, null);
}
public Person(String name, Date d) {
this(name, 30, d);
}
public Person(String name) {
this(name, 30);
} }
class Student extends Person {
private String school;
public Student(String name, int age, String s) {
super(name, age);
school = s; }
public Student(String name, String s) {
super(name);
school = s; }
// 编译出错: no super(),系统将调用父类无参数的构造器。
public Student(String s) {
school = s; } }
class person{
int age;
public preson(int age)
{
this.age=age;
}
}
class student extends person
{
String name;
public student(String nameString)//报错!!!
{
this.name=nameString;
}
}
因篇幅问题不能全部显示,请点此查看更多更全内容
Copyright © 2019- huatuo0.cn 版权所有 湘ICP备2023017654号-2
违法及侵权请联系:TEL:199 1889 7713 E-MAIL:2724546146@qq.com
本站由北京市万商天勤律师事务所王兴未律师提供法律服务