继承
【类的继承格式】
class 父类{}
class 子类 extends 父类 {}
例子:
package test; import java.util.jar.Attributes.Name; class Person { private String name; private int age; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } } class Student extends Person { } public class ExtDemo02 { public static void main(String args[]) { Student stu = new Student(); stu.setName("张三"); stu.setAge(30); System.out.println("姓名:" + stu.getName() + ",年龄:" + stu.getAge()); } }
结果:
姓名:张三,年龄:30
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student类继承了Person类,同时也集成了Person的属性age,name
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也可以通过子类扩展父类
例子:
package test; import java.util.jar.Attributes.Name; class Person { private String name; private int age; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } } class Student extends Person { private String school; public String getschool(){ return school; } public void setSchool(String school){ this.school=school; } } public class ExtDemo02 { public static void main(String args[]) { Student stu = new Student(); stu.setName("张三"); stu.setAge(30); stu.setSchool("家里蹲大学"); System.out.println("姓名:" + stu.getName() + ",年龄:" + stu.getAge()+",学校:"+stu.getschool()); } }
结果:
姓名:张三,年龄:30,学校:家里蹲大学
此例子扩展了父类。
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注意:
1.java中只允许单继承,即一个儿子只能有一个爹,一个爹可以有多个儿子
2.允许多层继承
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子类要访问父类的私有方法、属性。不能直接调用,要通过getter和setter来实现
待续.......