面向对象之继承

关于继承的理解，先看两个类

person类

class Person{
	private String name ;
	private int age ;
	public void setName(String name){
		this.name = name ;
	}
	public void setAge(int age){
		this.age = age ;
	}
	public String getName(){
		return this.name ;
	}
	public int getAge(){
		return this.age ;
	}
};

class Student{
	private String name ;
	private int age ;
	private String school ;
	public void setName(String name){
		this.name = name ;
	}
	public void setAge(int age){
		this.age = age ;
	}
	public void setSchool(String school){
		this.school = school ;
	}
	public String getName(){
		return this.name ;
	}
	public int getAge(){
		return this.age ;
	}
	public String getSchool(){
		return this.school ;
	}
};

一个简单的继承举例：

class Person{
	private String name ;
	private int age ;
	public void setName(String name){
		this.name = name ;
	}
	public void setAge(int age){
		this.age = age ;
	}
	public String getName(){
		return this.name ;
	}
	public int getAge(){
		return this.age ;
	}
};
class Student extends Person {
	private String school ;	// 扩充的属性
	public void setSchool(String school){
		this.school = school ;
	}
	public String getSchool(){
		return this.school ;
	}
};
public class ExtDemo03{
	public static void main(String args[]){
		Student stu = new Student() ;	//  学生
		stu.setName("张三") ;	// 从Person继承而来
		stu.setAge(30) ;		// 从Person继承而来
		stu.setSchool("西安电大") ;		// 自己定义的方法
		System.out.println("姓名：" + stu.getName()) ;
		System.out.println("年龄：" + stu.getAge()) ;
		System.out.println("学校：" + stu.getSchool()) ;
	}
};

java不允许一个类同时继承多个父类，但允许多层继承，此外子类不能直接访问父类的私有操作。

在子类实例化对象时，因为父类的构造优先于子类构造进行初始化，所以子类实例化操作中一般隐藏了super()方法，但也可以通过super()方法明确调用父类构造。

class Person{
	private String name ;
	private int age ;
	public Person(String name,int age){
		this.name = name ;
		this.age = age ;
	}
	public void setName(String name){
		this.name = name ;
	}
	public void setAge(int age){
		this.age = age ;
	}
	public String getName(){
		return this.name ;
	}
	public int getAge(){
		return this.age ;
	}
};
class Student extends Person {
	private String school ;	// 扩充的属性
	public Student(String name,int age,String school){
		super(name,age) ;	// 明确调用父类中有两个参数的构造方法
		this.school = school ;
	}
	public void setSchool(String school){
		this.school = school ;
	}
	public String getSchool(){
		return this.school ;
	}
};
public class ExtDemo08{
	public static void main(String args[]){
		Student stu = new Student("张三",30,"西安电大") ;	//  学生
		System.out.println("姓名：" + stu.getName()) ;
		System.out.println("年龄：" + stu.getAge()) ;
		System.out.println("学校：" + stu.getSchool()) ;
	}
};

面向对象之继承

原文：http://blog.csdn.net/u014492609/article/details/44204513