Java 面向对象：继承多态、覆盖override

package com.neusoft.override;

public class A {
	public String toString() {
		return "123456";// 继承Object并重写

	}

	int a = 2;

	public void func() {
		System.out.println("1111111111");
	}

	public static void main(String[] args) {
		A a = new A();
		System.out.println(a);// 等同于a.toString()默认
	}

}
           

package com.neusoft.override;
/**
 * 继承多态
 * 满足多态的条件：
 * 1.要有继承关系
 * 2.方法重写
 * 3.父类的引用指向子类的对象
 * @author Administrator
 *
 */
public class B extends A {
	int a = 2;

	public void func() {
		System.out.println("2222222222");
	}

	public static void main(String[] args) {
//		B b = new B();
//		b.func();//2222222222
//		System.out.println(b.a);//2
		
		//多态
		A x = new B();//父类引用指向子类
		x.func();//无论如何，涉及到重写，就执行子类2222222222
		System.out.println(x.a);//1
		 
		A a = new A();
		a.func();//1111111111
		
		
	}
}
           

package com.neusoft.override;

/**
 * 方法的覆盖override： /重写rewrite
 * 1.要有继承关系
 * 2.子类要重写父类中的方法，要求子类中的方法完全相同（访问权限，方法名称，参数，返回值类型）
 * 3.为什么要使用方法重写？子类的方法对象父类方法的拓展与改造
 * 
 */
public 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;
	}

	

	
	public void printInfo() {
		System.out.println(name+"----"+age);
	}
}
           

package com.neusoft.override;


public class Student extends Person{
	private String school;
	
	public String getSchool() {
		return school;
	}

	public void getSchool(String school) {// overload 重载
		this.school = school;// 初始化

	}
	
	public void printInfo(){
		setAge(2);
		System.out.println(getName()+getAge()+school);
		
	}
	public static void main(String[] args) {
		Student student = new Student();
		student.printInfo();
		Person person = new Person();
		person.printInfo();
		
	}
}