Java中类的继承,重写

1.自编案例总结包的创建和导入
/*
*包的创建
*/
package com.by3g.test;
import java.util.Scanner;
/*
*此类实现通过：调用有参方法和无参方法(function)求出三角形的面积。
*/
class Area
{
public double width,height,area;
="漫步云端";
v.functionVilla();
}
}
运行结果：
3.自编案例总结super的两种用法:super()和super.父类方法()
class Parent
{
double width,height,depth;
Parent()
{
System.out.println("调用Parent构造函数！");
}
}
运行结果：
{
super(width,height,length);
}
void function()
{
area=width*length;
System.out.println("\n此别墅："+name+"占地:"+area+"平方米高度为："+height);
}
}
class Host
{
public static void main(String[] args)
{
super(width,height,depth);
super.function();
System.out.println("调用Sub有参数构造函数！");
}
}
class Demo extends Parent
{
public static void main(String[] args)
{
Sub sub;
{
Building b;
b=new Villa(120,100,100.35);
//function重写后不再是调用父类的方法
b.function(;
Villa v=new Villa();
v.width=100;
v.height=50;
v.length=120;
="漫步云端";
v.function();
System.out.println("三角形的面积为："+(width*height/2)+"平方米");
}
/* Sss
*类的功能方法实现，要求传参数过来（重载）
*/
public double function(double width,double height)
{
area=width*height/2;
}
}
运行结果：
2.自编案例总结类的单继承(包括属性和方法的继承)
/*
*建筑类是父类
*/
class Building
{
double width,height,length,area;
Building()
{
}
Building(double width,double height,double length)
return area;
}
}
//Create类继承Area的所有方法和属性
public class Create extends Area
{
}
/*
*包的导入
*/
import com.by3g.test.Create;
/*
*共类继承Create类
*/
public class Input extends Create
}
Parent(double width,double height,double depth)
{
this.width=width;
this.height=height;
this.depth=depth;
}
void function()
{
System.out.println("三者之积为："+height*width*depth);
{
this.width=width;
this.height=height;
this.length=length;
}
void function()
{
area=width*length;
System.out.println("此建筑物的占地面积为："+area+"平方米高度为："+height);
}
}
class Villa extends Building
Scanner scanf=new Scanner(System.in);
/*
*功能实现，要求输入并求出三角形的面积（也是重载）
*/
public void function()
{
System.out.print("请输入三角行的长度，宽度:");
width=scanf.nextDouble();
height=scanf.nextDouble();
{
public static void main(String[] args)
{
Input a=new Input();
//Area中无参重载调用
a.function();
//Area中有参重载调用
System.out.println("\n自带参数的三角形面积为："+a.function(100.2,122)+"平方米");
}
}
class Host
{
public static void main(String[] args)
{
Building b;
b=new Villa(120,100,100.35);
b.function();
Villa v=new Villa();
v.width=100;
v.height=50;
v.length=120;
sub=new Sub();
sub=new Sub(12,12,12);
Demo d;
d=new Demo();
}
Demo()
{
super(10,10,10);
super.function();
}
}
运行结果：
4.自编案例总结方法重写(override)
/*
*建筑类是父类
*/
class Building
{
double width,height,length,area;
Building()
{
}
Building(double width,double height,double length)
{
this.width=width;
this.height=height;
this.length=length;
{
String name;
Villa(){}
Villa(double width,double height,double length)
{
super(width,height,length);
}
void functionVilla()
{
area=width*length;
System.out.println("\n此别墅："+name+"占地:"+area+"平方米高度为："+height);
}
void function()
{
area=width*length;
System.out.println("此建筑物的占地面积为："+area+"平方米高度为："+height);
}
}
class Villa extends Building
{
String name;
Villa(){}
Villa(double width,double height,double length)
}
void function1(double a)
{
System.out.println("zzzzzzzz");
}
}
class Sub extends Parent
{
Sub()
{
System.out.println("调用Sub中的无参构造函数！");
}
Sub(double width,double height,double depth)