1.编码创建一个打印类Printer,定义抽象方法print（）；创建两个子类，即针式打印机类DotMatrixPrinter和喷墨打印机类LnkpetPrinter,并在各自类中重写方法print(),编写测试类实现两种打印机打印，在添加一个激光打印机子类LaserPrinter,重写方法print（），修改测试类实现该打印机打印。
package com.homework.demo.test5_5;
/**
* 打印机抽象父类
* @author suixin
*
*/
public abstract class Printer {
/**
* 抽象打印方法
*/
public abstract void print();
}
package com.homework.demo.test5_5;
/**
* 针式打印机类
* @author suixin
*
*/
public class DotMatrixPrinter extends Printer{
@Override
public void print() {
// TODO Auto-generated method stub
System.out.println("针式打印机");
}
}
package com.homework.demo.test5_5;
/**
* 喷墨打印机类
* @author suixin
*
*/
public class InkpetPrinter extends Printer{
@Override
public void print() {
// TODO Auto-generated method stub
System.out.println("喷墨打印机");
}
}
package com.homework.demo.test5_5;
/**
* 激光打印机类
* @author suixin
*
*/
public class LaserPrinter extends Printer{
@Override
public void print() {
// TODO Auto-generated method stub
System.out.println("激光打印机");
}
}
package com.homework.demo.test5_5;
public class Test {
public static void main(String[] args) {
// TODO Auto-generated method stub
Printer p = new DotMatrixPrinter(); //针式打印机
p.print();
Printer p1 = new InkpetPrinter(); //喷墨打印机
p1.print();
Printer p2 = new LaserPrinter(); //激光打印机
p2.print();
}
}
2.请使用多态实现以下需求，牛犇有两个很要好的朋友，一个是中国的王小强，喜欢吃四川菜，练太极拳，另一个是美国的约翰，喜欢吃披萨，打橄榄球，每当朋友来拜访时，牛犇都会按各自的喜好招待他们。
package com.homework.demo.test5_6;
/**
* 主人类
* @author suixin
*
*/
public abstract class Master {
String masterName = "牛犇"; //主人姓名
String name = " "; //客人姓名
String eat = " "; //吃的菜
String hobby = " "; //客人的爱好
public abstract void serve(); //抽象招待方法
public void serve1(Master master) {
if (master instanceof Guest1) { //如果是王小强
Guest1 guest1 = (Guest1)master;
guest1.serve();
}else if (master instanceof Guest2) { //如果是约翰
Guest2 guest2 = (Guest2)master;
guest2.serve();
}
}
}
package com.homework.demo.test5_6;
/**
* 王小强类
* @author suixin
*
*/
public class Guest1 extends Master{
/**
* 招待王小强的方法
*/
public void serve() {
super.name = "王小强";
super.hobby = "练太极拳";
super.eat = "吃四川菜";
System.out.println(super.masterName + "在招待" + super.name + "一起" + super.eat+","+super.hobby);
}
}
package com.homework.demo.test5_6;
/**
* 约翰类
* @author suixin
*
*/
public class Guest2 extends Master {
@Override
public void serve() {
// TODO Auto-generated method stub
super.name = "约翰";
super.hobby = "打橄榄球";
super.eat = "吃披萨";
System.out.println(super.masterName + "在招待" + super.name + "一起" + super.eat + ","+ super.hobby);
}
}
package com.homework.demo.test5_6;
/**
* 测试类
*/
import java.util.Scanner;
public class Test {
public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner scanner = new Scanner(System.in);
System.out.print("请问是谁哪个朋友来拜访（1.王小强 2.约翰）：");
if (scanner.nextInt() == 1) { //王小强时
Master master = new Guest1();
master.serve1(master);
}else { //约翰
Master master = new Guest2();
master.serve1(master);
}
}
}