第5题 编码创建打印机类定义抽象方法,创建2个子类,并重写方法,然后测试,再添加一个子类,重写方法,修改测试,实现功能
/**
* 打印机类
* 抽象类,抽象方法*/
public abstract class Printer {
public abstract void print() ;
}
/**
* 针式打印机
*/
public class DotMatrixPrinter extends Printer {
public void print() {
System.out.println("用针式打印机打印!");
}
}
/**
* 喷墨打印机
*/
public class InkpetPrinter extends Printer {
public void print() {
System.out.println("用喷墨打印机打印");
}
}
/**
* 测试类
*/
public class Test {
public static void main(String[] args) {
Printer dot = new DotMatrixPrinter();
Printer inkpet = new InkpetPrinter();
dot.print();
inkpet.print();
}
}
/**
* 新增激光打印机类
*/
public class LaserPrinter extends Printer {
public void print() {
System.out.println("用激光打印机打印");
}
}
/**
* 修改测试类
*/
public class Test {
public static void main(String[] args) {
Printer dot = new DotMatrixPrinter();
Printer inkpet = new InkpetPrinter();
Printer laser = new LaserPrinter();
dot.print();
inkpet.print();
laser.print();
}
}
第6题 使用多态实现牛犇招待不同的朋友
/**
* 朋友类(抽象类,抽象方法)
*/
public abstract class Friends {
private String name;
private String comeFrom;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getComeFrom() {
return comeFrom;
}
public void setComeFrom(String comeFrom) {
this.comeFrom = comeFrom;
}
public abstract void show();
}
/**
* 子类王小强类
*/
public class WangXiaoQiang extends Friends {
public WangXiaoQiang() {
super.setName("王小强");
super.setComeFrom("中国");
}
public void show() {
System.out.println("我是牛犇的朋友"+this.getName()+",我来自"+this.getComeFrom()+",我喜欢吃四川菜,练太极拳!");
}
}
/**
* 子类约翰类
*/
public class Jon extends Friends {
public Jon() {
super.setName("约翰");
super.setComeFrom("美国");
}
public void show() {
System.out.println("我是牛犇的朋友"+this.getName()+",我来自"+this.getComeFrom()+",我喜欢吃披萨,打橄榄球!");
}
}
/*** 主人类
*/
public class Niuben {
public Friends getFriend(int num) {
if(num==1) {
return new WangXiaoQiang();
}else {
return new Jon();
}
}
public void entertain(Friends friend) {
if (friend instanceof WangXiaoQiang) {
WangXiaoQiang wang = (WangXiaoQiang) friend;
wang.show();
} else if (friend instanceof Jon) {
Jon jon = (Jon) friend;
jon.show();
}
}
} /**
* 测试类
*/
public class TestFriends {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
System.out.println("请选择到访的朋友(1.王小强 2.约翰)");
int num = in.nextInt();
Niuben niu = new Niuben();
niu.entertain(niu.getFriend(num));
}
}