java中抽象类、抽象方法、接口与实现接口实例详解

//父类.并且使用用接口
package cn.yjlblog.wwww;

public interface Compute {
 int computer(int n,int m);//抽象方法，胜率abstract ，public


}

//子类add 实现加法运算
package cn.yjlblog.wwww;

public class add implements Compute{

 @Override //接口的实现类和抽象类的子类是一样的，要想可以使用new 一个对象，就必须对“抽象类”里的方法
   //进行重写
 public int computer(int n, int m) {
  // TODO Auto-generated method stub
  return n+m;
 }


}

package cn.yjlblog.wwww;
//子类subtract 实现减法运算
public class subtract implements Compute{

 @Override
 public int computer(int n, int m) {
  // TODO Auto-generated method stub
  return n-m;
 }

}

子类multiplied 实现乘法运算
package cn.yjlblog.wwww;

public class multiplied implements Compute{

 @Override
 public int computer(int n, int m) {
  // TODO Auto-generated method stub
  return n*m;
 }


}

package cn.yjlblog.wwww;
//子类divided 实现整除运算
public class divided implements Compute{

 @Override
 public int computer(int n, int m) {
  // TODO Auto-generated method stub
  return n/m;
 }


}

//应用类UseComepute 用来
package cn.yjlblog.wwww;

public class UseComepute {
 public void useCom(Compute com,int one,int two){
  int x = com.computer(one, two);
  System.out.println("运算结果为："+x);

 }


}

//测试类Test
package cn.yjlblog.wwww;

public class Test {
 public static void main(String[] args) {
  UseComepute uc = new UseComepute();//应用类生成对象，使用useCome 方法
  int one = 10;
  int two = 20;
  Compute ad = new add();//接口的多态
  Compute sub = new subtract();
  Compute mul= new multiplied();
  Compute div = new divided();
  uc.useCom(ad, one, two);
  uc.useCom(sub, one, two);
  uc.useCom(mul, one, two);
  uc.useCom(div, one, two);

  //哈哈，类的名字忘记大写了

 }

}

public abstract void Printer() {
public void open() {
system.out.print("打印机开启");
}
public void close() {
system.out.print("打印机关闭");
}
abstract void print(); //把print方法定义为抽象方法
}

public HPPrinter extends Printer {
void print(){ //必须重写抽象方法print() 
system.out.print("惠普打印机开始打印");
};
}

public CanonPrinter extends Printer {
void print(){ //必须重写抽象方法print()
system.out.print("佳能打印机开始打印");
};
}

public abstract class People { //关键词abstract，声明该类为抽象类
 void Num();      
 abstract void Name();    //声明该方法为抽象方法
}
 
Interface Person {
  void Num();
  void Name();
}