设计模式

设计模式:

为什么要设计?

1.      软件的复用

2.      软件的维护

 

开闭原则:

对高层的修改关闭,对低层的扩展开放

模板方法:它实现了开闭原则

package MY.module01.sjms.kbyz;

 

public class TestCET6 {

 

      

       public static void main(String[] args) {

              // TODO Auto-generated method stub

              CET6 c=new ConcretCET6();

              c.passCET6();

       }

 

}

package MY.module01.sjms.kbyz;

 

public abstract class CET6 {

       //高层业务逻辑

       public final void passCET6(){

              listen();

              say();

       }

       //提供给低层实现的业务

       abstract protected void listen();

       abstract protected void say();

}

package MY.module01.sjms.kbyz;

 

public class ConcretCET6 extends CET6{

 

       @Override

       protected void listen() {

              // TODO Auto-generated method stub

              System.out.println("listen");

       }

 

       @Override

       protected void say() {

              // TODO Auto-generated method stub

              System.out.println("say");

       }

      

}

 

里氏代换原则:

任何父类适用的地方,子类一定适用,子类可以当父类用

策略模式:实现了里氏代换原则,解决了可选算法的问题

什么是策略模式?针对共同的问题,提供解决方案或指导原则或好坏结果

package MY.module01.sjms.celuemoshi;

 

public class Client {

 

      

       public static void main(String[] args) {

              // TODO Auto-generated method stub

              Context c=new Context();//算法选择器

//          c.setD(new dis2());

              c.setD(new dis1());//选择折扣

              c.getprice(100);//打折

       }

 

}

package MY.module01.sjms.celuemoshi;

 

public class Context {

       private DisCount d;

 

       public void setD(DisCount d) {

              this.d = d;

       }

      

       public void getprice(double price){

               System.out.println(d.discout(price));

       }

}

package MY.module01.sjms.celuemoshi;

 

public class dis1 extends DisCount{

 

       @Override

       public double discout(double price) {

              // TODO Auto-generated method stub

              return price*0.8;

       }

 

}

package MY.module01.sjms.celuemoshi;

 

public class dis2 extends DisCount{

 

       @Override

       public double discout(double price) {

              // TODO Auto-generated method stub

              return price;

       }

 

}

package MY.module01.sjms.celuemoshi;

 

public abstract class DisCount {

       public abstract double discout(double price);

}