设计模式——策略模式

package com.demo;

import java.lang.reflect.Constructor;

public class Client {
    public static void main(String[] args) {
        //不使用策略模式
        Meidun meidun=new Meidun(5);
        meidun.pay();
        //使用策略模式
        PinDaoDao pinDaoDao=new PinDaoDao(new HalfDisCount());
        pinDaoDao.pay();
        //使用反射优化策略模式
        PinDaoDao pinDaoDaoBetter=new PinDaoDao("com.demo.OneDisCount");
        pinDaoDaoBetter.pay();

    }
}
class Meidun{
    int discount;
    public Meidun(int discount){
        this.discount=discount;
    }
    public void pay(){
        if(discount==1){
            System.out.println("打一折");
        }else if(discount==5){
            System.out.println("打五折");
        }else if(discount==8){
            System.out.println("打八折");
        }else {
            System.out.println("打全折");
        }
    }
}
class PinDaoDao{
    private DisCount disCount;
    public PinDaoDao(DisCount disCount){
        this.disCount=disCount;
    }
    public  PinDaoDao(String classPath){
        try {
            Class clazz =  Class.forName(classPath);
            Constructor constructor = clazz.getDeclaredConstructor();
            this.disCount = (DisCount) constructor.newInstance();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public void pay(){
        disCount.payWithDisCount();
    }
}
interface DisCount{
    void payWithDisCount();
}
class HalfDisCount implements DisCount{
    @Override
    public void payWithDisCount() {
        System.out.println("五百万的龟苓膏打五折就是二十五万");
    }
}
class OneDisCount implements DisCount{
    @Override
    public void payWithDisCount() {
        System.out.println("三百万的老残酸菜面打一折就是三百五十万");
    }
}