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Java設(shè)計模式之Strategy模式

更新時間：2016年07月17日 21:43:11 投稿：hebedich

Strategy模式即策略模式，就是將一個算法的不同實現(xiàn)封裝成一個個單獨的類，這些類實現(xiàn)同一個接口，使用者直接使用該接口來訪問具體的算法。這個樣子，使用者就可以使用不同的算法來實現(xiàn)業(yè)務(wù)邏輯了。

基于有了OO的基礎(chǔ)后，開始認(rèn)真學(xué)習(xí)設(shè)計模式！設(shè)計模式是java設(shè)計中必不可少的！

Apple.java

package strategy;
/**
 * 
 * @author Andy
 *
 */
 
public class Apple implements Discountable {
  //重量
  private double weight;
  //單價 實際開發(fā)中 設(shè)計金錢等精確計算都是BigDecimal;
    private double price;
    //按購買量打折
  // private Discountor d = new AppleWeightDiscountor();
    //按購買總價打折
    private Discountor d = new ApplePriceDiscountor();
     
  public double getWeight() {
    return weight;
  }
   
  public void setWeight(double weight) {
    this.weight = weight;
  }
   
  public double getPrice() {
    return price;
  }
   
  public void setPrice(double price) {
    this.price = price;
  }

  public Apple (double weight,double price ){
   
    super();
    this.weight=weight;
    this.price=price;
  }
 
  @Override
  public void discountSell() {
     d.discount(this);
  }  
}

Banana.java

package strategy;
/**
 * 
 * @author Andy
 *
 */
public class Banana implements Discountable {
  //重量
  private double weight;
////單價 實際開發(fā)中 涉及金錢等精確計算都是用BigDecimal
  private double price;
   
  public Banana(double weight, double price) {
    super();
    this.weight = weight;
    this.price = price;
  }
 
  public double getWeight() {
    return weight;
  }
   
  public void setWeight(double weight) {
    this.weight = weight;
  }
   
  public double getPrice() {
    return price;
  }
   
  public void setPrice(double price) {
    this.price = price;
  }
 
  @Override
  public void discountSell() {
    //打折算法
    if(weight < 5) {
      System.out.println("Banana未打折價錢: " + weight * price);
    }else if(weight >= 5 && weight < 10) {
      System.out.println("Banana打八八折價錢: " + weight * price * 0.88 );
    }else if(weight >= 10) {
      System.out.println("Banana打五折價錢: " + weight * price * 0.5 );
    }    
     
  }

}

Market.java

package strategy;
/**
 * 
 * @author Andy
 *
 */
public class Market {
   
  /**
   * 對可打折的一類事物進(jìn)行打折
   * @param apple
   */

  public static void discountSell(Discountable d) {
    d.discountSell();

}
}

Discountable.java

package strategy;
/**
 * 
 * @author Andy
 *
 */
public interface Discountable {
  public void discountSell();
}

Test.java

package strategy;
/**
 * 
 * @author Andy
 *
 */
public class Test {
   
  /**
   * 
   * @param args
   */
 
  public static void main(String[] args) {
//    只能對蘋果打折 還不能對通用的一類事物打折 而且都是要賣什么就寫什么打折算法 
//   其實每類事物打折算法又是不一致的
    Discountable d = new Apple(10.3, 3.6);
    Discountable d1= new Banana(5.4,1.1);
      Market.discountSell(d);
      Market.discountSell(d1);
     
 
  }
 
}

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