基於有了OO的基礎後，開始認真學習設計模式！設計模式是java設計中必不可少的！
Apple.java
package strategy;/** * * @author Andy * */ public class Apple implements Discountable { //重量private double weight; //單價實際開發中設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麼就寫什麼打折算法// 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); } }