手机端便民服务平台网站建设,wordpress论坛主题模板,郑州网站建设最低价,中企动力的网站开发语言工厂模式简单工厂实现工厂模式实现简单工厂 VS 工厂方法商场收银程序再再升级#xff08;简单工厂策略装饰工厂方法#xff09;工厂方法模式总结简单工厂实现 在简单工厂类中#xff0c;通过不同的运算符#xff0c;创建具体的运算类。
public class OperationFactory {pu…
工厂模式简单工厂实现工厂模式实现简单工厂 VS 工厂方法商场收银程序再再升级简单工厂策略装饰工厂方法工厂方法模式总结简单工厂实现 在简单工厂类中通过不同的运算符创建具体的运算类。
public class OperationFactory {public static Operation createOperate(String operate){Operation oper null;switch (operate) {case :oper new Add();break;case -:oper new Sub();break;case *:oper new Mul();break;case /:oper new Div();break;}return oper;}
}
工厂模式实现 工厂类
// 工厂接口
public interface IFactory {public Operation createOperation();
}
//减法工厂
public class SubFactory implements IFactory {public Operation createOperation(){return new Sub();}
}
//加法工厂
public class AddFactory implements IFactory {public Operation createOperation(){return new Add();}
}
//除法工厂
public class DivFactory implements IFactory {public Operation createOperation(){return new Div();}
}
//乘法工厂
public class MulFactory implements IFactory {public Operation createOperation(){return new Mul();}
}运算类
// 抽象运算类
public abstract class Operation {public double getResult(double numberA, double numberB){return 0d;}
}
// 减法运算类
public class Sub extends Operation {public double getResult(double numberA, double numberB){return numberA - numberB;}
}
// 加法运算类
public class Add extends Operation {public double getResult(double numberA, double numberB){return numberA numberB;}
}
// 除法运算类
public class Div extends Operation {public double getResult(double numberA, double numberB){if (numberB 0){System.out.println(除数不能为0);throw new ArithmeticException();}return numberA / numberB;}
}
// 乘法运算类
public class Mul extends Operation {public double getResult(double numberA, double numberB){return numberA * numberB;}
}运算工厂
public class OperationFactory {public static Operation createOperate(String operate){Operation oper null;IFactory factory null;switch (operate) {case :// 隐藏了具体运算类的创建过程factory new AddFactory();break;case -:factory new SubFactory();break;case *:factory new MulFactory();break;case /:factory new DivFactory();break;}oper factory.createOperation(); return oper;}
}客户端
public class Test {public static void main(String[] args){System.out.println(**********************************************); System.out.println(《大话设计模式》代码样例);System.out.println(); try {Scanner sc new Scanner(System.in);System.out.println(请输入数字A); double numberA Double.parseDouble(sc.nextLine());System.out.println(请选择运算符号(、-、*、/)); String strOperate sc.nextLine();System.out.println(请输入数字B); double numberB Double.parseDouble(sc.nextLine());Operation oper OperationFactory.createOperate(strOperate);double result oper.getResult(numberA,numberB);System.out.println(结果是result); }catch(Exception e){System.out.println(您的输入有错e.toString()); }System.out.println();System.out.println(**********************************************);}
}简单工厂 VS 工厂方法
简单工厂模式的最大优点在于工厂类中包含必要的逻辑判断根据客户端的选择条件动态实例化相关的类对于客户端来说去除了与具体产品的依赖。
在简单工厂中由于每次增加运算类都需要在工厂类中增加Case分支条件。这对于工厂类来说不是一个好办法频繁的进行修改违反了开放-封闭原则。
尽量将长的代码分派切割成小段再将每一小段封装起来减少每段代码之间的耦合这样风险就分散了需要修改或扩展的难度就降低了。
可以将加减乘除基础的运算类由一个基础运算工厂进行创建增加的指数对数运算类再增加一个高级运算工厂类进行创建。就不会影响基础运算类的部分。
// 抽象工厂接口
public interface IFactory {public Operation createOperation(String operType);
}
//基础运算工厂
public class FactoryBasic implements IFactory {public Operation createOperation(String operType){Operation oper null;switch (operType) {case :oper new Add();break;case -:oper new Sub();break;case *:oper new Mul();break;case /:oper new Div();break;} return oper;}
}
//高级运算工厂
public class FactoryAdvanced implements IFactory {public Operation createOperation(String operType){Operation oper null;switch (operType) {case pow:oper new Pow();//指数运算类实例break;case log:oper new Log();//对数运算类实例break;//此处可扩展其他高级运算类的实例化但修改//当前工厂类不会影响到基础运算工厂类}return oper;}
}运算工厂类
public class OperationFactory {public static Operation createOperate(String operate){Operation oper null;IFactory factory null;switch (operate) {case :case -:case *:case /://基础运算工厂实例factorynew FactoryBasic();break;case pow:case log://高级运算工厂实例factorynew FactoryAdvanced();break;} //利用多态返回实际的运算类实例oper factory.createOperation(operate);return oper;}
}客户端
public class Test {public static void main(String[] args){System.out.println(**********************************************); System.out.println(《大话设计模式》代码样例);System.out.println(); try {Scanner sc new Scanner(System.in);System.out.println(请输入数字A); double numberA Double.parseDouble(sc.nextLine());System.out.println(请选择运算符号(、-、*、/)); String strOperate sc.nextLine();System.out.println(请输入数字B); double numberB Double.parseDouble(sc.nextLine());Operation oper OperationFactory.createOperate(strOperate);double result oper.getResult(numberA,numberB);System.out.println(结果是result); }catch(Exception e){System.out.println(您的输入有错e.toString()); }System.out.println();System.out.println(**********************************************);}
}在新的 OperationFactory类已经不存在实例化运算子类的代码在这个代码里全是接口和具体工厂类。将实例化的过程放到了子类工厂中。这就是针对接口编程不要对实现编程。
工厂方法模式Factory Method定义一个创建对象的接口让子类决定实例化哪一个类。工厂方法使一个类的实例化延迟到其子类。
工厂方法模式结构图
商场收银程序再再升级简单工厂策略装饰工厂方法
在上一版代码中通过简单工厂对于不同的条件生成具体的收费策略类。可以使用工厂方法模式替代简单工厂。 对于不同的收费策略可以分为两类先打折后满减和先满减后打折。
// 工厂接口
public interface IFactory {public ISale createSalesModel(); //创建销售模式
}
//先打折再满减类
public class CashRebateReturnFactory implements IFactory {private double moneyRebate 1d;private double moneyCondition 0d;private double moneyReturn 0d;public CashRebateReturnFactory(double moneyRebate,double moneyCondition,double moneyReturn){this.moneyRebate moneyRebate;this.moneyCondition moneyCondition;this.moneyReturn moneyReturn;}//先打x折,再满m返npublic ISale createSalesModel(){CashNormal cn new CashNormal();CashReturn cr1 new CashReturn(this.moneyCondition,this.moneyReturn); CashRebate cr2 new CashRebate(this.moneyRebate);cr1.decorate(cn); //用满m返n算法包装基本的原价算法cr2.decorate(cr1); //打x折算法装饰满m返n算法return cr2; //将包装好的算法组合返回}
}
//先满减再打折类
public class CashReturnRebateFactory implements IFactory {private double moneyRebate 1d;private double moneyCondition 0d;private double moneyReturn 0d;public CashReturnRebateFactory(double moneyRebate,double moneyCondition,double moneyReturn){this.moneyRebate moneyRebate;this.moneyCondition moneyCondition;this.moneyReturn moneyReturn;}//先满m返n,再打x折public ISale createSalesModel(){CashNormal cn2 new CashNormal();CashRebate cr3 new CashRebate(this.moneyRebate);CashReturn cr4 new CashReturn(this.moneyCondition,this.moneyReturn); cr3.decorate(cn2); //用打x折算法包装基本的原价算法cr4.decorate(cr3); //满m返n算法装饰打x折算法return cr4; //将包装好的算法组合返回}
}// 收费接口
public interface ISale {public double acceptCash(double price,int num);
}
public class CashNormal implements ISale {//正常收费原价返回public double acceptCash(double price,int num){return price * num; }
}
public class CashSuper implements ISale {protected ISale component;//装饰对象public void decorate(ISale component) {this.component component;}public double acceptCash(double price,int num){if (this.component ! null){//若装饰对象存在则执行装饰的算法运算return this.component.acceptCash(price,num); }else return 0d;}
}
public class CashRebate extends CashSuper {private double moneyRebate 1d;//打折收费。初始化时必需输入折扣率。八折就输入0.8public CashRebate(double moneyRebate){this.moneyRebate moneyRebate;}//计算收费时需要在原价基础上乘以折扣率public double acceptCash(double price,int num){double result price * num * this.moneyRebate;return super.acceptCash(result,1);}
}
public class CashReturn extends CashSuper {private double moneyCondition 0d; //返利条件private double moneyReturn 0d; //返利值//返利收费。初始化时需要输入返利条件和返利值。//比如“满300返100”就是moneyCondition300,moneyReturn100public CashReturn(double moneyCondition,double moneyReturn){this.moneyCondition moneyCondition;this.moneyReturn moneyReturn;}//计算收费时当达到返利条件就原价减去返利值public double acceptCash(double price,int num){double result price * num;if (moneyCondition0 result moneyCondition)result result - Math.floor(result / moneyCondition) * moneyReturn; return super.acceptCash(result,1); }
}在 CashContext 中使用具体的工厂来得到不同的收费策略类。
public class CashContext {private ISale cs; //声明一个ISale接口对象//通过构造方法传入具体的收费策略public CashContext(int cashType){IFactory fsnull;switch(cashType) {case 1://原价fs new CashRebateReturnFactory(1d,0d,0d);break;case 2://打8折fs new CashRebateReturnFactory(0.8d,0d,0d);break;case 3://打7折fs new CashRebateReturnFactory(0.7d,0d,0d);break;case 4://满300返100fs new CashRebateReturnFactory(1,300d,100d);break;case 5://先打8折,再满300返100fs new CashRebateReturnFactory(0.8d,300d,100d);break;case 6://先满200返50再打7折fs new CashReturnRebateFactory(0.7d,200d,50d);break;}this.cs fs.createSalesModel();}public double getResult(double price,int num){//根据收费策略的不同获得计算结果return this.cs.acceptCash(price,num);}
}客户端
public class Test {public static void main(String[] args){System.out.println(**********************************************); System.out.println(《大话设计模式》代码样例);System.out.println(); int discount 0; //商品折扣模式double price 0d; //商品单价int num 0; //商品购买数量double totalPrices 0d;//当前商品合计费用double total 0d; //总计所有商品费用Scanner sc new Scanner(System.in);do {System.out.println(商品折扣模式如下:); System.out.println(1.正常收费); System.out.println(2.打八折); System.out.println(3.打七折); System.out.println(4.满300送100); System.out.println(5.先打8折再满300送100); System.out.println(6.先满200送50再打7折); System.out.println(请输入商品折扣模式:); discount Integer.parseInt(sc.nextLine());System.out.println(请输入商品单价); price Double.parseDouble(sc.nextLine());System.out.println(请输入商品数量); num Integer.parseInt(sc.nextLine());System.out.println(); if (price0 num0){//根据用户输入将对应的策略对象作为参数传入CashContext对象中CashContext cc new CashContext(discount);//通过Context的getResult方法的调用可以得到收取费用的结果//让具体算法与客户进行了隔离totalPrices cc.getResult(price,num);total total totalPrices;System.out.println(); System.out.println(单价 price 元 数量 num 合计 totalPrices 元); System.out.println();System.out.println(总计 total元); System.out.println();}} while(price0 num0);System.out.println();System.out.println(**********************************************);}
}工厂方法模式总结
工厂方法克服了简单工厂违背开放-封闭原则的缺点又保持封装对象创建过程的优点。 工厂方法模式是简单工厂模式的进一步抽象和推广。是对获取对象过程的进一步抽象。
工厂方法模式的好处
对于复杂的参数的构造对象可以很好地对外层屏蔽代码的复杂性。很好的解耦能力针对接口编程屏蔽了细节。
