[历史归档]本文原发布于 cstriker1407.info 个人博客，内容为历史存档，仅供参考。
发布时间：2013-10-17｜ 标题：设计模式学习笔记：建造者模式｜分类：编程 / 设计模式 / java ｜标签：设计模式·java·建造者模式

建造者模式（Builder Pattern）将复杂对象的构建过程与其表示分离，使同样的构建流程可以创建不同的产品。

示例代码：https://github.com/cstriker1407/design_pattern

1. 将要制造的元素抽象出来，将公用业务封装在抽象类中

/** * 父类设计成抽象类，供子类继承。 */abstractclassCarModel{privatebooleanbIsAlarm=false;// start/stop/alarm 对外不可见，设计为 protectedprotectedabstractvoidstart();protectedabstractvoidstop();protectedabstractvoidalarm();// run 设置为 final，固化业务流程，防止子类重写publicfinalvoidrun(){start();if(isAlarm()){alarm();}stop();}// 钩子方法：子类可通过 setAlarm 控制是否触发 alarmprivatebooleanisAlarm(){returnbIsAlarm;}publicfinalvoidsetAlarm(booleanisAlarm){this.bIsAlarm=isAlarm;}}

2. 分别实例化两个具体的元素

classACarextendsCarModel{@Overrideprotectedvoidstart(){System.out.println("A Car Start");}@Overrideprotectedvoidstop(){System.out.println("A Car Stop");}@Overrideprotectedvoidalarm(){System.out.println("A Car Alarm");}}classBCarextendsCarModel{@Overrideprotectedvoidstart(){System.out.println("B Car Start");}@Overrideprotectedvoidstop(){System.out.println("B Car Stop");}@Overrideprotectedvoidalarm(){System.out.println("B Car Alarm");}}

3. 将制造类抽象出来，屏蔽上层对具体元素的依赖

abstractclassCarBuilder{publicabstractvoidsetAlarm(booleanisAlarm);publicabstractCarModelgetCar();}classACarBuilderextendsCarBuilder{privateACaraCar=newACar();@OverridepublicvoidsetAlarm(booleanisAlarm){aCar.setAlarm(isAlarm);}@OverridepublicCarModelgetCar(){returnaCar;}}classBCarBuilderextendsCarBuilder{privateBCarbCar=newBCar();@OverridepublicvoidsetAlarm(booleanisAlarm){bCar.setAlarm(isAlarm);}@OverridepublicCarModelgetCar(){returnbCar;}}

4. 控制类与测试代码

classBuilderDirector{privateACarBuilderaCarBuilder=newACarBuilder();privateBCarBuilderbCarBuilder=newBCarBuilder();publicACargetACar(){aCarBuilder.setAlarm(true);return(ACar)aCarBuilder.getCar();}publicBCargetBCar(){bCarBuilder.setAlarm(false);return(BCar)bCarBuilder.getCar();}}publicclassBuilderTest{publicstaticvoidtest(){BuilderDirectordirector=newBuilderDirector();director.getACar().run();director.getBCar().run();}}

备注

1. 上述代码部分来自《设计模式之禅》
2. 建造者模式定义后续补充