09_工厂和单例模式_思路与案例

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1、简单工厂模式农场（FruitGardener）生产的水果（Fruit）有三种：葡萄（Grape）、苹果（Apple）和草莓（Strawberry）publicinterfaceFruit{publicvoidplan();publicvoidgrow();publicvoidharvest();}publicclassAppleimplementsFruit{publicvoidgrow(){System.out.println("苹果在生长...");}}publicclassGrapeimplementsFruit{publicvo

2、idgrow(){System.out.println("葡萄在生长...");}}publicclassStrawberryimplementsFruit{publicvoidgrow(){System.out.println("草莓在生长...");}}publicclassFruitGardener{publicstaticFruitcreateFruit(Stringname){if("apple".equals(name)){returnnewApple();}if("grape".equals(name)){returnne

3、wGrape();}if("strawberry".equals(name)){returnnewStrawberry();}returnnewApple();}}publicclassTest{publicstaticvoidmain(String[]args){FruitGardener.createFruit("apple").plan();FruitGardener.createFruit("grape").grow();FruitGardener.createFruit("strawberry").grow();}}随着业务的

4、扩大，农场生产的果品种类越来越多，按照原有的模式，由一个农场生产所有种类的水果，导致任务过重、判断过多，逻辑过于复杂，容易出错，难于管理，牵一发而动全身，增加新品种困难，需要改进设计模式，适应于新的情况。工厂方法模式将农场分为若干种：苹果农场负责生产苹果、草莓农场负责生产草莓、葡萄农场负责生产葡萄publicinterfaceFruit{//抽象的产品publicvoidgrow();}publicinterfaceFruitFactoy{//抽象的工厂publicFruitcreateFruit();}publicclassApple

5、implementsFruit{//具体的产品publicvoidgrow(){System.out.println("苹果在生长...");}}publicclassGrapeimplementsFruit{//具体的产品publicvoidgrow(){System.out.println("葡萄在生长...");}}publicclassStrawberryimplementsFruit{//具体的产品publicvoidgrow(){System.out.println("草莓在生长...");}}publicclassAppl

6、eFactoryimplementsFruitFactoy{//具体的工厂publicFruitcreateFruit(){returnnewApple();}}publicclassGrapeFactoryimplementsFruitFactoy{//具体的工厂publicFruitcreateFruit(){returnnewGrape();}}publicclassStrawberryFactoryimplementsFruitFactoy{//具体的工厂publicFruitcreateFruit(){returnnewStr

7、awberry();}}publicclassTest{publicstaticvoidmain(String[]args){newAppleFactory().createFruit().grow();newGrapeFactory().createFruit().grow();newStrawberryFactory().createFruit().grow();}}随着市场和企业定位变化，决定只生产苹果、葡萄和草莓等少数果品，但每一果品呈系列化，如：普通水果、绿色水果等等，原设计模式不能很好地适应这种需要，需要改进设计模式。抽象工

8、厂模式农场分为两种：普通农场生产各种普通水果，绿色农场生产各种绿色水果。publicinterfaceFruit{//抽象的水果产品publicvoidgrow();}publicinterfaceFrui