一篇带你了解建造者模式的文章

本文转载自微信公众号《好困》，作者萌新。转载此文，好困烦请联系我公众号。构建器模式：从多个简单对象按特定顺序逐步创建一个复杂对象。旨在将复杂对象的构造与其表示分离。主要解决方案主要是解决“复杂对象”的构造和组合。这个“复杂对象”是由多个子对象按照一定的规则组合而成的。关键代码生成器：组装多个子对象。使用场景复杂对象由多个子对象组成。代码实现了代码的主要功能：定义两个子对象cat和dog，通过builder将这两个子对象组装成对应的复杂对象pet。1.定义各种“商品”构建抽象商品接口1/**2*抽象商品接口3*/4publicinterfaceItem{56//商品名称7publicStringname();8//商品价格9publicFloatprice();10//默认行为11publicStringcanDO();12}构造“猫”产品1/**2*猫产品抽象类3*提供猫默认行为4*/5publicabstractclassCatimplementsItem{67publicStringcanDO(){8return"miaomiao....";9}0}bigCat1/**2*bigcat3*/4publicclassBigCattextendsCat{5@Override6publicStringname(){7return"bigcat";8}910@Override11publicFloatprice(){12return500.0f;13}14}smallCat1publicclassSmallCattextendsCat{2@Override3publicsmallStringname()}67@Override8publicFloatprice(){9return100.0f;10}11}构造“狗”产品1/**2*狗产品抽象类3*提供狗默认行为4*/5publicabstractclassDogiimplementsItem{67publicStringcanDO(){8return"wangwang....";9}0}bigDog1/**2*bigdog3*/4publicclassBigDogextendsDog{5@Override6publicStringname(){7return"bigdog";8}910@Override11publicFloatprice(){12return1000.0f;13}14}SmallDog1/**2*smalldog3*/4publicclassSmallDogextendsDog{5@Override6publicStringname(){7return"smalldog";8}910@Override11publicFloatprice(){12return200.0f;13}14}2.定义抽象“package”，构建“pet”包1/**2*pet3*/4publicclassPet{56privateListlist=newArrayList<>();78//添加物品9publicvoidaddItem(Itemitem){10list.add(item);11}1213//获取选中宠物的价格14publicfloatgetCost(){15floatcost=0.0f;16for(Itemititem:list){17cost+=item.price();18}19returncost;20}2122publicvoidshowPet(){23for(Itemitem:list){24System.out.print("Item:"+item.name());25System.out.print(",speak:"+item.canDO());26System.out.println(",Price:"+item.price());27}28}2930}3。定义builder将“产品”按照特定的顺序构造成特定的“包”Buildcreators，创建对应的“包”1/**2*Builder:3*将已有的产品按照特性的顺序组装成特定的“包”4*/5publicclassPetBuilder{67//组装大宠物套装8publicPetbuildBigPet(){9Petpet=newPet();10pet.addItem(newBigCat());11pet.addItem(newBigDog());12returnpet;13}1415//组装小宠物套装16publicPetbuildSmallPet(){17Petpet=newPet();18pet.addItem(newSmallDog());19pet.addItem(newSmallCat());20回宠物；21}2223}Tests:1/**2*TestBuilderMode3*/4publicclassMain{56publicstaticvoidmain(String[]args){7PetBuilderpetBuilder=newPetBuilder();8//调用builder构建Bigsuit9PetbigPet=petBuilder.buildBigPet();10System.out.println("Bigpet....");11bigPet.showPet();12System.out.println("Totalcost:"+bigPet.getCost());1314//调用builder构建小型套装15PetsmallPet=petBuilder.buildSmallPet();16System.out.println("Smallpet....");17smallPet.showPet();18System.out。println("Totalcost:"+smallPet.getCost());19}20}注：与工厂模式不同的是建造者模式更注重零件组装的顺序