试题五(共15分)阅读以下说明和Java程序，填补代码中的空缺，将解答填入答题纸的对应栏内。【说明】以下Jave代码实现一个简单客户关系管理系统(CrM)中通过工厂(Customerrfactory)对象来创建客户(Customer)对象的功能。客户分为创建成功的客户(realCustomer)和空客户(NullCustomer)。空客户对象是当不满足特定条件时创建或获取的对象。类间关系如图5-1所示。【Java代码】AbstractclassCustomer﹛ProtectedStringname;()booleanisNil()()StringgetName();﹜ClassrealCustomer()Customer﹛PublicrealCustomer(Stringname)﹛returnfalse;﹜﹜ClassNullCustomer()Customer﹛PublicStringgetName()﹛return″NotAvailableinCustomerDatabase″;﹜PublicbooleanisNil()﹛returntrue;﹜﹜classCustomerfactory{publicString[]names={"rob"，"Joe"，"Julie"};publicCustomergetCustomer(Stringname){for(inti=0;i＜names.length;i++){if(names[i].())﹛returnnewrealCusωmer(name);﹜﹜return()﹜﹜PublicclassCrM﹛PublicviodgetCustomer()﹛Customerfactory()Customercustomer1-cf.getCustomer(″rob″);Customercustomer2=cf.getCustomer(″rob″);Customercustomer3=cf.getCustomer(″Julie″);Customercustomer4=cf.getCustomer(″Laura″);System.out.println(″customer1.getName());System.out.println(″customer2getName());System.out.println(″customer3.getName());System.out.println(″customer4.getName());﹜Publicstaticviodmain(String[]arge)﹛CrMcrm=newCrM();Crm,getCustomer();﹜﹜／*程序输出为：CustomerrobNotAvailableinCustomerDatabaseJulieNotAvailableinCustomerDatable*／intmain()﹛CrM*crs=newCrM();Crs->getCustomer();Crs->getCustomer();Deletecrs;return();﹜／*程序输出为：CustomerrobNotAvailableiniCustomerDatabaseJulieNotAvailableinCustomerDatabase
1）public abstract2) public abstract3)extends4)extends5)equals(name)6)new Null Customer()7) cf=New CustomerFactory(); 【解析】 本题考察Java程序设计客户关系管理系统。1)public abstract 定义可访问方法2) public abstract3)extends 继承Customer类4)extends5)equals(name) 判断名字是否在数组集合内6)new Null Customer() 当不满足条件时创建一个空对象7) cf=New CustomerFactory(); 实例化对象cf
