重构到设计模式的经典案例，超完美详细（java源码）

package com.chinanetcenter.example.charge.version6; import java.net.URL; import java.util.*; public class User { private String name; private Vector<Bill> bills = new Vector<Bill>(); public User(String name) { this.name = name; } public void addBill(Bill bill) { this.bills.addElement(bill); } public String getName() { return this.name; } public String report() { Enumeration<Bill> bills = this.bills.elements(); String result = getName() + "被收取的服务费用：\n"; while (bills.hasMoreElements()) { Bill bill = (Bill) bills.nextElement(); result += "\t" + bill.getService().getAddress() + "\t" + String.valueOf(bill.getCharge()) + "\n"; } result += "\n\t收费总额是\t" + String.valueOf(getTotalCharge()) + "元\n"; result += "\t重要性指数\t" + String.valueOf(getTotalAbility()) + "\n"; return result; } private int getTotalAbility() { int totalAbility = 0; Enumeration<Bill> bills = this.bills.elements(); while (bills.hasMoreElements()) { Bill bill = (Bill) bills.nextElement(); totalAbility += bill.getAbility(); } return totalAbility; } private double getTotalCharge() { double totalCharge = 0; Enumeration<Bill> bills = this.bills.elements(); while (bills.hasMoreElements()) { Bill bill = (Bill) bills.nextElement(); totalCharge += bill.getCharge(); } return totalCharge; } } class Bill { private Service service; private double trafficAccount; public Bill(Service service, double trafficAccount) { this.service = service; this.trafficAccount = trafficAccount; } public double getTrafficAccount() { return trafficAccount; } public void setTrafficAccount(double trafficAccount) { this.trafficAccount = trafficAccount; } public Service getService() { return this.service; } public int getAbility() { return service.getAbility(getTrafficAccount()); } public double getCharge() { return service.getCharge(getTrafficAccount()); } } class Service { private URL address; private ServiceType type; public Service(URL address,int type) { this.address = address; this.setType(ServiceType.getServiceType(type)); } public ServiceType getType() { return this.type; } public void setType(ServiceType type) { this.type = type; } public URL getAddress() { return address; } public void setAddress(URL address) { this.address = address; } public int getAbility(double trafficAccount) { return getType().getAbility(trafficAccount); } public double getCharge(double trafficAccount) { return getType().getCharge(trafficAccount); } } abstract class ServiceType { public static final int WEB = 0; public static final int STREAM = 1; public static final int DOWNLOAD = 2; abstract int getTypeCode(); abstract double getCharge(double trafficAccount); abstract int getAbility(double trafficAccount); public static ServiceType getServiceType(int code) { switch (code) { case ServiceType.WEB: return new Web(); case ServiceType.STREAM: return new Stream(); case ServiceType.DOWNLOAD: return new Download(); default: throw new IllegalArgumentException("不存在的类型"); } } } class Web extends ServiceType { public Web() { } @Override public int getTypeCode() { return ServiceType.WEB; } @Override public double getCharge(double trafficAccount) { return trafficAccount * 1000; } @Override public int getAbility(double trafficAccount) { return (int)trafficAccount/100; } } class Stream extends ServiceType { public Stream() { } @Override public int getTypeCode() { return ServiceType.STREAM; } @Override public double getCharge(double trafficAccount) { return trafficAccount * 0.7 * 1000; } @Override int getAbility(double trafficAccount) { return (int)trafficAccount/600; } } class Download extends ServiceType { public Download() { } @Override public int getTypeCode() { return ServiceType.DOWNLOAD; } @Override public double getCharge(double trafficAccount) { return trafficAccount * 0.5 * 1000; } @Override int getAbility(double trafficAccount) { return (int)trafficAccount/600; } }