黑马程序员_面试题_对银行业务调度系统总结

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1.         首先我们要先建立一个号码管理器；

里面有取号动作(获取号码的动作)，和存储号码的动作；

这时就会用到集合，通过集合的方式将取出来的号码进行存储；

//      产生客户号码；并且加到集合中；

         public synchronized Integer generateNewNumber(){

                   queueNumbers.add(++lastNumber);

                   return lastNumber;

         }

//      取到我们最先添加进去的客户号码；

         public synchronized Integer fetchNumber(){

                   if(queueNumbers.size()>0){

                            return (Integer)queueNumbers.remove(0);

                   }else{

                            return null;

                   }

         }

                                         

因为它queueNumbers.remove(0)的返回类型是元素，所以;就具有获取集合中的元素功能。

2.         我们要设计一个单例模式，从一个机器上取出三类号码；通过三类号码来获取集合中的元素，也可以在集合中产生元素；

3.         通过枚举类来获取对象的名称；

public enum CustomerType {

                       COMMON,EXPRESS,VIP;

                       public String toString(){

                            String name = null;

                            switch(this){

                            case COMMON:

                                     name = "普通";

                                     break;

                            case EXPRESS:

                                     name = "快速";

                                     break;

                            case VIP:

//                                  枚举常量的名称，这里返回就是vip

                                     name = name();

                                     break;

                            }

                            return name;

                       }

}

4.         每产生一个窗口，我们都会启动开启窗口的线程；

public void start(){

建立一个线程；执行只有一个参数，这里面就是线程；

                                          Executors.newSingleThreadExecutor().execute(

                                               new Runnable(){

                                                        public void run(){

                                          //下面这种写法的运行效率低，最好是把while放case下面

                                                                 while(true){

                                                                           switch(type){

                                                                                    case COMMON:

                                                                                             commonService();

                                                                                             break;

                                                                                    case EXPRESS:

                                                                                             expressService();

                                                                                             break;

                                                                                    case VIP:

                                                                                             vipService();

                                                                                             break;

                                                                           }

                                                                 }

                                                        }

                                               }

                                     );

5.         线程里面的执行方法解析；

private void commonService(){

默认的是第1号，普通窗口；type的值，就是枚举里面的ToString里面的值；

String windowName = "第" + number + "号" + type + "窗口";      

System.out.println(windowName + "开始获取普通任务!");

产生对象获取号码；

Integer serviceNumber = NumberMachine.getInstance()

.getCommonManager().fetchNumber();        

if(serviceNumber != null ){

System.out.println(windowName + "开始为第" + serviceNumber + "号普通客户服务");

获取serviceTime时间；serviceTime是0到10秒之间随机产生；

int maxRandom = Constants.MAX_SERVICE_TIME - Constants.MIN_SERVICE_TIME;

int serviceTime = new Random().nextInt(maxRandom)+1 + Constants.MIN_SERVICE_TIME;

                                     try {

                                               Thread.sleep(serviceTime);

                                     } catch (InterruptedException e) {

                                               e.printStackTrace();

                                     }       

System.out.println(windowName + "完成为第" + serviceNumber +

              "号普通客户服务，总共耗时" + serviceTime/1000 + "秒");

//获取到的号码要是为空的话；                   

}else{

System.out.println(windowName + "没有取到普通任务，正在空闲一秒");              

                                     try {

                                               Thread.sleep(1000);

                                     } catch (InterruptedException e) {

                                               e.printStackTrace();

                                     }                                   

                            }

                                 }

6.         客户拿到号码代码解析

//普通客户拿号

Executors.newScheduledThreadPool(1).scheduleAtFixedRate(

                                          new Runnable(){

                       public void run(){

//从机器中产生一个号码；

Integer serviceNumber = NumberMachine.getInstance().

getCommonManager().generateNewNumber();

//拿到号码；

System.out.println("第" + serviceNumber + "号普通客户正在等待服务！");                      

                   }

                   },

                0,

Constants.COMMON_CUSTOMER_INTERVAL_TIME,

TimeUnit.SECONDS);

7.         银行系统里面用到的知识点总结；

1、集合；

2、同步代码块；

3、单例模式；

4、枚举类

5、1.5的新特性线程池；包括定时线程，和不定时线程两种；