public class SmsEntity{  private Integer id;  private String mobile;  private String ip;  private Integer type;  private Date time;  private String captcha;  // 省略構(gòu)造方法和getter、setter方法}

public interface SmsFilter {  /**   * 初始化該過濾器   */  void init() throws Exception;  /**   * 判斷短信是否可以發(fā)送.   * @param smsEntity 將要發(fā)送的短信內(nèi)容   * @return 可以發(fā)送則返回true, 否則返回false   */  boolean filter(SmsEntity smsEntity);  /**   * 銷毀該過濾器   */  void destroy();}

public class FrequencyFilter implements SmsFilter {  /**   * 發(fā)送間隔, 單位: 毫秒   */  private long sendInterval;  private ConcurrentMap<String, Long> sendAddressMap = new ConcurrentHashMap<>();  // 省略了部分無用代碼  @Override  public boolean filter(SmsEntity smsEntity) {    if(setSendTime(smsEntity.getMobile()) && setSendTime(smsEntity.getIp())){      return true;    }    return false;  }  /**   * 將發(fā)送時(shí)間修改為當(dāng)前時(shí)間.   * 如果距離上次發(fā)送的時(shí)間間隔大于{@link #sendInterval}則設(shè)置發(fā)送時(shí)間為當(dāng)前時(shí)間. 否則不修改任何內(nèi)容.   *   * @param id 發(fā)送手機(jī)號(hào) 或 ip   * @return 如果成功將發(fā)送時(shí)間修改為當(dāng)前時(shí)間, 則返回true. 否則返回false   */  private boolean setSendTime(String id) {    long currentTime = System.currentTimeMillis();    Long sendTime = sendAddressMap.putIfAbsent(id, currentTime);    if(sendTime == null) {      return true;    }    long nextCanSendTime = sendTime + sendInterval;    if(currentTime < nextCanSendTime) {      return false;    }    return sendAddressMap.replace(id, sendTime, currentTime);  }}

/** * 在上面代碼的基礎(chǔ)上, 再添加如下代碼 */public class FrequencyFilter implements SmsFilter {  private long cleanMapInterval;  private Timer timer = new Timer("sms_frequency_filter_clear_data_thread");  @Override  public void init() {    timer.schedule(new TimerTask() {      @Override      public void run() {        cleanSendAddressMap();      }    }, cleanMapInterval, cleanMapInterval);  }  /**   * 將sendAddressMap中的所有過期數(shù)據(jù)刪除   */  private void cleanSendAddressMap() {    long currentTime = System.currentTimeMillis();    long expireSendTime = currentTime - sendInterval;    for(String key : sendAddressMap.keySet()) {      Long sendTime = sendAddressMap.get(key);      if(sendTime < expireSendTime) {        sendAddressMap.remove(key, sendTime);      }    }  }  @Override  public void destroy() {    timer.cancel();  }}

private boolean setSendTime(String id) {  // 省略前面的代碼  if(sendAddressMap.replace(id, sendTime, currentTime)) {    return true;  }  return sendAddressMap.putIfAbsent(id, currentTime) == null;}

public class SmsService{  private Sms sms;  private List<SmsFilter> filters;  private Properties template;  // 省略了部分代碼  /**   * 發(fā)送驗(yàn)證碼   *   * @param smsEntity 發(fā)送短信的基本數(shù)據(jù)   * @return 如果提交成功, 返回0. 否則返回其他值.   */  public int sendCaptcha(SmsEntity smsEntity){    for(SmsFilter filter : filters) {      if(!filter.filter(smsEntity)){        return 1;      }    }    if(SmsEntity.REGISTER_TYPE.equals(smsEntity.getType())) {      sendRegisterSms(smsEntity);    }    else{      return 2;    }    return 0;  }  /**   * 發(fā)送注冊(cè)驗(yàn)證碼   *   * @param smsEntity 發(fā)送短信的基本數(shù)據(jù)   */  private void sendRegisterSms(SmsEntity smsEntity) {    sms.sendMessage(smsEntity.getMobile(),        template.getProperty("register").replace("{captcha}", smsEntity.getCaptcha()));  }}