code: public static long getTwoDaysBetweenNumber(String startDate, String endDate, Format format) {
          SimpleDateFormat localFormat = (SimpleDateFormat) format;
          long day = 0;
          try {
              java.util.Date startDay = localFormat.parse(startDate);
              java.util.Date endDay = localFormat.parse(endDate);
              day = (endDay.getTime() - startDay.getTime()) / (24 * 60 * 60 * 1000);
          } catch (Exception e) {
              return 0;
          }
          return day;
      }
docs: 指定fotmat,得到二个日期间的间隔天数
  
  @param startDate
  @param endDate
  @param format
  
  @return
  
  @author zhangbi