java 中获取2个时间段中所包含的周数(股票的周数->从周六到周五)

Calendar 类中是以周日为开始的第一天的,所以Calendar.DAY_OF_WEEK为1的时候是周日.

在股票中有日K 周K和月K的数据. 

在此之中的周K是指交易日中一周的数据,周六到周五为一个周期.

 /**
      * 返回2个日期间有多少股票周
      * @param startDate 2012-02-01 开始日期
      * @param endDate  2014-02-01   结束日期
      * @return
      */
     public static  int getStockWeeks(String  startDate,String endDate){
         int a = 0;
         try {
             SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
             Calendar before = Calendar.getInstance();
             Calendar after = Calendar.getInstance();
             Calendar temp = Calendar.getInstance();

             before.setTime(sdf.parse(startDate));
             after.setTime(sdf.parse(endDate));

             long time1 = before.getTime().getTime();
             long time2 = after.getTime().getTime();

             if(time1>time2){//开始和结束时间对换了(有可能前后时间给错了)
                 temp=before;
                 before=after;
                 after=temp;
             }

             int week = before.get(Calendar.DAY_OF_WEEK);

             before.add(Calendar.DATE, -week);//并非周一为第一天  周六为第一天  

             week = after.get(Calendar.DAY_OF_WEEK);

             if(week>0&&week<7)after.add(Calendar.DATE, 6 - week);
             if(week==7)after.add(Calendar.DATE, 6);
             a= (int) ((after.getTimeInMillis() - before
                     .getTimeInMillis()) / CONST_WEEK);
             a = a - 1;
             if (a == 0) {
                 a = 1;
             }
         } catch (Exception e) {
             e.printStackTrace();
         }
         return a;
     }