java.util.Calendar获取时间区间问题

虽然java8的LocalDate已经出来,但是很多项目以及自己习惯上还是使用Date,这里还是简单介绍一下如何通过java.util.Calendar获取时间区间.

1 通过calendar.getActualMinimum,getActualMaximum获取周,月,年的最大值,最小值

     /**
      * @Title: getSeasonFrist
      * @Description: 获取季度初日期
      * @param calendar
      * @return
      * @throws ParseException
      */
     public static String getSeasonFrist(Calendar calendar) throws ParseException {
         int month = calendar.get(Calendar.MONTH);
         int season = getSeason(month, 0);
         calendar.set(Calendar.DAY_OF_MONTH, 0);
         calendar.set(Calendar.MONTH, season);
         calendar.add(Calendar.DATE, calendar.getActualMinimum(Calendar.DAY_OF_MONTH));
         return sdf.format(calendar.getTime());
     }

     /**
      * @Title: getSeasonLast
      * @Description: 获取季度末日期时间
      * @param calendar
      * @return
      * @throws ParseException
      */
     public static String getSeasonLast(Calendar calendar) throws ParseException {
         int month = calendar.get(Calendar.MONTH);
         int season = getSeason(month, 1);
         calendar.set(Calendar.MONTH, season);
         calendar.set(Calendar.DAY_OF_MONTH, -1);
         calendar.add(Calendar.DATE, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
         return sdf.format(calendar.getTime());
     }

问题,因为直接设置月份,除了月份其他信息没有改,会造成获取月份最大值不准确,即当前月是9月,我把月份改成10,但是9月的最大天数是30,所以获取月份最后一天就是:10月30日

方式二:通过获取下月月初减一的方式获取区间最后一天,这种方式可简单有效解决月末日期不准确问题

     /**
      * @Title: getSeasonFrist
      * @Description: 获取季度初日期
      * @param calendar
      * @return
      * @throws ParseException
      */
     public static String getSeasonFrist(Calendar calendar) throws ParseException {
         int month = calendar.get(Calendar.MONTH);
         int season = getSeason(month, 0);
         calendar.set(Calendar.MONTH, season);
         calendar.set(Calendar.DAY_OF_MONTH, 1);
         return sdf.format(calendar.getTime());
     }

     /**
      * @Title: getSeasonLast
      * @Description: 获取季度末日期时间
      * @param calendar
      * @return
      * @throws ParseException
      */
     public static String getSeasonLast(Calendar calendar) throws ParseException {
         int month = calendar.get(Calendar.MONTH);
         int season = getSeason(month, 1);
         calendar.set(Calendar.MONTH, season + 1);
         calendar.set(Calendar.DAY_OF_MONTH, 0);
         return sdf.format(calendar.getTime());
     }

这里用季度的例子举例,月和年类似;因为calendar没有直接获取季度的方法,季度的区间需要自己定义,其实就是获取当前月,然后自己定义每个月属于哪个季度,并返回季度首尾的月份;