取上个月正月时间段

        Calendar cal = Calendar.getInstance();
        int year = cal.get(Calendar.YEAR);
        int month = cal.get(Calendar.MONTH);
        cal.set(Calendar.DAY_OF_MONTH, 1);
        cal.add(Calendar.DAY_OF_MONTH, -1);
        int day = cal.get(Calendar.DAY_OF_MONTH);
        
        Result.setAttribute("startDate", year+"-"+month+"-01");
        Result.setAttribute("endDate", year+"-"+month+"-"+day);