String perfTimeStr = "";

// 统一设置日历格式

Calendar calendar = Calendar.getInstance();

calendar.setTime(new Date());

calendar.set(Calendar.DATE, 1);

calendar.set(Calendar.HOUR_OF_DAY, 0);

calendar.set(Calendar.MINUTE, 0);

calendar.set(Calendar.SECOND, 0);

// 时间戳存在用指定的，不存在使用当前日期

if(perfTime > 0){

Calendar calPerfTime = Calendar.getInstance();

calPerfTime.setTime(new Date(perfTime));

calendar.set(Calendar.YEAR,calPerfTime.get(Calendar.YEAR));

calendar.set(Calendar.MONTH, calPerfTime.get(Calendar.MONTH));

}

//获取时间戳，并转换成____-MM-01 00:00:00格式

DateFormat format = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");

perfTimeStr = format.format(calendar);

perfTimeStr = perfTimeStr.replace(perfTimeStr.substring(0,4), "____");

//获取时间戳，并转换成DATE类型,yyyy-MM-01 00:00:00格式

Date startTime = calendar.getTime();