/**

     * 获取当前月第一天

     * @param month

     * @return

     */

    public static String getFirstDayOfMonth(int month) {

        Calendar calendar = Calendar.getInstance();

        // 设置月份

        calendar.set(Calendar.MONTH, month - 1);

        // 获取某月最小天数

        int firstDay = calendar.getActualMinimum(Calendar.DAY_OF_MONTH);

        // 设置日历中月份的最小天数

        calendar.set(Calendar.DAY_OF_MONTH, firstDay);

        // 格式化日期

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

        String firstDay = sdf.format(calendar.getTime())+" 00:00:00";

        return firstDay;

    }

public static String getLastDayOfMonth(int month) {

        Calendar calendar = Calendar.getInstance();

        // 设置月份

        calendar.set(Calendar.MONTH, month - 1);

        // 获取某月最大天数

        int lastDay=0;

        //2月的平年瑞年天数

        if(month==2) {

            lastDay = calendar.getLeastMaximum(Calendar.DAY_OF_MONTH);

        }else {

            lastDay = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);

        }

        // 设置日历中月份的最大天数

        calendar.set(Calendar.DAY_OF_MONTH, lastDay);

        // 格式化日期

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

        String lastDay = sdf.format(calendar.getTime())+" 23:59:59";

        return lastDay;

    }