public final class LocalDateTimeUtils {

    /** * 日期格式yyyy-MM-dd */
    public static String DATE_PATTERN = "yyyy-MM-dd";

    /** * 日期时间格式yyyy-MM-dd HH:mm:ss */
    public static String DATE_TIME_PATTERN = "yyyy-MM-dd HH:mm:ss";

    /** * 构造函数 */
    private LocalDateTimeUtils() {
        super();
    }

    /** * Date转LocalDateTime * * @param date * Date对象 * @return */
    public static LocalDateTime dateToLocalDateTime(Date date) {
        return LocalDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault());
    }

    /** * LocalDateTime转换为Date * * @param dateTime * LocalDateTime对象 * @return */
    public static Date localDateTimeToDate(LocalDateTime dateTime) {
        return Date.from(dateTime.atZone(ZoneId.systemDefault()).toInstant());
    }

    /** * 格式化时间-默认yyyy-MM-dd HH:mm:ss格式 * * @param dateTime * LocalDateTime对象 * @return */
    public static String formatDateTime(LocalDateTime dateTime) {
        return formatDateTime(dateTime, DATE_TIME_PATTERN);
    }

    /** * 按pattern格式化时间-默认yyyy-MM-dd HH:mm:ss格式 * * @param dateTime * LocalDateTime对象 * @param pattern * 要格式化的字符串 * @return */
    public static String formatDateTime(LocalDateTime dateTime, String pattern) {
        if (dateTime == null) {
            return null;
        }
        if (pattern == null || pattern.isEmpty()) {
            pattern = DATE_TIME_PATTERN;
        }
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern(pattern);
        return dateTime.format(formatter);
    }

    /** * 获取今天的00:00:00 * * @return */
    public static String getDayStart() {
        return getDayStart(LocalDateTime.now());
    }

    /** * 获取今天的23:59:59 * * @return */
    public static String getDayEnd() {
        return getDayEnd(LocalDateTime.now());
    }

    /** * 获取某天的00:00:00 * * @param dateTime * @return */
    public static String getDayStart(LocalDateTime dateTime) {
        return formatDateTime(dateTime.with(LocalTime.MIN));
    }

    /** * 获取某天的23:59:59 * * @param dateTime * @return */
    public static String getDayEnd(LocalDateTime dateTime) {
        return formatDateTime(dateTime.with(LocalTime.MAX));
    }

    /** * 获取本月第一天的00:00:00 * * @return */
    public static String getFirstDayOfMonth() {
        return getFirstDayOfMonth(LocalDateTime.now());
    }

    /** * 获取本月最后一天的23:59:59 * * @return */
    public static String getLastDayOfMonth() {
        return getLastDayOfMonth(LocalDateTime.now());
    }

    /** * 获取某月第一天的00:00:00 * * @param dateTime * LocalDateTime对象 * @return */
    public static String getFirstDayOfMonth(LocalDateTime dateTime) {
        return formatDateTime(dateTime.with(TemporalAdjusters.firstDayOfMonth()).with(LocalTime.MIN));
    }

    /** * 获取某月最后一天的23:59:59 * * @param dateTime * LocalDateTime对象 * @return */
    public static String getLastDayOfMonth(LocalDateTime dateTime) {
        return formatDateTime(dateTime.with(TemporalAdjusters.lastDayOfMonth()).with(LocalTime.MAX));
    }

    /** * 测试 * * @param args */
    public static void main(String[] args) {
        System.out.println(getDayStart());
        System.out.println(getDayEnd());
        System.out.println(getFirstDayOfMonth());
        System.out.println(getLastDayOfMonth());
    }

}