java匹配字符串中指定格式的时间并返回

public final class StrMatchUtil {

    private static final Logger logger = LoggerFactory.getLogger(StrMatchUtil.class);

    
    public static LocalDateTime getDateTimeFromStr(String str){
        final String pattern = "\d{4}-\d{2}-\d{2}";
        Pattern r = Pattern.compile(pattern);
        Matcher m = r.matcher(str);
        String st;
        if (m.find()) {
            st = m.group();
        } else {
            logger.error(ResultEnum.DATE_TIME_PARSE_ERROR.getMsg());
            return null;
        }
        try {
            return DateTimeUtil.Str2LocalDateTime(st, "yyyy-MM-dd");
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return null;
    }

}

public class DateTimeUtil {


    
    public static String LocalDateTime2Str(LocalDateTime localDateTime,String timeFormatter){
        DateTimeFormatter dtf = DateTimeFormatter.ofPattern(timeFormatter);
        return dtf.format(localDateTime);
    }

    
    public static LocalDateTime Str2LocalDateTime(String localDateTime, String timeFormatter) throws ParseException {
        SimpleDateFormat fmt = new SimpleDateFormat(timeFormatter);
        Date date = fmt.parse(localDateTime);
        return LocalDateTime.ofInstant(date.toInstant(), ZoneOffset.of("+8"));
    }

    
    public static LocalDateTime genCurrentDayBegin(LocalDateTime localDateTime) throws ParseException {
        String time = LocalDateTime2Str(localDateTime, "yy-MM-dd") + " 00:00:00";
        return Str2LocalDateTime(time, "yy-MM-dd hh:mm:ss");
    }


    
    public static LocalDateTime genCurrentDayEnd(LocalDateTime localDateTime) throws ParseException {
        String time = LocalDateTime2Str(localDateTime, "yy-MM-dd") + " 23:59:59";
        return Str2LocalDateTime(time, "yy-MM-dd hh:mm:ss");
    }

}