public static LocalDateTime parseLocalDateTime19(String str, int off) {
        if (off + 19 > str.length()) {
            return null;
        }

        LocalDateTime ldt;
        if (STRING_CODER != null && STRING_VALUE != null && STRING_CODER.applyAsInt(str) == 0) {
            byte[] bytes = JDKUtils.STRING_VALUE.apply(str);
            ldt = parseLocalDateTime19(bytes, off);
        } else if (JVM_VERSION == 8 && !FIELD_STRING_VALUE_ERROR) {
            char[] chars = JDKUtils.getCharArray(str);
            ldt = parseLocalDateTime19(chars, off);
        } else {
            char[] chars = new char[19];
            str.getChars(off, off + 19, chars, 0);
            ldt = parseLocalDateTime19(chars, off);
        }
        return ldt;
    }
yyyy-MM-ddTHH:mm:ss
yyyy-MM-dd HH:mm:ss
yyyy/MM/ddTHH:mm:ss
yyyy/MM/dd HH:mm:ss
core/src/main/java/com/alibaba/fastjson2/util/DateUtils.java