Quartz.Net系列（九）：Trigger之CronScheduleBuilder和Cron表达式详解

            var scheduler =await StdSchedulerFactory.GetDefaultScheduler();

            await scheduler.Start();

            var job = JobBuilder.Create<FirstJob>().Build();

            var trigger = TriggerBuilder.Create().WithCronSchedule("* * * * * ?").Build();

            await scheduler.ScheduleJob(job, trigger);

        public static TriggerBuilder WithCronSchedule(this TriggerBuilder triggerBuilder, string cronExpression)
        {
            CronScheduleBuilder builder = CronScheduleBuilder.CronSchedule(cronExpression);
            return triggerBuilder.WithSchedule(builder);
        }

 protected virtual int StoreExpressionVals(int pos, string s, int type)
        {
            int incr = 0;
            int i = SkipWhiteSpace(pos, s);
            if (i >= s.Length)
            {
                return i;
            }
            char c = s[i];
            if (c >= ‘A‘ && c <= ‘Z‘ && !s.Equals("L") && !s.Equals("LW") && !regex.IsMatch(s))
            {
                string sub = s.Substring(i, 3);
                int sval;
                int eval = -1;
                if (type == Month)
                {
                    sval = GetMonthNumber(sub) + 1;
                    if (sval <= 0)
                    {
                        throw new FormatException($"Invalid Month value: ‘{sub}‘");
                    }
                    if (s.Length > i + 3)
                    {
                        c = s[i + 3];
                        if (c == ‘-‘)
                        {
                            i += 4;
                            sub = s.Substring(i, 3);
                            eval = GetMonthNumber(sub) + 1;
                            if (eval <= 0)
                            {
                                throw new FormatException(
                                    $"Invalid Month value: ‘{sub}‘");
                            }
                        }
                    }
                }
                else if (type == DayOfWeek)
                {
                    sval = GetDayOfWeekNumber(sub);
                    if (sval < 0)
                    {
                        throw new FormatException($"Invalid Day-of-Week value: ‘{sub}‘");
                    }
                    if (s.Length > i + 3)
                    {
                        c = s[i + 3];
                        if (c == ‘-‘)
                        {
                            i += 4;
                            sub = s.Substring(i, 3);
                            eval = GetDayOfWeekNumber(sub);
                            if (eval < 0)
                            {
                                throw new FormatException(
                                    $"Invalid Day-of-Week value: ‘{sub}‘");
                            }
                        }
                        else if (c == ‘#‘)
                        {
                            try
                            {
                                i += 4;
                                nthdayOfWeek = Convert.ToInt32(s.Substring(i), CultureInfo.InvariantCulture);
                                if (nthdayOfWeek < 1 || nthdayOfWeek > 5)
                                {
                                    throw new Exception();
                                }
                            }
                            catch (Exception)
                            {
                                throw new FormatException(
                                    "A numeric value between 1 and 5 must follow the ‘#‘ option");
                            }
                        }
                        else if (c == ‘/‘)
                        {
                            try
                            {
                                i += 4;
                                everyNthWeek = Convert.ToInt32(s.Substring(i), CultureInfo.InvariantCulture);
                                if (everyNthWeek < 1 || everyNthWeek > 5)
                                {
                                    throw new Exception();
                                }
                            }
                            catch (Exception)
                            {
                                throw new FormatException(
                                    "A numeric value between 1 and 5 must follow the ‘/‘ option");
                            }
                        }
                        else if (c == ‘L‘)
                        {
                            lastdayOfWeek = true;
                            i++;
                        }
                        else
                        {
                            throw new FormatException($"Illegal characters for this position: ‘{sub}‘");
                        }
                    }
                }
                else
                {
                    throw new FormatException($"Illegal characters for this position: ‘{sub}‘");
                }
                if (eval != -1)
                {
                    incr = 1;
                }
                AddToSet(sval, eval, incr, type);
                return i + 3;
            }

            if (c == ‘?‘)
            {
                i++;
                if (i + 1 < s.Length && s[i] != ‘ ‘ && s[i + 1] != ‘\t‘)
                {
                    throw new FormatException("Illegal character after ‘?‘: "
                                              + s[i]);
                }
                if (type != DayOfWeek && type != DayOfMonth)
                {
                    throw new FormatException(
                        "‘?‘ can only be specified for Day-of-Month or Day-of-Week.");
                }
                if (type == DayOfWeek && !lastdayOfMonth)
                {
                    int val = daysOfMonth.LastOrDefault();
                    if (val == NoSpecInt)
                    {
                        throw new FormatException(
                            "‘?‘ can only be specified for Day-of-Month -OR- Day-of-Week.");
                    }
                }

                AddToSet(NoSpecInt, -1, 0, type);
                return i;
            }

            var startsWithAsterisk = c == ‘*‘;
            if (startsWithAsterisk || c == ‘/‘)
            {
                if (startsWithAsterisk && i + 1 >= s.Length)
                {
                    AddToSet(AllSpecInt, -1, incr, type);
                    return i + 1;
                }
                if (c == ‘/‘ && (i + 1 >= s.Length || s[i + 1] == ‘ ‘ || s[i + 1] == ‘\t‘))
                {
                    throw new FormatException("‘/‘ must be followed by an integer.");
                }
                if (startsWithAsterisk)
                {
                    i++;
                }
                c = s[i];
                if (c == ‘/‘)
                {
                    // is an increment specified?
                    i++;
                    if (i >= s.Length)
                    {
                        throw new FormatException("Unexpected end of string.");
                    }

                    incr = GetNumericValue(s, i);

                    i++;
                    if (incr > 10)
                    {
                        i++;
                    }
                    CheckIncrementRange(incr, type);
                }
                else
                {
                    if (startsWithAsterisk)
                    {
                        // invalid value s
                        throw new FormatException("Illegal characters after asterisk: " + s);
                    }
                    incr = 1;
                }

                AddToSet(AllSpecInt, -1, incr, type);
                return i;
            }
            if (c == ‘L‘)
            {
                i++;
                if (type == DayOfMonth)
                {
                    lastdayOfMonth = true;
                }
                if (type == DayOfWeek)
                {
                    AddToSet(7, 7, 0, type);
                }
                if (type == DayOfMonth && s.Length > i)
                {
                    c = s[i];
                    if (c == ‘-‘)
                    {
                        ValueSet vs = GetValue(0, s, i + 1);
                        lastdayOffset = vs.theValue;
                        if (lastdayOffset > 30)
                        {
                            throw new FormatException("Offset from last day must be <= 30");
                        }
                        i = vs.pos;
                    }
                    if (s.Length > i)
                    {
                        c = s[i];
                        if (c == ‘W‘)
                        {
                            nearestWeekday = true;
                            i++;
                        }
                    }
                }
                return i;
            }
            if (c >= ‘0‘ && c <= ‘9‘)
            {
                int val = Convert.ToInt32(c.ToString(), CultureInfo.InvariantCulture);
                i++;
                if (i >= s.Length)
                {
                    AddToSet(val, -1, -1, type);
                }
                else
                {
                    c = s[i];
                    if (c >= ‘0‘ && c <= ‘9‘)
                    {
                        ValueSet vs = GetValue(val, s, i);
                        val = vs.theValue;
                        i = vs.pos;
                    }
                    i = CheckNext(i, s, val, type);
                    return i;
                }
            }
            else
            {
                throw new FormatException($"Unexpected character: {c}");
            }

            return i;
        }