C#/.NET 解析Cron表达式,根据Cron表达式获取最近执行时间

Cron表达式定义及详情

请参考https://blog.csdn.net/HybridTheory_/article/details/88382442

使用C#解析Cron表达式，得到执行时间

class Cron
{
    private int[] seconds = new int[60];
    private int[] minutes = new int[60];
    private int[] hours = new int[24];
    private int[] days = new int[31];
    private int[] month = new int[12];
    private int[] weeks = new int[7];
    //2019-2099年
    private int[] year = new int[80];

    public int[] Seconds { get => seconds; set => seconds = value; }
    public int[] Minutes { get => minutes; set => minutes = value; }
    public int[] Hours { get => hours; set => hours = value; }
    public int[] Days { get => days; set => days = value; }
    public int[] Month { get => month; set => month = value; }
    public int[] Weeks { get => weeks; set => weeks = value; }
    public int[] Year { get => year; set => year = value; }

    public Cron()
    {
        for (int i = 0; i < 60; i++)
        {
            seconds[i] = 0;
            minutes[i] = 0;
        }
        for (int i = 0; i < 24; i++)
        {
            hours[i] = 0;
        }
        for (int i = 0; i < 31; i++)
        {
            days[i] = 0;
        }
        for (int i = 0; i < 12; i++)
        {
            month[i] = 0;
        }
        for (int i = 0; i < 7; i++)
        {
            weeks[i] = 0;
        }
        for (int i = 0; i < 80; i++)
        {
            year[i] = 0;
        }
    }

    public void Init()
    {
        for (int i = 0; i < 7; i++)
        {
            weeks[i] = 0;
        }
        for (int i = 0; i < 31; i++)
        {
            days[i] = 0;
        }
    }
}

/// 

/// 在week上使用  5L表示本月最后一个星期五
///               7L表示本月最后一个星期天
///               
/// 在week上使用  7#3表示每月的第三个星期天
///               2#4表示每月的第四个星期二
/// 
public class CronHelp
{
    /// 

    /// Cron表达式转换(默认开始时间为当前)
    /// 
    /// 表达式
    /// 最近5次要执行的时间
    private static List<DateTime> CronToDateTime(string cron)
    {
        try
        {
            List<DateTime> lits = new List<DateTime>();
            Cron c = new Cron();
            string[] arr = cron.Split(' ');
            Seconds(c, arr[0]);
            Minutes(c, arr[1]);
            Hours(c, arr[2]);
            Month(c, arr[4]);
            if (arr.Length < 7)
            {
                Year(c, null);
            }
            else
            {
                Year(c, arr[6]);
            }
            DateTime now = DateTime.Now;
            int addtime = 1;
            while (true)
            {
                if (c.Seconds[now.Second] == 1 && c.Minutes[now.Minute] == 1 && c.Hours[now.Hour] == 1 && c.Month[now.Month - 1] == 1 && c.Year[now.Year - 2019] == 1)
                {
                    if (arr[3] != "?")
                    {
                        Days(c, arr[3], DateTime.DaysInMonth(now.Year, now.Month), now);
                        int DayOfWeek = (((int)now.DayOfWeek) + 6) % 7;
                        if (c.Days[now.Day - 1] == 1 && c.Weeks[DayOfWeek] == 1)
                        {
                            lits.Add(now);
                        }
                    }
                    else
                    {
                        Weeks(c, arr[5], DateTime.DaysInMonth(now.Year, now.Month), now);
                        int DayOfWeek = (((int)now.DayOfWeek) + 6) % 7;
                        if (c.Days[now.Day - 1] == 1 && c.Weeks[DayOfWeek] == 1)
                        {
                            lits.Add(now);
                        }
                    }
                }
                if (lits.Count >= 5)
                {
                    break;
                }
                c.Init();
                if (!arr[1].Contains('-') && !arr[1].Contains(',') && !arr[1].Contains('*') && !arr[1].Contains('/'))
                {
                    if (now.Minute == int.Parse(arr[1]))
                    {
                        addtime = 3600;
                    }
                }
                else if (arr[0] == "0" && now.Second == 0)
                {
                    addtime = 60;
                }
                now = now.AddSeconds(addtime);
            }
            return lits;
        }
        catch
        {
            return null;
        }
    }

    /// 

    /// Cron表达式转换（自定义开始时间）
    /// 
    /// 表达式
    /// 开始时间
    /// 最近5次要执行的时间
    private static List<DateTime> CronToDateTime(string cron, DateTime now)
    {
        try
        {
            List<DateTime> lits = new List<DateTime>();
            Cron c = new Cron();
            string[] arr = cron.Split(' ');
            Seconds(c, arr[0]);
            Minutes(c, arr[1]);
            Hours(c, arr[2]);
            Month(c, arr[4]);
            if (arr.Length < 7)
            {
                Year(c, null);
            }
            else
            {
                Year(c, arr[6]);
            }
            int addtime = 1;
            while (true)
            {
                if (c.Seconds[now.Second] == 1 && c.Minutes[now.Minute] == 1 && c.Hours[now.Hour] == 1 && c.Month[now.Month - 1] == 1 && c.Year[now.Year - 2019] == 1)
                {
                    if (arr[3] != "?")
                    {
                        Days(c, arr[3], DateTime.DaysInMonth(now.Year, now.Month), now);
                        int DayOfWeek = (((int)now.DayOfWeek) + 6) % 7;
                        if (c.Days[now.Day - 1] == 1 && c.Weeks[DayOfWeek] == 1)
                        {
                            lits.Add(now);
                        }
                    }
                    else
                    {
                        Weeks(c, arr[5], DateTime.DaysInMonth(now.Year, now.Month), now);
                        int DayOfWeek = (((int)now.DayOfWeek) + 6) % 7;
                        if (c.Days[now.Day - 1] == 1 && c.Weeks[DayOfWeek] == 1)
                        {
                            lits.Add(now);
                        }
                    }
                }
                if (lits.Count >= 5)
                {
                    break;
                }
                c.Init();
                if (!arr[1].Contains('-') && !arr[1].Contains(',') && !arr[1].Contains('*') && !arr[1].Contains('/'))
                {
                    if (now.Minute == int.Parse(arr[1]))
                    {
                        addtime = 3600;
                    }
                }
                else if (arr[0] == "0" && now.Second == 0)
                {
                    addtime = 60;
                }
                now = now.AddSeconds(addtime);
            }
            return lits;
        }
        catch
        {
            return null;
        }
    }

    /// 

    /// Cron表达式转换(默认开始时间为当前)
    /// 
    /// 表达式
    /// 最近要执行的时间字符串
    public static string GetNextDateTime(string cron)
    {
        try
        {
            DateTime now = DateTime.Now;
            string[] arr = cron.Split(' ');
            if (IsOrNoOne(cron))
            {
                string date = arr[6] + "/" + arr[4] + "/" + arr[3] + " " + arr[2] + ":" + arr[1] + ":" + arr[0];
                if (DateTime.Compare(Convert.ToDateTime(date), now) >= 0)
                {
                    return date;
                }
                else
                {
                    return null;
                }
            }
            Cron c = new Cron();
            Seconds(c, arr[0]);
            Minutes(c, arr[1]);
            Hours(c, arr[2]);
            Month(c, arr[4]);
            if (arr.Length < 7)
            {
                Year(c, null);
            }
            else
            {
                Year(c, arr[6]);
            }
            int addtime = 1;
            while (true)
            {
                if (c.Seconds[now.Second] == 1 && c.Minutes[now.Minute] == 1 && c.Hours[now.Hour] == 1 && c.Month[now.Month - 1] == 1 && c.Year[now.Year - 2019] == 1)
                {
                    if (arr[3] != "?")
                    {
                        Days(c, arr[3], DateTime.DaysInMonth(now.Year, now.Month), now);
                        int DayOfWeek = (((int)now.DayOfWeek) + 6) % 7;
                        if (c.Days[now.Day - 1] == 1 && c.Weeks[DayOfWeek] == 1)
                        {
                            return now.ToString("yyyy/MM/dd HH:mm:ss");
                        }
                    }
                    else
                    {
                        Weeks(c, arr[5], DateTime.DaysInMonth(now.Year, now.Month), now);
                        int DayOfWeek = (((int)now.DayOfWeek) + 6) % 7;
                        if (c.Days[now.Day - 1] == 1 && c.Weeks[DayOfWeek] == 1)
                        {
                            return now.ToString("yyyy/MM/dd HH:mm:ss");
                        }
                    }
                }
                c.Init();
                if (!arr[1].Contains('-') && !arr[1].Contains(',') && !arr[1].Contains('*') && !arr[1].Contains('/'))
                {
                    if (now.Minute == int.Parse(arr[1]))
                    {
                        addtime = 3600;
                    }
                }
                else if (arr[0] == "0" && now.Second == 0)
                {
                    addtime = 60;
                }
                now = now.AddSeconds(addtime);
            }
        }
        catch
        {
            return null;
        }
    }

    /// 

    /// Cron表达式转换（自定义开始时间）
    /// 
    /// 表达式
    /// 开始时间
    /// 最近要执行的时间字符串
    public static string GetNextDateTime(string cron, DateTime now)
    {
        try
        {
            string[] arr = cron.Split(' ');
            if (IsOrNoOne(cron))
            {
                string date = arr[6] + "/" + arr[4] + "/" + arr[3] + " " + arr[2] + ":" + arr[1] + ":" + arr[0];
                if(DateTime.Compare(Convert.ToDateTime(date),now)>0)
                {
                    return date;
                }
                else
                {
                    return null;
                }
            }
            Cron c = new Cron();
            Seconds(c, arr[0]);
            Minutes(c, arr[1]);
            Hours(c, arr[2]);
            Month(c, arr[4]);
            if (arr.Length < 7)
            {
                Year(c, null);
            }
            else
            {
                Year(c, arr[6]);
            }
            int addtime = 1;
            while (true)
            {
                if (c.Seconds[now.Second] == 1 && c.Minutes[now.Minute] == 1 && c.Hours[now.Hour] == 1 && c.Month[now.Month - 1] == 1 && c.Year[now.Year - 2019] == 1)
                {
                    if (arr[3] != "?")
                    {
                        Days(c, arr[3], DateTime.DaysInMonth(now.Year, now.Month), now);
                        int DayOfWeek = (((int)now.DayOfWeek) + 6) % 7;
                        if (c.Days[now.Day - 1] == 1 && c.Weeks[DayOfWeek] == 1)
                        {
                            return now.ToString("yyyy/MM/dd HH:mm:ss");
                        }
                    }
                    else
                    {
                        Weeks(c, arr[5], DateTime.DaysInMonth(now.Year, now.Month), now);
                        int DayOfWeek = (((int)now.DayOfWeek) + 6) % 7;
                        if (c.Days[now.Day - 1] == 1 && c.Weeks[DayOfWeek] == 1)
                        {
                            return now.ToString("yyyy/MM/dd HH:mm:ss");
                        }
                    }
                }
                c.Init();
                if (!arr[1].Contains('-') && !arr[1].Contains(',') && !arr[1].Contains('*') && !arr[1].Contains('/'))
                {
                    if (now.Minute == int.Parse(arr[1]))
                    {
                        addtime = 3600;
                    }
                }
                else if (arr[0] == "0" && now.Second == 0)
                {
                    addtime = 60;
                }
                now = now.AddSeconds(addtime);
            }
        }
        catch
        {
            return null;
        }
    }

    /// 

    /// Cron表达式转换成中文描述
    /// 
    /// 
    /// 
    public static string TranslateToChinese(string cronExp)
    {
        if (cronExp == null || cronExp.Length < 1)
        {
            return "cron表达式为空";
        }
        string[] tmpCorns = cronExp.Split(" ");
        StringBuilder sBuffer = new StringBuilder();
        if (tmpCorns.Length == 6)
        {
            //解析月
            if (!tmpCorns[4].Equals("*"))
            {
                sBuffer.Append(tmpCorns[4]).Append("月");
            }
            else
            {
                sBuffer.Append("每月");
            }
            //解析周
            if (!tmpCorns[5].Equals("*") && !tmpCorns[5].Equals("?"))
            {
                char[] tmpArray = tmpCorns[5].ToCharArray();
                foreach (char tmp in tmpArray)
                {
                    switch (tmp)
                    {
                        case '1':
                            sBuffer.Append("星期天");
                            break;
                        case '2':
                            sBuffer.Append("星期一");
                            break;
                        case '3':
                            sBuffer.Append("星期二");
                            break;
                        case '4':
                            sBuffer.Append("星期三");
                            break;
                        case '5':
                            sBuffer.Append("星期四");
                            break;
                        case '6':
                            sBuffer.Append("星期五");
                            break;
                        case '7':
                            sBuffer.Append("星期六");
                            break;
                        case '-':
                            sBuffer.Append("至");
                            break;
                        default:
                            sBuffer.Append(tmp);
                            break;
                    }
                }
            }

            //解析日
            if (!tmpCorns[3].Equals("?"))
            {
                if (!tmpCorns[3].Equals("*"))
                {
                    sBuffer.Append(tmpCorns[3]).Append("日");
                }
                else
                {
                    sBuffer.Append("每日");
                }
            }

            //解析时
            if (!tmpCorns[2].Equals("*"))
            {
                sBuffer.Append(tmpCorns[2]).Append("时");
            }
            else
            {
                sBuffer.Append("每时");
            }

            //解析分
            if (!tmpCorns[1].Equals("*"))
            {
                sBuffer.Append(tmpCorns[1]).Append("分");
            }
            else
            {
                sBuffer.Append("每分");
            }

            //解析秒
            if (!tmpCorns[0].Equals("*"))
            {
                sBuffer.Append(tmpCorns[0]).Append("秒");
            }
            else
            {
                sBuffer.Append("每秒");
            }
        }
        return sBuffer.ToString();
    }

    #region 初始化Cron对象
    private static void Seconds(Cron c, string str)
    {
        if (str == "*")
        {
            for (int i = 0; i < 60; i++)
            {
                c.Seconds[i] = 1;
            }
        }
        else if (str.Contains('-'))
        {
            int begin = int.Parse(str.Split('-')[0]);
            int end = int.Parse(str.Split('-')[1]);
            for (int i = begin; i <= end; i++)
            {
                c.Seconds[i] = 1;
            }
        }
        else if (str.Contains('/'))
        {
            int begin = int.Parse(str.Split('/')[0]);
            int interval = int.Parse(str.Split('/')[1]);
            while (true)
            {
                c.Seconds[begin] = 1;
                if ((begin + interval) >= 60)
                    break;
                begin += interval;
            }
        }
        else if (str.Contains(','))
        {

            for (int i = 0; i < str.Split(',').Length; i++)
            {
                c.Seconds[int.Parse(str.Split(',')[i])] = 1;
            }
        }
        else
        {
            c.Seconds[int.Parse(str)] = 1;
        }
    }
    private static void Minutes(Cron c, string str)
    {
        if (str == "*")
        {
            for (int i = 0; i < 60; i++)
            {
                c.Minutes[i] = 1;
            }
        }
        else if (str.Contains('-'))
        {
            int begin = int.Parse(str.Split('-')[0]);
            int end = int.Parse(str.Split('-')[1]);
            for (int i = begin; i <= end; i++)
            {
                c.Minutes[i] = 1;
            }
        }
        else if (str.Contains('/'))
        {
            int begin = int.Parse(str.Split('/')[0]);
            int interval = int.Parse(str.Split('/')[1]);
            while (true)
            {
                c.Minutes[begin] = 1;
                if ((begin + interval) >= 60)
                    break;
                begin += interval;
            }
        }
        else if (str.Contains(','))
        {

            for (int i = 0; i < str.Split(',').Length; i++)
            {
                c.Minutes[int.Parse(str.Split(',')[i])] = 1;
            }
        }
        else
        {
            c.Minutes[int.Parse(str)] = 1;
        }
    }
    private static void Hours(Cron c, string str)
    {
        if (str == "*")
        {
            for (int i = 0; i < 24; i++)
            {
                c.Hours[i] = 1;
            }
        }
        else if (str.Contains('-'))
        {
            int begin = int.Parse(str.Split('-')[0]);
            int end = int.Parse(str.Split('-')[1]);
            for (int i = begin; i <= end; i++)
            {
                c.Hours[i] = 1;
            }
        }
        else if (str.Contains('/'))
        {
            int begin = int.Parse(str.Split('/')[0]);
            int interval = int.Parse(str.Split('/')[1]);
            while (true)
            {
                c.Hours[begin] = 1;
                if ((begin + interval) >= 24)
                    break;
                begin += interval;
            }
        }
        else if (str.Contains(','))
        {

            for (int i = 0; i < str.Split(',').Length; i++)
            {
                c.Hours[int.Parse(str.Split(',')[i])] = 1;
            }
        }
        else
        {
            c.Hours[int.Parse(str)] = 1;
        }
    }
    private static void Month(Cron c, string str)
    {
        if (str == "*")
        {
            for (int i = 0; i < 12; i++)
            {
                c.Month[i] = 1;
            }
        }
        else if (str.Contains('-'))
        {
            int begin = int.Parse(str.Split('-')[0]);
            int end = int.Parse(str.Split('-')[1]);
            for (int i = begin; i <= end; i++)
            {
                c.Month[i - 1] = 1;
            }
        }
        else if (str.Contains('/'))
        {
            int begin = int.Parse(str.Split('/')[0]);
            int interval = int.Parse(str.Split('/')[1]);
            while (true)
            {
                c.Month[begin - 1] = 1;
                if ((begin + interval) >= 12)
                    break;
                begin += interval;
            }
        }
        else if (str.Contains(','))
        {

            for (int i = 0; i < str.Split(',').Length; i++)
            {
                c.Month[int.Parse(str.Split(',')[i]) - 1] = 1;
            }
        }
        else
        {
            c.Month[int.Parse(str) - 1] = 1;
        }
    }
    private static void Year(Cron c, string str)
    {
        if (str == null || str == "*")
        {
            for (int i = 0; i < 80; i++)
            {
                c.Year[i] = 1;
            }
        }
        else if (str.Contains('-'))
        {
            int begin = int.Parse(str.Split('-')[0]);
            int end = int.Parse(str.Split('-')[1]);
            for (int i = begin - 2019; i <= end - 2019; i++)
            {
                c.Year[i] = 1;
            }
        }
        else
        {
            c.Year[int.Parse(str) - 2019] = 1;
        }
    }
    private static void Days(Cron c, string str, int len, DateTime now)
    {
        for (int i = 0; i < 7; i++)
        {
            c.Weeks[i] = 1;
        }
        if (str == "*" || str == "?")
        {
            for (int i = 0; i < len; i++)
            {
                c.Days[i] = 1;
            }
        }
        else if (str.Contains('-'))
        {
            int begin = int.Parse(str.Split('-')[0]);
            int end = int.Parse(str.Split('-')[1]);
            for (int i = begin; i <= end; i++)
            {
                c.Days[i - 1] = 1;
            }
        }
        else if (str.Contains('/'))
        {
            int begin = int.Parse(str.Split('/')[0]);
            int interval = int.Parse(str.Split('/')[1]);
            while (true)
            {
                c.Days[begin - 1] = 1;
                if ((begin + interval) >= len)
                    break;
                begin += interval;
            }
        }
        else if (str.Contains(','))
        {
            for (int i = 0; i < str.Split(',').Length; i++)
            {
                c.Days[int.Parse(str.Split(',')[i]) - 1] = 1;
            }
        }
        else if (str.Contains('L'))
        {
            int i = str.Replace("L", "") == "" ? 0 : int.Parse(str.Replace("L", ""));
            c.Days[len - 1 - i] = 1;
        }
        else if (str.Contains('W'))
        {
            c.Days[len - 1] = 1;
        }
        else
        {
            c.Days[int.Parse(str) - 1] = 1;
        }
    }
    private static void Weeks(Cron c, string str, int len, DateTime now)
    {
        if (str == "*" || str == "?")
        {
            for (int i = 0; i < 7; i++)
            {
                c.Weeks[i] = 1;
            }
        }
        else if (str.Contains('-'))
        {
            int begin = int.Parse(str.Split('-')[0]);
            int end = int.Parse(str.Split('-')[1]);
            for (int i = begin; i <= end; i++)
            {
                c.Weeks[i - 1] = 1;
            }
        }
        else if (str.Contains(','))
        {
            for (int i = 0; i < str.Split(',').Length; i++)
            {
                c.Weeks[int.Parse(str.Split(',')[i]) - 1] = 1;
            }
        }
        else if (str.Contains('L'))
        {
            int i = str.Replace("L", "") == "" ? 0 : int.Parse(str.Replace("L", ""));
            if (i == 0)
            {
                c.Weeks[6] = 1;
            }
            else
            {
                c.Weeks[i - 1] = 1;
                c.Days[GetLastWeek(i, now) - 1] = 1;
                return;
            }
        }
        else if (str.Contains('#'))
        {
            int i = int.Parse(str.Split('#')[0]);
            int j = int.Parse(str.Split('#')[1]);
            c.Weeks[i - 1] = 1;
            c.Days[GetWeek(i - 1, j, now)] = 1;
            return;
        }
        else
        {
            c.Weeks[int.Parse(str) - 1] = 1;
        }
        //week中初始化day，则说明day没要求
        for (int i = 0; i < len; i++)
        {
            c.Days[i] = 1;
        }
    }
    #endregion

    #region 方法

    public static bool IsOrNoOne(string cron)
    {
        if (cron.Contains('-') || cron.Contains(',') || cron.Contains('/') || cron.Contains('*'))
        {
            return false;
        }
        else
        {
            return true;
        }
    }

    /// 

    /// 获取最后一个星期几的day
    /// 
    /// 星期几
    /// 
    /// 
    private static int GetLastWeek(int i, DateTime now)
    {
        DateTime d = now.AddDays(1 - now.Day).Date.AddMonths(1).AddSeconds(-1);
        int DayOfWeek = ((((int)d.DayOfWeek) + 6) % 7) + 1;
        int a = DayOfWeek >= i ? DayOfWeek - i : 7 + DayOfWeek - i;
        return DateTime.DaysInMonth(now.Year, now.Month) - a;
    }
    /// 

    /// 获取当月第几个星期几的day
    /// 
    /// 星期几
    /// 第几周
    /// 
    /// 
    public static int GetWeek(int i, int j, DateTime now)
    {
        int day = 0;
        DateTime d = new DateTime(now.Year, now.Month, 1);
        int DayOfWeek = ((((int)d.DayOfWeek) + 6) % 7) + 1;
        if (i >= DayOfWeek)
        {
            day = (7 - DayOfWeek + 1) + 7 * (j - 2) + i;
        }
        else
        {
            day = (7 - DayOfWeek + 1) + 7 * (j - 1) + i;
        }
        return day;
    }
    #endregion

}

调用方法示例

string cron="0 15 10 * * ?";
CronHelp.GetNextDateTime(cron, DateTime.Now);
CronHelp.CronToDateTime(cron, DateTime.Now);
CronHelp.CronToDateTime(cron);