diff --git a/Falcon.SugarApi.Test/CronExpressionTests.cs b/Falcon.SugarApi.Test/CronExpressionTests.cs
index 068ff5f..ddcdac2 100644
--- a/Falcon.SugarApi.Test/CronExpressionTests.cs
+++ b/Falcon.SugarApi.Test/CronExpressionTests.cs
@@ -1,4 +1,5 @@
-using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Falcon.SugarApi.TimedBackgroundTask;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
 using System;
 
 namespace Falcon.SugarApi.Test
@@ -12,10 +13,7 @@ namespace Falcon.SugarApi.Test
 
             var cron = new CronExpression("0 30 3 * * 1-5"); // 工作日凌晨3:30:00
             var nextTime = cron.GetNextOccurrence(now20250213102512);
-            if(nextTime == null) {
-                Assert.Fail("nextTime is null!");
-                return;
-            }
+
             Assert.IsTrue(DateToString(nextTime) == "20250214033000");
             cron = new CronExpression("");//下一秒触发
             nextTime = cron.GetNextOccurrence(now20250213102512);
diff --git a/Falcon.SugarApi/TimedBackgroundTask/CronExpression.cs b/Falcon.SugarApi/TimedBackgroundTask/CronExpression.cs
index 85033a9..4fb90ff 100644
--- a/Falcon.SugarApi/TimedBackgroundTask/CronExpression.cs
+++ b/Falcon.SugarApi/TimedBackgroundTask/CronExpression.cs
@@ -1,242 +1,245 @@
-using Falcon.SugarApi;
-using Falcon.SugarApi.TimedBackgroundTask;
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 
-/// <summary>
-/// Cron表达式
-/// </summary>
-public class CronExpression
+namespace Falcon.SugarApi.TimedBackgroundTask
 {
-    /// <summary>
-    /// 可选的秒范围枚举
-    /// </summary>
-    private List<int> Seconds { get; }
-    /// <summary>
-    /// 可选的分范围枚举
-    /// </summary>
-    private List<int> Minutes { get; }
-    /// <summary>
-    /// 可选的时范围枚举
-    /// </summary>
-    private List<int> Hours { get; }
-    /// <summary>
-    /// 可选的天范围枚举
-    /// </summary>
-    private List<int> DaysOfMonth { get; }
-    /// <summary>
-    /// 可选的月范围枚举
-    /// </summary>
-    private List<int> Months { get; }
-    /// <summary>
-    /// 可选的星期范围枚举
-    /// </summary>
-    private List<int> DaysOfWeek { get; }
-    /// <summary>
-    /// 可选的年范围枚举
-    /// </summary>
-    private List<int> Years { get; set; }
 
     /// <summary>
-    /// 通过提供cron表达式构造对象
-    /// <para>表达式以空格分隔，按顺序每一段分别为“秒,分,时,日,月,星期,年”</para>
-    /// <para>取值范围：秒分时取值范围0-59，日取值范围1-31，月取值范围1-12，星期取值范围0-6，年取值范围两年内</para>
-    /// <para>取值*表示可以匹配任意值，比如*表示每一秒，* *表示所有分秒。</para>
-    /// <para>取值-表示取值范围，比如1-5 3匹配3分1秒到3分5秒所有时间。</para>
-    /// <para>取值/表示周期取值，比如0/10表示0秒开始每10秒匹配一次。</para>
-    /// <para>取值可以用，分割，表示取值枚举，比如0 10,20,30 5 表示匹配每天早上5点10分、5点20分和5点30分。</para>
-    /// <para>表达式右侧的*可以省略。比如0 15 4表示每天上午4点15分，和0 15 4 * * * *相同</para>
-    /// <para>星期取值范围0-6，0表示星期天，1表示星期一，以此类推。</para>
-    /// <para>日取值范围1-31，不用考虑大月小月和二月的特殊情况，方法会自动处理这些特殊日期</para>
-    /// <para>关于日期和星期匹配问题。一般的cron标准中日期和星期只要满足一个即可匹配，但本方法不同，我认为既然其他所有部分(比如分和秒)都是必须同时满足，那么日期和星期也是必须同时满足。</para>
-    /// <para>目前方法不支持*-/,分隔符的混合使用，等待后续改进</para>
+    /// Cron表达式
     /// </summary>
-    /// <param name="cronExpression">cron表达式</param>
-    /// <exception cref="ArgumentException"></exception>
-    public CronExpression(string cronExpression) {
-        var fields = cronExpression.Split(new[] { ' ' },StringSplitOptions.RemoveEmptyEntries);
+    public class CronExpression
+    {
+        /// <summary>
+        /// 可选的秒范围枚举
+        /// </summary>
+        private List<int> Seconds { get; }
+        /// <summary>
+        /// 可选的分范围枚举
+        /// </summary>
+        private List<int> Minutes { get; }
+        /// <summary>
+        /// 可选的时范围枚举
+        /// </summary>
+        private List<int> Hours { get; }
+        /// <summary>
+        /// 可选的天范围枚举
+        /// </summary>
+        private List<int> DaysOfMonth { get; }
+        /// <summary>
+        /// 可选的月范围枚举
+        /// </summary>
+        private List<int> Months { get; }
+        /// <summary>
+        /// 可选的星期范围枚举
+        /// </summary>
+        private List<int> DaysOfWeek { get; }
+        /// <summary>
+        /// 可选的年范围枚举
+        /// </summary>
+        private List<int> Years { get; set; }
 
-        Seconds = fields.Length > 0 ? GetRange(fields[0],0,59) : Enumerable.Range(0,60).ToList();
-        Minutes = fields.Length > 1 ? GetRange(fields[1],0,59) : Enumerable.Range(0,60).ToList();
-        Hours = fields.Length > 2 ? GetRange(fields[2],0,23) : Enumerable.Range(0,24).ToList();
-        DaysOfMonth = fields.Length > 3 ? GetRange(fields[3],1,31) : Enumerable.Range(1,31).ToList();
-        Months = fields.Length > 4 ? GetRange(fields[4],1,12) : Enumerable.Range(1,12).ToList();
-        DaysOfWeek = fields.Length > 5 ? GetRange(fields[5],0,6) : Enumerable.Range(0,7).ToList();
-        var nowYear = DateTime.Now.Year;
-        Years = fields.Length > 6 ? GetRange(fields[6],nowYear,nowYear + 2) : Enumerable.Range(nowYear,2).ToList();
-    }
+        /// <summary>
+        /// 通过提供cron表达式构造对象
+        /// <para>表达式以空格分隔，按顺序每一段分别为“秒,分,时,日,月,星期,年”</para>
+        /// <para>取值范围：秒分时取值范围0-59，日取值范围1-31，月取值范围1-12，星期取值范围0-6，年取值范围两年内</para>
+        /// <para>取值*表示可以匹配任意值，比如*表示每一秒，* *表示所有分秒。</para>
+        /// <para>取值-表示取值范围，比如1-5 3匹配3分1秒到3分5秒所有时间。</para>
+        /// <para>取值/表示周期取值，比如0/10表示0秒开始每10秒匹配一次。</para>
+        /// <para>取值可以用，分割，表示取值枚举，比如0 10,20,30 5 表示匹配每天早上5点10分、5点20分和5点30分。</para>
+        /// <para>表达式右侧的*可以省略。比如0 15 4表示每天上午4点15分，和0 15 4 * * * *相同</para>
+        /// <para>星期取值范围0-6，0表示星期天，1表示星期一，以此类推。</para>
+        /// <para>日取值范围1-31，不用考虑大月小月和二月的特殊情况，方法会自动处理这些特殊日期</para>
+        /// <para>关于日期和星期匹配问题。一般的cron标准中日期和星期只要满足一个即可匹配，但本方法不同，我认为既然其他所有部分(比如分和秒)都是必须同时满足，那么日期和星期也是必须同时满足。</para>
+        /// <para>目前方法不支持*-/,分隔符的混合使用，等待后续改进</para>
+        /// </summary>
+        /// <param name="cronExpression">cron表达式</param>
+        /// <exception cref="ArgumentException"></exception>
+        public CronExpression(string cronExpression) {
+            var fields = cronExpression.Split(new[] { ' ' },StringSplitOptions.RemoveEmptyEntries);
 
-    /// <summary>
-    /// 通过提供的时间获取下一次时间
-    /// </summary>
-    /// <param name="afterTime">上一次的时间</param>
-    /// <returns>下一次到达时间</returns>
-    public DateTime GetNextOccurrence(DateTime afterTime) {
-        var ct = new CronResult(afterTime.AddSeconds(1));
-        while(!ct.IsAllAdjust) {
-            if(!ct.IsYearAdjust) {
-                AdjustYear(ct);
-            }
-            if(!ct.IsMonthAdjust) {
-                AdjustMonth(ct);
+            Seconds = fields.Length > 0 ? GetRange(fields[0],0,59) : Enumerable.Range(0,60).ToList();
+            Minutes = fields.Length > 1 ? GetRange(fields[1],0,59) : Enumerable.Range(0,60).ToList();
+            Hours = fields.Length > 2 ? GetRange(fields[2],0,23) : Enumerable.Range(0,24).ToList();
+            DaysOfMonth = fields.Length > 3 ? GetRange(fields[3],1,31) : Enumerable.Range(1,31).ToList();
+            Months = fields.Length > 4 ? GetRange(fields[4],1,12) : Enumerable.Range(1,12).ToList();
+            DaysOfWeek = fields.Length > 5 ? GetRange(fields[5],0,6) : Enumerable.Range(0,7).ToList();
+            var nowYear = DateTime.Now.Year;
+            Years = fields.Length > 6 ? GetRange(fields[6],nowYear,nowYear + 2) : Enumerable.Range(nowYear,2).ToList();
+        }
+
+        /// <summary>
+        /// 通过提供的时间获取下一次时间
+        /// </summary>
+        /// <param name="afterTime">上一次的时间</param>
+        /// <returns>下一次到达时间</returns>
+        public DateTime GetNextOccurrence(DateTime afterTime) {
+            var ct = new CronResult(afterTime.AddSeconds(1));
+            while(!ct.IsAllAdjust) {
                 if(!ct.IsYearAdjust) {
-                    continue;
+                    AdjustYear(ct);
+                }
+                if(!ct.IsMonthAdjust) {
+                    AdjustMonth(ct);
+                    if(!ct.IsYearAdjust) {
+                        continue;
+                    }
+                }
+                if(!ct.IsDayAdjust) {
+                    AdjustDay(ct);
+                    if(!ct.IsYearAdjust || !ct.IsMonthAdjust || !ct.IsDayAdjust) {
+                        continue;
+                    }
+                }
+                if(!ct.IsHourAdjust) {
+                    AdjustHour(ct);
+                    if(!ct.IsYearAdjust || !ct.IsMonthAdjust || !ct.IsDayAdjust) {
+                        continue;
+                    }
+                }
+                if(!ct.IsMinuteAdjust) {
+                    AdjustMinute(ct);
+                    if(!ct.IsYearAdjust || !ct.IsMonthAdjust || !ct.IsDayAdjust || !ct.IsHourAdjust) {
+                        continue;
+                    }
+                }
+                if(!ct.IsSecondAdjust) {
+                    AdjustSecond(ct);
                 }
             }
-            if(!ct.IsDayAdjust) {
-                AdjustDay(ct);
-                if(!ct.IsYearAdjust || !ct.IsMonthAdjust || !ct.IsDayAdjust) {
-                    continue;
+            return ct.AdjustTime;
+        }
+
+        private void AdjustYear(CronResult date) {
+            var next = Years.Where(a => a >= date.AdjustTime.Year);
+            if(next.Any()) {
+                date.SetAdjustTime(date.AdjustTime.AddYears(next.First() - date.AdjustTime.Year),TimePartEnum.Year);
+                date.IsYearAdjust = true;
+            }
+            else {
+                date.IsNullVal = true;
+                date.IsYearAdjust = true;
+                date.IsMonthAdjust = true;
+                date.IsDayAdjust = true;
+                date.IsHourAdjust = true;
+                date.IsMinuteAdjust = true;
+                date.IsSecondAdjust = true;
+                date.AdjustTime = DateTime.MaxValue;
+            }
+        }
+
+        private void AdjustMonth(CronResult date) {
+            var next = Months.Where(m => m >= date.AdjustTime.Month);
+            if(next.Any()) {
+                date.SetAdjustTime(date.AdjustTime.AddMonths(next.First() - date.AdjustTime.Month),TimePartEnum.YearMonth);
+                date.IsMonthAdjust = true;
+            }
+            else {
+                date.SetAdjustTime(date.AdjustTime.AddYears(1),TimePartEnum.YearMonth);
+            }
+        }
+
+        private void AdjustDay(CronResult date) {
+            var dt = date.AdjustTime;
+            int year = dt.Year;
+            int month = dt.Month;
+            int day = dt.Day;
+            int maxDayInMonth = DateTime.DaysInMonth(year,month);
+            var next = DaysOfMonth.Where(a => a >= day && a <= maxDayInMonth && DaysOfWeek.Contains((int)dt.DayOfWeek));
+            if(next.Any()) {
+                date.SetAdjustTime(dt.AddDays(next.First() - day),TimePartEnum.YearDay);
+                date.IsDayAdjust = true;
+                return;
+            }
+            if(!DaysOfWeek.Contains((int)dt.DayOfWeek)) {
+                date.SetAdjustTime(dt.AddDays(1),TimePartEnum.YearDay);
+                return;
+            }
+            date.SetAdjustTime(dt.AddMonths(1),TimePartEnum.YearMonth);
+        }
+
+        private void AdjustHour(CronResult date) {
+            var next = Hours.Where(m => m >= date.AdjustTime.Hour);
+            if(next.Any()) {
+                date.SetAdjustTime(date.AdjustTime.AddHours(next.First() - date.AdjustTime.Hour),TimePartEnum.YearHour);
+                date.IsHourAdjust = true;
+                return;
+            }
+            date.SetAdjustTime(date.AdjustTime.AddDays(1),TimePartEnum.YearHour);
+        }
+
+        private void AdjustMinute(CronResult date) {
+            var next = Minutes.Where(m => m >= date.AdjustTime.Minute);
+            if(next.Any()) {
+                date.SetAdjustTime(date.AdjustTime.AddMinutes(next.First() - date.AdjustTime.Minute),TimePartEnum.YearMinute);
+                date.IsMinuteAdjust = true;
+                return;
+            }
+            date.SetAdjustTime(date.AdjustTime.AddHours(1),TimePartEnum.YearMinute);
+        }
+
+        private void AdjustSecond(CronResult date) {
+            var next = Seconds.Where(m => m >= date.AdjustTime.Second);
+            if(next.Any()) {
+                date.SetAdjustTime(date.AdjustTime.AddSeconds(next.First() - date.AdjustTime.Second),TimePartEnum.YearSecond);
+                date.IsSecondAdjust = true;
+                return;
+            }
+            date.SetAdjustTime(date.AdjustTime.AddMinutes(1),TimePartEnum.YearSecond);
+        }
+
+        private static List<int> GetRange(string exp,int min,int max) {
+            var charList = "0123456789*-/,".ToArray();
+            var expChars = exp.ToCharArray().Distinct();
+            var outRangeChars = expChars.Where(a => a.NotIn(charList)).ToArray();
+            if(outRangeChars.Any()) {
+                throw new ArgumentOutOfRangeException(nameof(exp),$"非法字符{new string(outRangeChars)} 在表达式 {exp} 中");
+            }
+            //if(exp.ToCharArray().Any(a => a.NotIn(charList))) {
+            //    throw new ArgumentOutOfRangeException(nameof(exp));
+            //}
+            var list = new List<int>();
+            if(exp == "*") {
+                return Enumerable.Range(min,max - min + 1).ToList();
+            }
+            if(int.TryParse(exp,out int iexp) && iexp.Between(min,max)) {
+                list.Add(iexp);
+                return list;
+            }
+            if(exp.Contains('-')) {
+                var g = exp.Split('-',StringSplitOptions.RemoveEmptyEntries);
+                var i = int.Parse(g[0]);
+                var x = int.Parse(g[1]);
+                i = Math.Max(i,min);
+                x = Math.Min(x,max);
+                while(i <= x) {
+                    list.Add(i++);
                 }
+                return list;
             }
-            if(!ct.IsHourAdjust) {
-                AdjustHour(ct);
-                if(!ct.IsYearAdjust || !ct.IsMonthAdjust || !ct.IsDayAdjust) {
-                    continue;
+            if(exp.Contains('/')) {
+                var g = exp.Split('/',StringSplitOptions.RemoveEmptyEntries);
+                var f = Math.Max(min,int.Parse(g[0]));
+                var s = int.Parse(g[1]);
+                while(f <= max) {
+                    list.Add(f);
+                    f += s;
                 }
+                return list;
             }
-            if(!ct.IsMinuteAdjust) {
-                AdjustMinute(ct);
-                if(!ct.IsYearAdjust || !ct.IsMonthAdjust || !ct.IsDayAdjust || !ct.IsHourAdjust) {
-                    continue;
+            if(exp.Contains(',')) {
+                foreach(var ie in exp.Split(',')) {
+                    if(int.TryParse(ie,out int iei) && iei.Between(min,max)) {
+                        list.Add(iei);
+                    }
+                    else {
+                        throw new ArgumentException("给定的exp表达式错误，逗号分割的每一项都必须是数字",nameof(exp));
+                    }
                 }
+                return list;
             }
-            if(!ct.IsSecondAdjust) {
-                AdjustSecond(ct);
-            }
-        }
-        return ct.AdjustTime;
-    }
-
-    private void AdjustYear(CronResult date) {
-        var next = Years.Where(a => a >= date.AdjustTime.Year);
-        if(next.Any()) {
-            date.SetAdjustTime(date.AdjustTime.AddYears(next.First() - date.AdjustTime.Year),TimePartEnum.Year);
-            date.IsYearAdjust = true;
-        }
-        else {
-            date.IsNullVal = true;
-            date.IsYearAdjust = true;
-            date.IsMonthAdjust = true;
-            date.IsDayAdjust = true;
-            date.IsHourAdjust = true;
-            date.IsMinuteAdjust = true;
-            date.IsSecondAdjust = true;
-            date.AdjustTime = DateTime.MaxValue;
+            throw new ArgumentException("提供的cron表达式错误",nameof(exp));
         }
     }
 
-    private void AdjustMonth(CronResult date) {
-        var next = Months.Where(m => m >= date.AdjustTime.Month);
-        if(next.Any()) {
-            date.SetAdjustTime(date.AdjustTime.AddMonths(next.First() - date.AdjustTime.Month),TimePartEnum.YearMonth);
-            date.IsMonthAdjust = true;
-        }
-        else {
-            date.SetAdjustTime(date.AdjustTime.AddYears(1),TimePartEnum.YearMonth);
-        }
-    }
-
-    private void AdjustDay(CronResult date) {
-        var dt = date.AdjustTime;
-        int year = dt.Year;
-        int month = dt.Month;
-        int day = dt.Day;
-        int maxDayInMonth = DateTime.DaysInMonth(year,month);
-        var next = DaysOfMonth.Where(a => a >= day && a <= maxDayInMonth && DaysOfWeek.Contains((int)dt.DayOfWeek));
-        if(next.Any()) {
-            date.SetAdjustTime(dt.AddDays(next.First() - day),TimePartEnum.YearDay);
-            date.IsDayAdjust = true;
-            return;
-        }
-        if(!DaysOfWeek.Contains((int)dt.DayOfWeek)) {
-            date.SetAdjustTime(dt.AddDays(1),TimePartEnum.YearDay);
-            return;
-        }
-        date.SetAdjustTime(dt.AddMonths(1),TimePartEnum.YearMonth);
-    }
-
-    private void AdjustHour(CronResult date) {
-        var next = Hours.Where(m => m >= date.AdjustTime.Hour);
-        if(next.Any()) {
-            date.SetAdjustTime(date.AdjustTime.AddHours(next.First() - date.AdjustTime.Hour),TimePartEnum.YearHour);
-            date.IsHourAdjust = true;
-            return;
-        }
-        date.SetAdjustTime(date.AdjustTime.AddDays(1),TimePartEnum.YearHour);
-    }
-
-    private void AdjustMinute(CronResult date) {
-        var next = Minutes.Where(m => m >= date.AdjustTime.Minute);
-        if(next.Any()) {
-            date.SetAdjustTime(date.AdjustTime.AddMinutes(next.First() - date.AdjustTime.Minute),TimePartEnum.YearMinute);
-            date.IsMinuteAdjust = true;
-            return;
-        }
-        date.SetAdjustTime(date.AdjustTime.AddHours(1),TimePartEnum.YearMinute);
-    }
-
-    private void AdjustSecond(CronResult date) {
-        var next = Seconds.Where(m => m >= date.AdjustTime.Second);
-        if(next.Any()) {
-            date.SetAdjustTime(date.AdjustTime.AddSeconds(next.First() - date.AdjustTime.Second),TimePartEnum.YearSecond);
-            date.IsSecondAdjust = true;
-            return;
-        }
-        date.SetAdjustTime(date.AdjustTime.AddMinutes(1),TimePartEnum.YearSecond);
-    }
-
-    private static List<int> GetRange(string exp,int min,int max) {
-        var charList = "0123456789*-/,".ToArray();
-        var expChars = exp.ToCharArray().Distinct();
-        var outRangeChars = expChars.Where(a => a.NotIn(charList)).ToArray();
-        if(outRangeChars.Any()) {
-            throw new ArgumentOutOfRangeException(nameof(exp),$"非法字符{new string(outRangeChars)} 在表达式 {exp} 中");
-        }
-        //if(exp.ToCharArray().Any(a => a.NotIn(charList))) {
-        //    throw new ArgumentOutOfRangeException(nameof(exp));
-        //}
-        var list = new List<int>();
-        if(exp == "*") {
-            return Enumerable.Range(min,max - min + 1).ToList();
-        }
-        if(int.TryParse(exp,out int iexp) && iexp.Between(min,max)) {
-            list.Add(iexp);
-            return list;
-        }
-        if(exp.Contains('-')) {
-            var g = exp.Split('-',StringSplitOptions.RemoveEmptyEntries);
-            var i = int.Parse(g[0]);
-            var x = int.Parse(g[1]);
-            i = Math.Max(i,min);
-            x = Math.Min(x,max);
-            while(i <= x) {
-                list.Add(i++);
-            }
-            return list;
-        }
-        if(exp.Contains('/')) {
-            var g = exp.Split('/',StringSplitOptions.RemoveEmptyEntries);
-            var f = Math.Max(min,int.Parse(g[0]));
-            var s = int.Parse(g[1]);
-            while(f <= max) {
-                list.Add(f);
-                f += s;
-            }
-            return list;
-        }
-        if(exp.Contains(',')) {
-            foreach(var ie in exp.Split(',')) {
-                if(int.TryParse(ie,out int iei) && iei.Between(min,max)) {
-                    list.Add(iei);
-                }
-                else {
-                    throw new ArgumentException("给定的exp表达式错误，逗号分割的每一项都必须是数字",nameof(exp));
-                }
-            }
-            return list;
-        }
-        throw new ArgumentException("提供的cron表达式错误",nameof(exp));
-    }
 }
\ No newline at end of file