增加字符串默认值扩展，增加ArrayStringJson转换特性。

Falcon.SugarApi.Test/Falcon.SugarApi.Test.csproj

@@ -3,7 +3,7 @@
 	<PropertyGroup>
 		<TargetFrameworks>net5</TargetFrameworks>
 		<Nullable>enable</Nullable>
-
+		<DocumentationFile>bin\$(Configuration)\$(TargetFramework)\$(AssemblyName).xml</DocumentationFile>
 		<IsPackable>false</IsPackable>
 	</PropertyGroup>
 

Falcon.SugarApi.Test/StringExtendTest.cs

@@ -29,6 +29,37 @@ namespace Falcon.SugarApi.Test
             strArr = str.SplitStr();
             Assert.IsNotNull(strArr);
             Assert.AreEqual(0, strArr.Length);
+
+            //指定分隔符
+            str = $"a,b.c;d，e。f；g";
+
+            strArr = str.SplitStr(',');
+            Assert.AreEqual(2, strArr.Length, "分割后长度应该为7");
+            Assert.AreEqual("a", strArr[0]);
+            Assert.AreEqual("b.c;d，e。f；g", strArr[1]);
+
+            strArr = str.SplitStr(',', '.');
+            Assert.AreEqual(3, strArr.Length, "分割后长度应该为7");
+            Assert.AreEqual("a", strArr[0]);
+            Assert.AreEqual("b", strArr[1]);
+            Assert.AreEqual("c;d，e。f；g", strArr[2]);
+        }
+
+        /// <summary>
+        /// 测试ToDefault
+        /// </summary>
+        [TestMethod]
+        public void TestToDefault() {
+            var str = "";
+            var r = "";
+            r = str.ToDefault("abc");
+            Assert.AreEqual("abc", r);
+            str = null;
+            r = str.ToDefault("abc");
+            Assert.AreEqual("abc", r);
+            str = "123";
+            r = str.ToDefault("abc");
+            Assert.AreEqual("123", r);
         }
     }
 }

Falcon.SugarApi/DatabaseDefinitions/SugarConnectionConfig.cs

@@ -1,8 +1,8 @@
 using SqlSugar;
 using System;
 using System.ComponentModel.DataAnnotations;
-using System.Reflection;
 using System.Linq;
+using System.Reflection;
 
 namespace Falcon.SugarApi.DatabaseDefinitions
 {
@@ -20,6 +20,7 @@ namespace Falcon.SugarApi.DatabaseDefinitions
         /// </summary>
         public SugarConnectionConfig() {
             this.ConfigureExternalServices ??= new ConfigureExternalServices { };
+            //设置Nullable
             this.ConfigureExternalServices.EntityService += (p, c) => {
                 var pt = p.PropertyType;
                 if (pt.GetCustomAttribute<RequiredAttribute>() != null) {

Falcon.SugarApi/DatabaseDefinitions/SugarDbContext.cs

@@ -144,7 +144,7 @@ namespace Falcon.SugarApi.DatabaseDefinitions
 
         #endregion
 
-        #region 初始化
+        #region 表初始化
         /// <summary>
         /// 已经初始化的类型列表
         /// </summary>

Falcon.SugarApi/JsonSerialize/ArrayJsonConverter.cs

@@ -0,0 +1,43 @@
+using System;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace Falcon.SugarApi.JsonSerialize
+{
+    /// <summary>
+    /// 序列化字符串属性到数组
+    /// </summary>
+    public class ArrayJsonConverter : JsonConverter<string>
+    {
+        /// <summary>
+        /// 字符串分隔符数组
+        /// </summary>
+        public char[]? SplitChars { get; set; } = null;
+
+        /// <inheritdoc/>
+        public override string? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) {
+            var str = reader.GetString().ToDefault("")!;
+            var array = JsonSerializer.Deserialize<string[]>(str) ?? new string[] { };
+            return string.Join(',', array);
+        }
+        /// <inheritdoc/>
+        public override void Write(Utf8JsonWriter writer, string value, JsonSerializerOptions options) {
+            var array = this.SplitChars == null ? value.SplitStr() : value.SplitStr(this.SplitChars);
+            var arrStr = JsonSerializer.Serialize(array);
+            writer.WriteStringValue(arrStr);
+        }
+    }
+
+    /// <summary>
+    /// 标记属性，表示这个一个数组，序列化时将会被序列化为一个以特殊字符分割的字符串数组
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = false)]
+    public class ArrayStringJsonConverterAttribute : JsonConverterAttribute
+    {
+        /// <summary>
+        /// 标记属性，表示这个一个数组，序列化时将会被序列化为一个以特殊字符分割的字符串数组
+        /// </summary>
+        public ArrayStringJsonConverterAttribute() : base(typeof(ArrayJsonConverter)) { }
+    }
+
+}

README.md

@@ -29,6 +29,7 @@
 
 ### JSON序列化扩展模块  [进入](/Falcon/Falcon.SugarApi/src/branch/master/Falcon.SugarApi/JsonSerialize)   
 >  `IServiceCollection.AddJsonSerializeFactory`方法注册Json序列化工厂`JsonSerializeFactory`，可以通过该工厂实例化一个Json序列化器。   
+>  `ArrayStringJsonConverterAttribute`特性标记字符串是个数组字符串，当进行序列化时候会被序列化为数组。  
 
 ### 字符串扩展方法    
 >  `IsNullOrEmpty()`和`IsNotNullOrEmpty()`方法返回字符串是否为空。