diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/Newtonsoft.Json/Boolean/YesOrNoNullableBooleanConverter.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/Newtonsoft.Json/Boolean/YesOrNoNullableBooleanConverter.cs
index fe6c8f14..09e863a4 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/Newtonsoft.Json/Boolean/YesOrNoNullableBooleanConverter.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/Newtonsoft.Json/Boolean/YesOrNoNullableBooleanConverter.cs
@@ -30,7 +30,7 @@ namespace Newtonsoft.Json.Converters
             else if (reader.TokenType == JsonToken.String)
             {
                 string? value = serializer.Deserialize<string>(reader);
-                if (value == null)
+                if (string.IsNullOrEmpty(value))
                     return existingValue;
 
                 if (CHAR_YES.Equals(value))
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/Newtonsoft.Json/DateTimeOffset/PureDigitalTextNullableDateTimeOffsetConverter.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/Newtonsoft.Json/DateTimeOffset/PureDigitalTextNullableDateTimeOffsetConverter.cs
index 0ec15768..1a011159 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/Newtonsoft.Json/DateTimeOffset/PureDigitalTextNullableDateTimeOffsetConverter.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/Newtonsoft.Json/DateTimeOffset/PureDigitalTextNullableDateTimeOffsetConverter.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Globalization;
 
 namespace Newtonsoft.Json.Converters
@@ -26,7 +26,7 @@ namespace Newtonsoft.Json.Converters
             else if (reader.TokenType == JsonToken.String)
             {
                 string? value = serializer.Deserialize<string>(reader);
-                if (value == null)
+                if (string.IsNullOrEmpty(value))
                     return existingValue;
 
                 if (DateTimeOffset.TryParseExact(value, DATETIME_FORMAT, DateTimeFormatInfo.InvariantInfo, DateTimeStyles.None, out DateTimeOffset result))
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/System.Text.Json/Boolean/YesOrNoNullableBooleanConverter.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/System.Text.Json/Boolean/YesOrNoNullableBooleanConverter.cs
index 737afca6..dc84f0aa 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/System.Text.Json/Boolean/YesOrNoNullableBooleanConverter.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/System.Text.Json/Boolean/YesOrNoNullableBooleanConverter.cs
@@ -24,7 +24,7 @@ namespace System.Text.Json.Converters
             else if (reader.TokenType == JsonTokenType.String)
             {
                 string? value = reader.GetString();
-                if (value == null)
+                if (string.IsNullOrEmpty(value))
                     return null;
 
                 if (CHAR_YES.Equals(value))
diff --git a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/System.Text.Json/DateTimeOffset/PureDigitalTextNullableDateTimeOffsetConverter.cs b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/System.Text.Json/DateTimeOffset/PureDigitalTextNullableDateTimeOffsetConverter.cs
index 1e1572e3..b6148563 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/System.Text.Json/DateTimeOffset/PureDigitalTextNullableDateTimeOffsetConverter.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.TenpayV2/Converters/Internal/System.Text.Json/DateTimeOffset/PureDigitalTextNullableDateTimeOffsetConverter.cs
@@ -1,4 +1,4 @@
-using System.Globalization;
+using System.Globalization;
 using System.Text.Json.Serialization;
 
 namespace System.Text.Json.Converters
@@ -16,7 +16,7 @@ namespace System.Text.Json.Converters
             else if (reader.TokenType == JsonTokenType.String)
             {
                 string? value = reader.GetString();
-                if (value == null)
+                if (string.IsNullOrEmpty(value))
                     return null;
 
                 if (DateTimeOffset.TryParseExact(value, DATETIME_FORMAT, DateTimeFormatInfo.InvariantInfo, DateTimeStyles.None, out DateTimeOffset result))