fix: 完善JsonNodeSerializer可空类型

src/EasilyNET.MongoSerializer.AspNetCore/JsonNodeSerializer.cs

@@ -1,26 +1,28 @@
-using MongoDB.Bson.Serialization.Serializers;
+using System.Text.Json.Nodes;
 using MongoDB.Bson.Serialization;
-using System.Text.Json.Nodes;
+using MongoDB.Bson.Serialization.Serializers;
+
+// ReSharper disable UnusedType.Global
 
 namespace EasilyNET.MongoSerializer.AspNetCore;
 
 /// <summary>
 /// JsonNode Support
 /// </summary>
-public class JsonNodeSerializer : SerializerBase<JsonNode>
+public sealed class JsonNodeSerializer : SerializerBase<JsonNode>
 {
-    const string EmptyObject = "{}";
+    private const string EmptyObject = "{}";
 
     /// <summary>
     /// if null write {}
     /// </summary>
     /// <param name="context"></param>
     /// <param name="args"></param>
     /// <param name="value"></param>
-    public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, JsonNode value)
+    public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, JsonNode? value)
     {
         var json = value?.ToString() ?? EmptyObject;
-        context?.Writer?.WriteString(json);
+        context.Writer.WriteString(json);
     }
 
     /// <summary>
@@ -31,7 +33,8 @@ public override void Serialize(BsonSerializationContext context, BsonSerializati
     /// <returns></returns>
     public override JsonNode Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
     {
-        string json = context?.Reader?.ReadString() ?? EmptyObject;
+        var value = context.Reader.ReadString();
+        var json = string.IsNullOrWhiteSpace(value) ? EmptyObject : value;
         return JsonNode.Parse(json)!;
     }
-}
+}