What’s next for System.Text.Json in .NET 5.0?

You can install .NET 5.0 for your project requirements is in .NET 5, This provides you System.Text.Json right out of the box, without any other pre-requisites.

If your project requirements in .NET Core 3.x or .NET Framework and .NET Standard compatible library so you can install the latest package System.Text.JsonNuget Package.

If your project requirements in .NET Core 3.x or .NET Framework and .NET Standard compatible library so you can install the latest package System.Text.JsonNuget Package.

The System.Text.Json is the built-in JavaScript Object Notation (JSON) serialization library in .NET for converting from .NET object types to a JSON string, and vice versa, supporting UTF-8 text encoding. JsonSerializer library was first added in .NET Core 3.0. It’s a popular type in the library JsonSerializer, which provides the highest level of functionality of processing JSON data.

Example:

usingSystem.Text.Json;

                    namespaceJsonLibary
                    {
                    classProgram
                        {
                    
                         staticvoid Main(string[] args)
                            {
                                Some obj = new() { Message = "Welcome to Visual Studio" };
                                stringjson = JsonSerializer.Serialize(obj);
                                Console.WriteLine(json);
                                Some secondObject = JsonSerializer.Deserialize("{}");
                                Console.WriteLine(secondObject.Message);   
                            }
                         publicclassSome
                            {
                                publicstring Message { get; set; }
                            }
                        }
                    }

Figure:Output Screen

When you are using .NET Core 3.0, the deserializing number types encoded as JSON strings were not supported by default. You can add a custom converter for each applicable number type which would take control of the serialization and deserialization of the type, and include logic to handle quoted numbers.

There is an opt-in feature to support serializing and deserializing quoted numbers, and named floating-point literals like Nan, Infinity, and, -Infinity in .NET 5.0

When you serializing in .NET Core 3.x, there was only possible to ignore the null value for reference or nullable value-typed properties, the JsonSerilizerOptions.IgnoreNullValues setting was only applicable across an entire input object graph. We have to add support to ignore default values for non-nullable value types, such as int and float. Further, we are now possible to cherry-pick properties and fields to be ignored when default.

Example

var options = newJsonSerializerOptions
                      {
                           DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingDefault
                      };
              
                         varobj = newyourClass();
                         stringjson = JsonSerializer.Serialize(obj, options);
                         Console.WriteLine(json);
              
               publicclassyourClass
                      {
                         publicintyourInt{ get; set; }
              
                          [JsonIgnore(Condition = JsonIgnoreCondition.Never)]
                          publicboolyourBool{ get; set; }
              
                          publicstringyourString{ get; set; }
                      }

Here we can see that we have passed the default value JsonIgnoreCondition.WhenWritingDefault in the JsonSerializerOptions class and this class declared with options variable, the JsonIgnoreCondition.WhenWritingDefault is ignoring only null values, but not default values.

After, we put the class name yourClass is declared with a new keyword and it identify with theobj variable.

Then, the obj and options value pass in the JsonSerializer.Serialize method with defined by JSON variable, print the JSON variable with console.WriteLine.

The JsonSerializerOptions coping the one instance to another instance,so we have added a copy constructor to JsonSerializerOptions which makes this easier for the user.

Example

JsonSerializerOptions opt = new()
                {
                    Handling = JsonNumberHandling.AllowReadingFromString,
                    ignoreCondition = JsonIgnoreCondition.WhenWritingNull,
                    Converters = { newJsonStringEnumConverter() }
                };
    JsonSerializerOptionsnewOpt = new(opt)
                {
                    Handling = JsonNumberHandling.Strict
                };
    
               Console.WriteLine(newOpt.Handling);
    
               Console.WriteLine(newOpt.ignoreCondition);
    
               Console.WriteLine(newOpt.Converters[0]);  

There are some common set of options when processing JSON data in web contexts is to use the camelCase naming policy. You specify case-insensitive matching when deserializing, and allow reading quoted numbers. You have to declare the JsonSerializerDefaults.Webenum value, and a new constructor that takes a JsonSerializerDefaults value, provide an easy way to reuse these options in a consistent way across multiple layers of an application.

Example

JsonSerializerOptionsserializerOptions = new (JsonSerializerDefaults.Web);

  Console.WriteLine(serializerOptions.PropertyNamingPolicy);
  
  Console.WriteLine(serializerOptions.PropertyNameCaseInsensitive);   
  
  Console.WriteLine(serializerOptions.Handling);

There is a major difference between .NET Core 3.1 and .NET 5, and we have improved performance in the following areas.

The significant improvements for large collections made by us. These improvements are characterized in much more detail at dotnet/runtime #2259.

The significant efforts to improve .NET performance in the TechEmpower JSON benchmark in .NET 5.0. The performance when observing work done within the serializer is now ~19% better.

There are most common issues with using JSON is a mismatch of naming conventions with .NET design guidelines. The camelCase is used in JSON properties and the PascalCase is used in .NET properties and fields.

When we write relatively large JSON strings using the writer directly, there is ~30% improvement.