System.Text.Json

在.NET Core 3.0中加入了对JSON的内置支持。

序列化

using System.Text.Json;
using System.Text.Json.Serialization;

JsonSerializer.Serialize(DemoEntity)

读取与写入

// 读取
var str = File.ReadAllText(file);
var data = JsonSerializer.DeserializeObject<List<Demo>>(str);

// 写入
str = JsonSerializer.Serialize(DemoEntity);
File.WriteAllText(file, str);

时间格式化

/// <summary>
/// 自定义时间转化器
/// </summary>
public class DateTimeConverterUsingDateTimeParse : JsonConverter<DateTime>
{
    public override DateTime Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
    {
        return DateTime.Parse(reader.GetString());
    }
    public override void Write(Utf8JsonWriter writer, DateTime value, JsonSerializerOptions options)
    {
        writer.WriteStringValue(value.ToString("yyyyMMddHHmmss"));
    }
}

JsonSerializerOptions options = new JsonSerializerOptions();
options.Converters.Add(new DateTimeConverterUsingDateTimeParse());
string jsonString = JsonSerializer.Serialize(data, options);

序列化扩展

/// <summary>
/// 小驼峰格式反序列化。
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="str"></param>
/// <returns></returns>
public static T DeserializeWithCamel<T>(string str)
{
    if (str != null)
    {
        // 小驼峰序列化
        var setting = new JsonSerializerOptions
        {
            PropertyNamingPolicy = JsonNamingPolicy.CamelCase
        };
        return JsonSerializer.Deserialize<T>(str, setting);
        // Newtonsoft
        var setting = new JsonSerializerSettings
        {
            ContractResolver = new Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver(),
        };
        return JsonConvert.DeserializeObject<T>(str, setting);
    }
    else
    {
        return default(T);
    }
}
/// <summary>
/// 小驼峰格式序列化。
/// </summary>
/// <typeparam name="T">对象类型</typeparam>
/// <param name="entity">类型对象</param>
/// <returns></returns>
public static string SerializeWithCamel<T>(T entity)
{
    // 小驼峰序列化
    var setting = new JsonSerializerOptions
    {
        PropertyNamingPolicy = JsonNamingPolicy.CamelCase
    };
    return JsonSerializer.Serialize(entity, setting);
    // Newtonsoft
    var setting = new JsonSerializerSettings
    {
        ContractResolver = new Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver(),
    };
    return JsonConvert.SerializeObject(entity, setting);
}

格式化json字符串

.NET Core版本

/// <summary>
/// 格式化JSON字符串
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="obj"></param>
/// <returns></returns>
public static string ConvertJsonString<T>(T obj)
{
    if (obj != null)
    {
        var setting = new JsonSerializerOptions
        {
            WriteIndented = true,
        };
        return JsonSerializer.Serialize(obj, setting);
    }
    return string.Empty;
}

Newtonsoft版本

using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;
/// <summary>
/// 格式化JSON字符串
/// </summary>
/// <typeparam name="T">对象类型</typeparam>
/// <param name="obj">类型对象</param>
/// <returns></returns>
public static string ConvertJsonString<T>(T obj)
{
    if (obj != null)
    {
        JsonSerializer serializer = new JsonSerializer();
        StringWriter writer = new StringWriter();
        JsonTextWriter jwriter = new JsonTextWriter(writer)
        {
            Formatting = Formatting.Indented,
            Indentation = 4,
            IndentChar = ' ',
        };
        serializer.Serialize(jwriter, obj);
        return writer.ToString();
    }
    return string.Empty;
}

若是序列化后的字符串，不知道相应的对象类型，可以如下转换：

/// <summary>
/// 格式化JSON字符串
/// </summary>
/// <param name="string">序列化后的字符串</param>
/// <returns></returns>
public static string ConvertJsonString(string str)
{
    try
    {
        JsonSerializer serializer = new JsonSerializer();
        TextReader tr = new StringReader(str);
        JsonTextReader jtr = new JsonTextReader(tr);
        object obj = serializer.Deserialize(jtr);
        if (obj != null)
        {
            StringWriter writer = new StringWriter();
            JsonTextWriter jwriter = new JsonTextWriter(writer)
            {
                Formatting = Formatting.Indented,
                Indentation = 4,
                IndentChar = ' ',
            };
            serializer.Serialize(jwriter, obj);
            return writer.ToString();
        }
    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.Message);
    }
    return str;
}

反序列化

Json

Newtonsoft

public static T JsonToObject<T>(string jsonStr)
{
    return JsonConvert.DeserializeObject<T>(jsonStr);
}