Json.Net学习笔记(四) Json对象的读写

为了手动读写Json对象，Json.Net提供了JsonReader 和 JsonWriter这两个抽象类及其相应的派生类:

1.JsonTextReader 和 JsonTextWriter

用来读写Json对象的文本，JsonTextWriter 有大量设置去控制Json对象的格式。

测试：

            //写操作

            StringBuilder sb = new StringBuilder();
            StringWriter sw = new StringWriter(sb);
            using (JsonWriter jsonWriter = new JsonTextWriter(sw))
            {               

                jsonWriter.Formatting = Formatting.Indented;
                jsonWriter.WriteStartObject();
                
                jsonWriter.WritePropertyName("CPU");
                jsonWriter.WriteValue("Intel");
                jsonWriter.WritePropertyName("PSU");
                jsonWriter.WriteValue("500W");
                jsonWriter.WritePropertyName("Drives");

                jsonWriter.WriteStartArray();
                jsonWriter.WriteValue("DVD read/writer");
                jsonWriter.WriteComment("(broken)");
                jsonWriter.WriteValue("500 gigabyte hard drive");
                jsonWriter.WriteValue("200 gigabype hard drive");

                jsonWriter.WriteEndArray();
                jsonWriter.WriteEndObject();

            }

            Console.WriteLine(sb.ToString());

输出结果：

{
  "CPU": "Intel",
  "PSU": "500W",
  "Drives": [
    "DVD read/writer"
    /*(broken)*/,
    "500 gigabyte hard drive",
    "200 gigabype hard drive"
  ]
}

      //读操作

     TextReader txtReader = new StringReader(sb.ToString());
            using (JsonReader jsonReader = new JsonTextReader(txtReader))
            {
                string readResult = "{\n";
                while (jsonReader.Read())
                {
                    if (jsonReader.TokenType == JsonToken.PropertyName)
                    {
                        readResult += (string)jsonReader.Value + ":";
                    }
                    else if (jsonReader.TokenType == JsonToken.String)
                    {
                        readResult += (string)jsonReader.Value + "\n";
                    }
                    else if (jsonReader.TokenType == JsonToken.StartArray)
                    {
                        readResult += "[\n";
                        while (jsonReader.Read())
                        {
                            if (jsonReader.TokenType == JsonToken.EndArray)
                            {
                                readResult = readResult.Remove(readResult.Length - 2, 1);
                                readResult += "]\n";
                                break;
                            }
                            if (jsonReader.TokenType == JsonToken.String)
                                readResult += (string)jsonReader.Value + ",\n";
                            else if (jsonReader.TokenType == JsonToken.Comment)
                                readResult += "/*" + (string)jsonReader.Value + "*/,\n";
                        }
                    }
                }
                readResult += "}\n";
                Console.WriteLine(readResult);

             }

2.JTokenReader and JTokenWriter

JTokenReader and JTokenWriter是读写Linq to Json对象的，他们存在于Newtonsoft.Json.Linq名字空间中

         JObject o = new JObject(
                        new JProperty("Name", "ZhangSan"),
                        new JProperty("BirthDay", new DateTime(1985, 11, 27)));

            JsonSerializer serializer = new JsonSerializer();
            Person person = (Person)serializer.Deserialize(new JTokenReader(o), typeof(Person));
            Console.WriteLine(person.Name);//输出ZhangSan