Newtonsoft.Json - 反序列化大对象时出现内存异常

问题描述

我有一个问题反序列化约1GB的JSON文件的问题。当我运行以下代码时，我得到了一个内存异常：

  using（FileStream sr = new FileStream（myFile.json ，FileMode.Open，FileAccess.Read））
 {
 using（StreamReader reader = new StreamReader（sr））
 {
 using（JsonReader jsReader = new JsonTextReader（reader） ）
 {
 JsonSerializer serializer = new JsonSerializer（）; 
 dataObject = serializer.Deserialize< T>（jsReader）; 
} 
} 
} 
  

异常抛出

  Newtonsoft.Json.Linq.JTokenWriter.WriteValue（Int64值）
  

序列化效果很好，这里是我使用的代码

  using（StreamWriter reader = new StreamWriter（myFile.json））
 {
 using（JsonReader jsWriter = new JsonWriter（reader））
 {
 JsonTextWriter jsonWriter = new JsonTextWriter（jsWriter）{Formatting = Formatting.Indented}; 
 JsonSerializer ser = new JsonSerializer（）; 
 ser.Serialize（jsonWriter，dataObject，dataObject.GetType（））; 
 jsonWriter.Flush（）; 
} 
}} 
  

我在反序列化中做错了吗？你可以帮助建议一种反序列化大json对象的方法吗？

谢谢

解决方案

根据，您的方法必须工作（因为你通过流读取它应该使你的文件的部分）。我不知道为什么你的代码不起作用。

但是你可以尝试另一种方法，这在下一篇文章中描述 -

I have a problem deserializing a JSON file of about 1GB. When I run the following code I get an out of memory exception:

using (FileStream sr = new FileStream("myFile.json", FileMode.Open, FileAccess.Read))
{
  using (StreamReader reader = new StreamReader(sr))
  {
    using (JsonReader jsReader = new JsonTextReader(reader))
    {
      JsonSerializer serializer = new JsonSerializer();
      dataObject = serializer.Deserialize<T>(jsReader);
    }
  }
}

the exception is thrown by

Newtonsoft.Json.Linq.JTokenWriter.WriteValue(Int64 value)

The serialization works well, here is the code I'm using

using (StreamWriter reader = new StreamWriter("myFile.json"))
{
   using (JsonReader jsWriter = new JsonWriter(reader))
   {
      JsonTextWriter jsonWriter = new JsonTextWriter(jsWriter) { Formatting = Formatting.Indented };
      JsonSerializer ser = new JsonSerializer();
      ser.Serialize(jsonWriter, dataObject, dataObject.GetType());
      jsonWriter.Flush();
    }
}}

Am I doing something wrong in the deserialization? Can you help suggesting a way to deserialize big json object?

Thanks

解决方案

According to Newtonsoft.Json Performance Tips your approach has to work (because you read via stream and it should make portion from your file). I can't figure out why your code doesn't work.

But you can try another approach, that was described in the next article - Parsing Big Records with Json.NET

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