无缓冲串在内存中写入JSON到流 [英] Writing JSON to a stream without buffering the string in memory

问题描述

我想通过建立文档了明确写JSON到流。例如：

I would like to write JSON to a Stream by building the document up explicitly. For example:

var stream = ...;
var writer = new JsonWriter(stream);

writer.BeginArray();
{
  writer.BeginObject();
  {
    writer.String("foo");
    writer.Number(1);
    writer.String("bar");
    writer.Number(2.3);
  }
  writer.EndObject();
}
writer.EndArray();

这将产生：

[
  {
    "foo": 1,
    "bar": 2.3
  }
]

这种方法的好处是，没有什么需要在存储器中进行缓冲。在我的情况，我写了很多的JSON流中。解决方案如这个涉及创建你在内存中的所有对象，然后将它们连载到一个大的字符串在内存中，然后最后写该字符串流和垃圾收集，大概从蕙。我想保持我的记忆中使用低，写出元素，而从另一个文件/数据库/等读取数据流。

The benefit of this approach is that nothing needs to be buffered in memory. In my situation, I'm writing quite a lot of JSON to the stream. Solutions such as this one involve creating all your objects in memory, then serialising them to a large string in memory, then finally writing this string to the stream and garbage collecting, probably from the LOH. I want to keep my memory use low, writing out elements while reading data from another file/DB/etc stream.

这种方法是通过 rapidjson库可在C ++中。

This kind of approach is available in C++ via the rapidjson library.

我已搜索周围公平一点，这和还没有找到一个解决方案。

I've searched around a fair bit for this and haven't found a solution.

推荐答案

原来我需要谷歌的时间长一点。

Turns out I needed to Google for a bit longer.

JSON.NET并通过其<一个确实支持该href="http://james.newtonking.com/projects/json/help/index.html?topic=html/WriteJsonWithJsonTextWriter.htm"相对=nofollow> JsonWriter 类。

JSON.NET does indeed support this via its JsonWriter class.

我的例子是这样写：

Stream stream = ...;

using (var streamWriter = new StreamWriter(stream))
using (var writer = new JsonTextWriter(streamWriter))
{
    writer.Formatting = Formatting.Indented;

    writer.WriteStartArray();
    {
        writer.WriteStartObject();
        {
            writer.WritePropertyName("foo");
            writer.WriteValue(1);
            writer.WritePropertyName("bar");
            writer.WriteValue(2.3);
        }
        writer.WriteEndObject();
    }
    writer.WriteEndArray();
}

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