問(wèn)題描述

我有一個(gè) JSON 對(duì)象流，看起來(lái)有點(diǎn)像這樣:

{...}{...}{...}{...}...

所以基本上是一個(gè)沒(méi)有任何分隔符的 JSON 對(duì)象的串聯(lián)列表.使用 JSON.NET 將它們反序列化為 IEnumerable<T> 的正確方法是什么?目前我嘗試了類(lèi)似

var serializer = new JsonSerializer();序列化程序.CheckAdditionalContent = false;使用 (var reader = new StreamReader(stream))使用 (var jsonReader = new JsonTextReader(reader)) {reader.SupportMultipleContent = true;閱讀器.Read();而(reader.TokenType！= JsonToken.None){yield return serializer.Deserialize(reader);}}

但這失敗了

Newtonsoft.Json.JsonSerializationException:反序列化對(duì)象時(shí)出現(xiàn)意外令牌:EndObject.路徑 ''，第 1 行，位置 55.在 Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader 閱讀器，類(lèi)型 objectType，JsonContract 合同，JsonProperty 成員，JsonContainerContract containerContract，JsonProperty containerMember，對(duì)象現(xiàn)有值)在 Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader 閱讀器，類(lèi)型 objectType，布爾 checkAdditionalContent)在 Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader 閱讀器，類(lèi)型 objectType)在 Newtonsoft.Json.JsonSerializer.Deserialize[T](JsonReader 閱讀器)

顯然我需要在 Deserialize 調(diào)用之后移動(dòng)閱讀器，但我該怎么做呢?

我認(rèn)為如果你稍微改變你的循環(huán)，一切都應(yīng)該工作:

public IEnumerableReadJson(流流){var serializer = new JsonSerializer();使用 (var reader = new StreamReader(stream))使用 (var jsonReader = new JsonTextReader(reader)){jsonReader.SupportMultipleContent = true;而(jsonReader.Read()){yield return serializer.Deserialize<TResult>(jsonReader);}}}

請(qǐng)注意，當(dāng)傳遞給此方法的 Stream 處于打開(kāi)狀態(tài)時(shí)，您必須遍歷 IEnumerable:

using (var stream =/* some stream */){IEnumerable<MyClass>結(jié)果 = ReadJson<MyClass>(流);foreach(結(jié)果中的變量項(xiàng)){Console.WriteLine(item.MyProperty);}}

示例: https://dotnetfiddle.net/Y2FLuK

JsonNet 站點(diǎn)上的示例:使用 JsonReader 讀取多個(gè)片段p>

I have a stream of JSON objects that looks somewhat like this:

{...}{...}{...}{...}...

So basically a concatenated list of JSON objects without any separator. What's the proper way to deserialize those into an IEnumerable<T> using JSON.NET? At the moment I tried something like

var serializer = new JsonSerializer();
serializer.CheckAdditionalContent = false;

using (var reader = new StreamReader(stream))
using (var jsonReader = new JsonTextReader(reader)) {
    reader.SupportMultipleContent = true;
    reader.Read();
    while (reader.TokenType != JsonToken.None) {
        yield return serializer.Deserialize<TResult>(reader);
    }
}

But this fails with

Newtonsoft.Json.JsonSerializationException: Unexpected token while deserializing object: EndObject. Path '', line 1, position 55.
  at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue)
  at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent)
  at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType)
  at Newtonsoft.Json.JsonSerializer.Deserialize[T](JsonReader reader)

Obviously I need to move the reader after the Deserialize call, but how do I do this?

I think if you change your loop around slightly everything should work:

public IEnumerable<TResult> ReadJson<TResult>(Stream stream)
{
    var serializer = new JsonSerializer();

    using (var reader = new StreamReader(stream))
    using (var jsonReader = new JsonTextReader(reader))
    {
        jsonReader.SupportMultipleContent = true;

        while (jsonReader.Read())
        {
            yield return serializer.Deserialize<TResult>(jsonReader);
        }
    }
}

Note that you must iterate over the IEnumerable<TResult> while the Stream passed to this method is open:

using (var stream = /* some stream */)
{
    IEnumerable<MyClass> result = ReadJson<MyClass>(stream);

    foreach (var item in result)
    {
        Console.WriteLine(item.MyProperty);
    }
}

Example: https://dotnetfiddle.net/Y2FLuK

Sample on JsonNet site: Read Multiple Fragments With JsonReader

這篇關(guān)于使用 JSON.NET 解析 JSON 對(duì)象流的正確方法是什么?的文章就介紹到這了，希望我們推薦的答案對(duì)大家有所幫助，也希望大家多多支持html5模板網(wǎng)！