由于.NET 6中JsonNode
没有Clone()
方法,因此最简单的复制方式可能是调用序列化程序的JsonSerializer.Deserialize<TValue>(JsonNode, JsonSerializerOptions)
扩展方法,将您的节点直接反序列化到另一个节点中。首先,引入以下扩展方法来复制或移动节点:
public static partial class JsonExtensions
{
public static TNode? CopyNode<TNode>(this TNode? node) where TNode : JsonNode => node?.Deserialize<TNode>();
public static JsonNode? MoveNode(this JsonArray array, int id, JsonObject newParent, string name)
{
var node = array[id];
array.RemoveAt(id);
return newParent[name] = node;
}
public static JsonNode? MoveNode(this JsonObject parent, string oldName, JsonObject newParent, string name)
{
parent.Remove(oldName, out var node);
return newParent[name] = node;
}
public static TNode ThrowOnNull<TNode>(this TNode? value) where TNode : JsonNode => value ?? throw new JsonException("Null JSON value");
}
现在,您的代码可以按照以下方式编写:
public static string concQuest(string input, string allQuest, string questId)
{
var inputObject = JsonNode.Parse(input).ThrowOnNull().AsObject();
var allQuestArray = JsonNode.Parse(allQuest).ThrowOnNull().AsArray();
concQuest(inputObject, allQuestArray, questId);
return inputObject.ToJsonString();
}
public static JsonNode? concQuest(JsonObject inputObject, JsonArray allQuestArray, string questId)
{
var node = allQuestArray.First(quest => quest!["id"]!.GetValue<string>() == questId);
return inputObject["quest"] = node.CopyNode();
}
或者,如果您不打算保留任务数组,您可以像这样将节点从数组移动到目标:
public static string concQuest(string input, string allQuest, string questId)
{
var inputObject = JsonNode.Parse(input).ThrowOnNull().AsObject();
var allQuestArray = JsonNode.Parse(allQuest).ThrowOnNull().AsArray();
concQuest(inputObject, allQuestArray, questId);
return inputObject.ToJsonString();
}
public static JsonNode? concQuest(JsonObject inputObject, JsonArray allQuestArray, string questId)
{
var (_, index) = allQuestArray.Select((quest, index) => (quest, index)).First(p => p.quest!["id"]!.GetValue<string>() == questId);
return allQuestArray.MoveNode(index, inputObject, "quest");
}
另外,你写道
由于我的json文件非常大(超过6MB),我担心可能会出现一些性能问题。
在这种情况下,我建议避免将JSON文件加载到 input
和 allQuest
字符串中,因为字符串大于85,000字节会进入 大对象堆,这可能会导致随后的性能降低。相反,可以直接从相关文件反序列化为 JsonNode
数组和对象,如下所示:
var questId = "2";
JsonArray allQuest;
using (var stream = new FileStream(allQuestFileName, new FileStreamOptions { Mode = FileMode.Open, Access = FileAccess.Read }))
allQuest = JsonNode.Parse(stream).ThrowOnNull().AsArray();
JsonObject input;
using (var stream = new FileStream(inputFileName, new FileStreamOptions { Mode = FileMode.Open, Access = FileAccess.Read }))
input = JsonNode.Parse(stream).ThrowOnNull().AsObject();
JsonExtensions.concQuest(input, allQuest, questId);
using (var stream = new FileStream(inputFileName, new FileStreamOptions { Mode = FileMode.Create, Access = FileAccess.Write }))
using (var writer = new Utf8JsonWriter(stream, new JsonWriterOptions { Indented = true }))
input.WriteTo(writer);
或者,如果你的应用程序是异步的,你可以这样做:
JsonArray allQuest;
await using (var stream = new FileStream(allQuestFileName, new FileStreamOptions { Mode = FileMode.Open, Access = FileAccess.Read, Options = FileOptions.Asynchronous }))
allQuest = (await JsonSerializer.DeserializeAsync<JsonArray>(stream)).ThrowOnNull();
JsonObject input;
await using (var stream = new FileStream(inputFileName, new FileStreamOptions { Mode = FileMode.Open, Access = FileAccess.Read, Options = FileOptions.Asynchronous }))
input = (await JsonSerializer.DeserializeAsync<JsonObject>(stream)).ThrowOnNull();
JsonExtensions.concQuest(input, allQuest, questId);
await using (var stream = new FileStream(inputFileName, new FileStreamOptions { Mode = FileMode.Create, Access = FileAccess.Write, Options = FileOptions.Asynchronous }))
await JsonSerializer.SerializeAsync(stream, input, new JsonSerializerOptions { WriteIndented = true });
注意:
演示 fiddles: