现有的webapi一般都基于JSON的格式来处理数据，由于JSON是一个文本类的序列化协议所以在性能上自然就相对低效一些。在.net中常用Newtonsoft.Json是最常用的组件，由于提供简便基于完整的json的String方法使用起来非常方便；但也正是这原因导致Newtonsoft.Json在性能上一直被说慢，虽然Newtonsoft.Json提供Stream的方式来处理JSON不过想复用writer和reader还是需要一些应用技巧。如果需要在网络通讯中应用JSON,那在这里介绍一下SpanJson这个组件，并通过一些测试来讲述如何使用它。
SpanJson介绍
SpanJson是一个性能相对不错的JSON组件，组件直接提供了byte[]和stream两种操作方式，而这两种方式非常适合在构建自有网络通讯上使用。通过这些基础的字节和流结构来处理可以相对降低一个大string的开销。不过这个组件的热度并不高，完善成度暂还不如Newtonsoft.Json,不过asp.net core 在FrameworkBenchmarks测试上已经引入。可以尝试一下使用，组件开源地址： https://github.com/Tornhoof/SpanJson (本地下载)
性能测试
组件提供的方法相对比较少，从设计上来说更多是针对通讯方面的支持。基于Stream的序列化可以直接挂载在NetStream上，这样可以节省数据复制带来的开销。不过反序列化不能直接在有混合数据的Stream上进行，这或多或少有些可惜。从issues的解答来看作者也不太愿意在混合数据流上进行调整。接下来针对bytes和Stream使用进行一个性能测试，而Stream则采用一个可复用池的设计
MemoryStream 池的设计
public class MemoryStreamPool { private static System.Collections.Concurrent.ConcurrentStack<JsonMemoryStream> mPool = new System.Collections.Concurrent.ConcurrentStack<JsonMemoryStream>(); public static Stream Pop() { if (!mPool.TryPop(out JsonMemoryStream result)) { result = new JsonMemoryStream(1024 * 32); } return result; } public class JsonMemoryStream : MemoryStream { public JsonMemoryStream(int size) : base(size) { } protected override void Dispose(bool disposing) { MemoryStreamPool.Push(this); } } private static void Push(JsonMemoryStream stream) { stream.Position = 0; stream.SetLength(0); mPool.Push(stream); } }
测试内容
测试的方式主要针对一个简单的对象和一个对象列表，然后在不同线程下bytes和Stream pool这两种方式的性能差别;压测的线程数据分别是1,2,4,8,16,24,32，每次测试执行的总数是100万次，然后统计出执行需要的时间和并发量。 测试代码:
public class Bytes_JSON : BeetleX.Benchmark.BenchmarkBase { protected override void OnTest() { while (Increment()) { var data = SpanJson.JsonSerializer.NonGeneric.Utf8.Serialize(DataHelper.Defalut.Employees[0]); var employees = SpanJson.JsonSerializer.Generic.Utf8.Deserialize<Employee>(data); } } } public class StreamPool_JSON : BeetleX.Benchmark.BenchmarkBase { protected override void OnTest() { RunTest(); } private async void RunTest() { while (Increment()) { using (Stream stream = MemoryStreamPool.Pop()) { await SpanJson.JsonSerializer.NonGeneric.Utf8.SerializeAsync(DataHelper.Defalut.Employees[0], stream); stream.Position = 0; var employees = await SpanJson.JsonSerializer.Generic.Utf8.DeserializeAsync<Employee>(stream); } } } } public class Bytes_JSON_List : BeetleX.Benchmark.BenchmarkBase { protected override void OnTest() { while (Increment()) { var data = SpanJson.JsonSerializer.NonGeneric.Utf8.Serialize(DataHelper.Defalut.Employees); var employees = SpanJson.JsonSerializer.Generic.Utf8.Deserialize<List<Employee>>(data); } } } public class StreamPool_JSON_List : BeetleX.Benchmark.BenchmarkBase { protected override void OnTest() { RunTest(); } private async void RunTest() { while (Increment()) { using (Stream stream = MemoryStreamPool.Pop()) { await SpanJson.JsonSerializer.NonGeneric.Utf8.SerializeAsync(DataHelper.Defalut.Employees, stream); stream.Position = 0; var employees = await SpanJson.JsonSerializer.Generic.Utf8.DeserializeAsync<List<Employee>>(stream); } } } }
测试结果
C:\Users\Administrator\Desktop\json_test>dotnet JsonSample.dll
BeetleX.Benchmark [0.5.4.0] Copyright ? ikende.com 2019
EMail:henryfan@msn.com
Github:https://github.com/ikende
-------------------------------------------------------------------------------
|Name | Round| Threads| Count| Use time(s)| Sec|
-------------------------------------------------------------------------------
|Bytes_JSON | 1| 1| 1000000| 5.57|179580|
-------------------------------------------------------------------------------
|StreamPool_JSON | 1| 1| 1000000| 5.44|183898|
-------------------------------------------------------------------------------
|Bytes_JSON_List | 1| 1| 1000000| 43.01| 23248|
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|StreamPool_JSON_List | 1| 1| 1000000| 42.75| 23391|
-------------------------------------------------------------------------------
|Bytes_JSON | 1| 2| 1000000| 2.81|355990|
-------------------------------------------------------------------------------
|StreamPool_JSON | 1| 2| 1000000| 2.95|338969|
-------------------------------------------------------------------------------
|Bytes_JSON_List | 1| 2| 1000000| 23.16| 43180|
-------------------------------------------------------------------------------
|StreamPool_JSON_List | 1| 2| 1000000| 22.4| 44650|
-------------------------------------------------------------------------------
|Bytes_JSON | 1| 4| 1000000| 1.51|661246|
-------------------------------------------------------------------------------
|StreamPool_JSON | 1| 4| 1000000| 1.57|636130|
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|Bytes_JSON_List | 1| 4| 1000000| 13.35| 74915|
-------------------------------------------------------------------------------
|StreamPool_JSON_List | 1| 4| 1000000| 11.97| 83508|
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|Bytes_JSON | 1| 8| 1000000| .83|1199453|
--------------------------------------------------------------------------------
|StreamPool_JSON | 1| 8| 1000000| .88|1142495|
--------------------------------------------------------------------------------
|Bytes_JSON_List | 1| 8| 1000000| 9.24|108228|
-------------------------------------------------------------------------------
|StreamPool_JSON_List | 1| 8| 1000000| 6.75|148132|
-------------------------------------------------------------------------------
|Bytes_JSON | 1| 16| 1000000| .56|1795910|
--------------------------------------------------------------------------------
|StreamPool_JSON | 1| 16| 1000000| .74|1344851|
--------------------------------------------------------------------------------
|Bytes_JSON_List | 1| 16| 1000000| 7.67|130424|
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|StreamPool_JSON_List | 1| 16| 1000000| 4.61|216860|
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|Bytes_JSON | 1| 24| 1000000| .54|1849769|
--------------------------------------------------------------------------------
|StreamPool_JSON | 1| 24| 1000000| .73|1361382|
--------------------------------------------------------------------------------
|Bytes_JSON_List | 1| 24| 1000000| 7.61|131373|
-------------------------------------------------------------------------------
|StreamPool_JSON_List | 1| 24| 1000000| 4.7|212779|
-------------------------------------------------------------------------------
|Bytes_JSON | 1| 32| 1000000| .55|1825484|
--------------------------------------------------------------------------------
|StreamPool_JSON | 1| 32| 1000000| .75|1339050|
--------------------------------------------------------------------------------
|Bytes_JSON_List | 1| 32| 1000000| 8.01|124885|
-------------------------------------------------------------------------------
|StreamPool_JSON_List | 1| 32| 1000000| 5.21|192038|
-------------------------------------------------------------------------------
Test completed!
总结