在 .Net 3.1 中 System.Text.Json 中没有等价物，所以我们必须自己推出。这是一种可能的IEqualityComparer<JsonElement>：
public class JsonElementComparer : IEqualityComparer<JsonElement>
{
public JsonElementComparer() : this(-1) { }
public JsonElementComparer(int maxHashDepth) => this.MaxHashDepth = maxHashDepth;
int MaxHashDepth { get; } = -1;
#region IEqualityComparer<JsonElement> Members
public bool Equals(JsonElement x, JsonElement y)
{
if (x.ValueKind != y.ValueKind)
return false;
switch (x.ValueKind)
{
case JsonValueKind.Null:
case JsonValueKind.True:
case JsonValueKind.False:
case JsonValueKind.Undefined:
return true;
// Compare the raw values of numbers, and the text of strings.
// Note this means that 0.0 will differ from 0.00 -- which may be correct as deserializing either to `decimal` will result in subtly different results.
// Newtonsoft's JValue.Compare(JTokenType valueType, object? objA, object? objB) has logic for detecting "equivalent" values,
// you may want to examine it to see if anything there is required here.
// https://github.com/JamesNK/Newtonsoft.Json/blob/master/Src/Newtonsoft.Json/Linq/JValue.cs#L246
case JsonValueKind.Number:
return x.GetRawText() == y.GetRawText();
case JsonValueKind.String:
return x.GetString() == y.GetString(); // Do not use GetRawText() here, it does not automatically resolve JSON escape sequences to their corresponding characters.
case JsonValueKind.Array:
return x.EnumerateArray().SequenceEqual(y.EnumerateArray(), this);
case JsonValueKind.Object:
{
// Surprisingly, JsonDocument fully supports duplicate property names.
// I.e. it's perfectly happy to parse {"Value":"a", "Value" : "b"} and will store both
// key/value pairs inside the document!
// A close reading of https://www.rfc-editor.org/rfc/rfc8259#section-4 seems to indicate that
// such objects are allowed but not recommended, and when they arise, interpretation of
// identically-named properties is order-dependent.
// So stably sorting by name then comparing values seems the way to go.
var xPropertiesUnsorted = x.EnumerateObject().ToList();
var yPropertiesUnsorted = y.EnumerateObject().ToList();
if (xPropertiesUnsorted.Count != yPropertiesUnsorted.Count)
return false;
var xProperties = xPropertiesUnsorted.OrderBy(p => p.Name, StringComparer.Ordinal);
var yProperties = yPropertiesUnsorted.OrderBy(p => p.Name, StringComparer.Ordinal);
foreach (var (px, py) in xProperties.Zip(yProperties))
{
if (px.Name != py.Name)
return false;
if (!Equals(px.Value, py.Value))
return false;
}
return true;
}
default:
throw new JsonException(string.Format("Unknown JsonValueKind {0}", x.ValueKind));
}
}
public int GetHashCode(JsonElement obj)
{
var hash = new HashCode(); // New in .Net core: https://docs.microsoft.com/en-us/dotnet/api/system.hashcode
ComputeHashCode(obj, ref hash, 0);
return hash.ToHashCode();
}
void ComputeHashCode(JsonElement obj, ref HashCode hash, int depth)
{
hash.Add(obj.ValueKind);
switch (obj.ValueKind)
{
case JsonValueKind.Null:
case JsonValueKind.True:
case JsonValueKind.False:
case JsonValueKind.Undefined:
break;
case JsonValueKind.Number:
hash.Add(obj.GetRawText());
break;
case JsonValueKind.String:
hash.Add(obj.GetString());
break;
case JsonValueKind.Array:
if (depth != MaxHashDepth)
foreach (var item in obj.EnumerateArray())
ComputeHashCode(item, ref hash, depth+1);
else
hash.Add(obj.GetArrayLength());
break;
case JsonValueKind.Object:
foreach (var property in obj.EnumerateObject().OrderBy(p => p.Name, StringComparer.Ordinal))
{
hash.Add(property.Name);
if (depth != MaxHashDepth)
ComputeHashCode(property.Value, ref hash, depth+1);
}
break;
default:
throw new JsonException(string.Format("Unknown JsonValueKind {0}", obj.ValueKind));
}
}
#endregion
}
如下使用：
var comparer = new JsonElementComparer();
using var doc1 = System.Text.Json.JsonDocument.Parse(referenceJson);
using var doc2 = System.Text.Json.JsonDocument.Parse(resultJson);
Assert.IsTrue(comparer.Equals(doc1.RootElement, doc2.RootElement));
注意事项：
演示小提琴here.