使用 Json.NET 序列化时，如何应用重新映射所有属性名称的一般规则?

Question

将 Json 对象反序列化为 .Nettype时，如果字段名称不匹配，我发现你可以用[JsonProperty(PropertyName = "name")]来装饰type的属性

对于不匹配的几个属性来说，这很好，但是有没有办法设置约定或规则？

杰森

{
"Job": [
{
"Job #": "1",
"Job Type": "A",
}
]
}

C#

[JsonProperty(PropertyName = "Job Type")]
public string JobType { get; set; }
[JsonProperty(PropertyName = "Job #")]
public string JobNumber { get; set; }

我有很多字段使用相似的名称，我想弄清楚的是，有没有办法告诉设置一个规则来始终删除空格(例如：Job Type -> JobType)并将#替换为Number(例如：Job # -> JobNumber)？

看起来自定义ContractResolver可能是唯一的解决方案，但我似乎无法弄清楚如何使用它来拔出空格并将"#"替换为"数字"。有人有参考示例吗？

或者，我希望有一个我忽略的很好的简单解决方案。

附言还接受更好的标题建议。

Answer 1

假设您使用的是 Json.NET 9.0.1 或更高版本，这可以通过自定义NamingStrategy来完成。 例如，这里有一个基于詹姆斯·牛顿-金的SnakeCaseNamingStrategy和StringUtils.ToSnakeCase()：

public class CustomNamingStrategy : NamingStrategy
{
public CustomNamingStrategy(bool processDictionaryKeys, bool overrideSpecifiedNames)
{
ProcessDictionaryKeys = processDictionaryKeys;
OverrideSpecifiedNames = overrideSpecifiedNames;
}
public CustomNamingStrategy(bool processDictionaryKeys, bool overrideSpecifiedNames, bool processExtensionDataNames)
: this(processDictionaryKeys, overrideSpecifiedNames)
{
ProcessExtensionDataNames = processExtensionDataNames;
}
public CustomNamingStrategy()
{
}
protected override string ResolvePropertyName(string name)
{
return SpaceWords(name);
}
enum WordState
{
Start,
Lower,
Upper,
NewWord
}
static string SpaceWords(string s)
{
// Adapted from StringUtils.ToSnakeCase()
// https://github.com/JamesNK/Newtonsoft.Json/blob/master/Src/Newtonsoft.Json/Utilities/StringUtils.cs#L191
// 
// Copyright (c) 2007 James Newton-King
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
char wordBreakChar = ' ';
if (string.IsNullOrEmpty(s))
{
return s;
}
StringBuilder sb = new StringBuilder();
WordState state = WordState.Start;
for (int i = 0; i < s.Length; i++)
{
if (s[i] == ' ')
{
if (state != WordState.Start)
{
state = WordState.NewWord;
}
}
else if (char.IsUpper(s[i]))
{
switch (state)
{
case WordState.Upper:
bool hasNext = (i + 1 < s.Length);
if (i > 0 && hasNext)
{
char nextChar = s[i + 1];
if (!char.IsUpper(nextChar) && nextChar != ' ')
{
sb.Append(wordBreakChar);
}
}
break;
case WordState.Lower:
case WordState.NewWord:
sb.Append(wordBreakChar);
break;
}
sb.Append(s[i]);
state = WordState.Upper;
}
else if (s[i] == wordBreakChar)
{
sb.Append(wordBreakChar);
state = WordState.Start;
}
else
{
if (state == WordState.NewWord)
{
sb.Append(wordBreakChar);
}
sb.Append(s[i]);
state = WordState.Lower;
}
}
sb.Replace("Number", "#");
return sb.ToString();
}
}

然后，您可以将其应用于您的类型，如下所示：

[JsonObject(NamingStrategyType = typeof(CustomNamingStrategy))]
public class RootObject
{
public string JobType { get; set; }
public string JobNumber { get; set; }
public int JobItemCount { get; set; }
public string ISOCode { get; set; }
public string SourceXML { get; set; }
}

生成的 JSON 将如下所示：

{
"Job Type": "job type",
"Job #": "01010101",
"Job Item Count": 3,
"ISO Code": "ISO 9000",
"Source XML": "c:temp.xml"
}

笔记：

• 如果希望策略应用于已通过JsonPropertyAttribute.PropertyName指定属性名称的属性，请设置NamingStrategy.OverrideSpecifiedNames == true。

要将命名策略

• 应用于所有类型而不是在每个对象上设置命名策略，可以在DefaultContractResolver.NamingStrategy中设置命名策略，然后在JsonSerializerSettings.ContractResolver中设置协定解析程序。

• 命名策略从 c# 属性名称映射到 JSON 属性名称，反之亦然。 因此，您需要插入空格而不是"拔掉它们"并将"数字"替换为"#"。 然后，协定解析程序缓存映射，并在反序列化期间完成反向查找。

Answer 2

是的，ContractResolver是要走的路。

问题是这些似乎只适用于从目标属性到源属性，即"JobType" -> "Job Type"，而不是您想要的相反方式。这使得解决方案比您想要的更片状。

首先我们制作ContractResolver，继承自DefaultContractResolver，因此除了我们要自定义的位外，一切正常：

public class JobContractResolver : DefaultContractResolver
{
protected override string ResolvePropertyName(string propertyName)
{
// first replace all capital letters with space then letter ("A" => " A"). This might include the first letter, so trim the result.
string result = Regex.Replace(propertyName, "[A-Z]", x => " " + x.Value).Trim();
// now replace Number with a hash
result = result.Replace("Number", "#");
return result;
}
}

然后在反序列化中，我们在JsonSerializerSettings中设置ContractResolver：

static void Main(string[] args)
{
string input = @"{""Job #"": ""1"", ""Job Type"": ""A""}";
var job1 = JsonConvert.DeserializeObject<Job1>(input, new JsonSerializerSettings
{
ContractResolver = new JobContractResolver()
});
Console.WriteLine("JobType: {0}", job1.JobType);
Console.WriteLine("JobNumber: {0}", job1.JobNumber);
}