从 appsettings.json 读取 JSON 对象 [英] Reading a JSON object from appsettings.json

问题描述

TL;DR:如何从 appsettings.json 读取复杂的 JSON 对象?

TL;DR: How do I read a complex JSON object from appsettings.json?

我有一个具有多种类型配置值的 .NET Core 2.x 应用程序.appsettings.json 看起来像下面的代码片段，我试图将 ElasticSearch:MyIndex:mappings 的值作为单个字符串或 JSON 对象读取.

I have a .NET Core 2.x application with multiple types of configuration values. appsettings.json looks like the snippet below and I am trying to read the value of ElasticSearch:MyIndex:mappings as a single string or JSON object.

{
"ConnectionStrings": {
    "redis": "localhost"
},
"Logging": {
    "IncludeScopes": false,
    "Debug": {
        "LogLevel": {
            "Default": "Warning"
        }
    },
    "Console": {
        "LogLevel": {
            "Default": "Warning"
        }
    }
},
"ElasticSearch": {
    "hosts": [ "http://localhost:9200" ],
    "MyIndex": {
        "index": "index2",
        "type": "mytype",
        "mappings": {
            "properties": {
                "property1": {
                    "type": "string",
                    "index": "not_analyzed"
                },
                "location": {
                    "type": "geo_point"
                },
                "code": {
                    "type": "string",
                    "index": "not_analyzed"
                }
            }
        }
    }
}
}

通过调用 Configuration.GetValue("ElasticSearch:MyIndex:index")，我可以毫无问题地读取简单的配置值(键:值对).

I am able to read the simple config values (key:value pairs) without issue by calling Configuration.GetValue<string>("ElasticSearch:MyIndex:index").

Configuration.GetSectionConfiguration.GetSection("ElasticSearch:MyIndex:mappings").Value 给我一个 null 的 Value 值.

Configuration.GetSection Configuration.GetSection("ElasticSearch:MyIndex:mappings").Value gives me a null value for Value.

Configuration.GetValueConfiguration.GetValue("ElasticSearch:MyIndex:mappings") 也返回空值.这对我来说很有意义，因为基于上述尝试，该部分具有空值.

Configuration.GetValue Configuration.GetValue<string>("ElasticSearch:MyIndex:mappings") also returns a null value. This makes sense to me as the section has a null value based on the above attempt.

Configuration.GetValueConfiguration.GetValue("ElasticSearch:MyIndex:mappings") 也返回一个空值.出于与上述相同的原因，这对我来说也很有意义.

Configuration.GetValue Configuration.GetValue<JToken>("ElasticSearch:MyIndex:mappings") also returns a null value. This makes sense to me as well for the same reason as above.

推荐答案

最终的解决方案比我最初尝试的任何方法都要简单得多:将 appsettings.json 与任何其他 JSON 格式的文件一样读取.

The solution ended up being much simpler than anything I was initially trying: read appsettings.json as any other JSON formatted file.

JToken jAppSettings = JToken.Parse(
  File.ReadAllText(Path.Combine(Environment.CurrentDirectory, "appsettings.json"))
);

string mapping = jAppSettings["ElasticSearch"]["MyIndex"]["mappings"];

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