.Net Core如何读取Json配置文件

前言：在与传统的asp.net MVC项目相比,.net core项目在项目目录的文件结构上和功能上与前者都有很大的区别。例如：在.net core中使用Startup.cs取代Global.asax文件用于加载应用程序的配置和各种启动项。appsettings.json取代web.config文件用于存储应用程序所需的配置参数等等。。。

OK！步入正题,下面来说一下如何读取Json配置文件中的参数。

第一种:使用IConfiguration接口

我们先在appsettings.json中配置好数据库连接字符串,然后读取它

{  "Connection": {    "dbContent": "Data Source=.;Initial Catalog=test;User ID=sa;Password=123456"  },  "Logging": {    "LogLevel": {      "Default": "Information",      "Microsoft": "Warning",      "Microsoft.Hosting.Lifetime": "Information"    }  },  "AllowedHosts": "*"}

在控制器中注入IConfiguration接口

using System;using System.Collections.Generic;using System.Linq;using System.Threading.Tasks;using Microsoft.AspNetCore.Mvc;using Microsoft.Extensions.Configuration;namespace Read.json.Controllers{    [ApiController]    [Route("[controller]")]    public class ReadController : Controller    {        private IConfiguration _configuration;        public ReadController(IConfiguration configuration)        {            _configuration = configuration;        }        [HttpPost]        public async Task<string> ReadJson()        {            //读参            string conn = _configuration["Connection:dbContent"];            return "";        }    }}

当然也可以读取数组形式的json,一样的先在appsettings.json中写好配置参数，如下：

{  "Connection": {    "dbContent": "Data Source=.;Initial Catalog=test;User ID=sa;Password=123456"  },  //------------------------  "Content": [    {      "Trade_name": {        "test1": "小熊饼干",        "test2": "旺仔QQ糖",        "test3": "娃哈哈牛奶"      }    }  ],  //------------------------  "Logging": {    "LogLevel": {      "Default": "Information",      "Microsoft": "Warning",      "Microsoft.Hosting.Lifetime": "Information"    }  },  "AllowedHosts": "*"}

比如我们想读取test1

string commodity_test1 = _configuration["Content:0:Trade_name:test1"];

第二种：使用IOptions<T>来读取json配置文件

先把NuGet包导进项目：Microsoft.Extensions.Options.ConfigurationExtensions

首先在appsettings.json中添加节点如下

{  "Connection": {    "dbContent": "Data Source=.;Initial Catalog=test;User ID=sa;Password=123456"  },  //------------------------  "Content": [    {      "Trade_name": {        "test1": "小熊饼干",        "test2": "旺仔QQ糖",        "test3": "娃哈哈牛奶"      }    }  ],  //------------------------  "Logging": {    "LogLevel": {      "Default": "Information",      "Microsoft": "Warning",      "Microsoft.Hosting.Lifetime": "Information"    }  },  "AllowedHosts": "*",  //==============================  "Information": {    "school": {      "Introduce": {        "Name": "实验小学",        "Class": "中班",        "Number": "15人"      },      "Region": {        "Province": "湖北",        "City": "武汉",        "Area": "洪山区"      },      "Detailed_address": [        {          "Address": "佳园路207号"        }      ]    }  }  //==============================}

然和再建立一个与这个节点"相同"的类

using System;using System.Collections.Generic;using System.Linq;using System.Threading.Tasks;namespace Read.json{    public class Information    {        public School school { get; set; }    }    public class School    {        public Introduce Introduce { get; set; }        public Region Region { get; set; }        public List<Detailed_address> data { get; set; }    }    public class Introduce    {        public string Name { get; set; }        public string Class { get; set; }        public string Number { get; set; }    }    public class Region    {        public string Province { get; set; }        public string City { get; set; }        public string Area { get; set; }    }    public class Detailed_address    {        public string Address { get; set; }    }}

在Startup中添加如下代码

            #region 服务注册,在控制器中通过注入的形式使用            services.AddOptions();            services.Configure<Information>(Configuration.GetSection("Information"));            #endregion

控制器中使用：

{  "Connection": {    "dbContent": "Data Source=.;Initial Catalog=test;User ID=sa;Password=123456"  },  //------------------------  "Content": [    {      "Trade_name": {        "test1": "小熊饼干",        "test2": "旺仔QQ糖",        "test3": "娃哈哈牛奶"      }    }  ],  //------------------------  "Logging": {    "LogLevel": {      "Default": "Information",      "Microsoft": "Warning",      "Microsoft.Hosting.Lifetime": "Information"    }  },  "AllowedHosts": "*",  //==============================  "Information": {    "school": {      "Introduce": {        "Name": "实验小学",        "Class": "中班",        "Number": "15人"      },      "Region": {        "Province": "湖北",        "City": "武汉",        "Area": "洪山区"      },      "Detailed_address": [        {          "Address": "佳园路207号"        }      ]    }  }  //==============================}

第三种：这种应该比较常见,任意读取自定义的json文件

首先建立一个json文件

{  "system_version": {    "Edition": ".Net Core 3.0",    "Project_Name": "Read.json"  }}

再建一个类,封装一个方法

using Microsoft.Extensions.Configuration;using System;using System.Collections.Generic;using System.Linq;using System.Threading.Tasks;namespace Read.json{    public class Json_File    {        public IConfigurationRoot Read_Json_File()        {            //这句代码会读取read_json.json中的内容            return new ConfigurationBuilder().AddJsonFile("read_json.json")                                             .Build();        }    }}

在控制器中调用：

[HttpGet]        public async Task<IActionResult> ReadSystemVersion()        {            var configuration = _json_File.Read_Json_File();            string system = "使用的是" + configuration["system_version:Edition"] + "的版本" + "," +                            "项目名称是" + configuration["system_version:Project_Name"];            return Json(new            {                data = system            });        }

本文来自 C#.Net教程栏目，欢迎学习！

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