.Net Core如何读取Json配置文件

互联网 19-11-27

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             });         }