前言：在與傳統的asp.net MVC項目相比,.net core項目在項目目錄的文件結構上和功能上與前者都有很大的區別。例如：在.net core中使用Startup.cs取代Global.asax文件用于加載應用程序的配置和各種啟動項。appsettings.json取代web.config文件用于存儲應用程序所需的配置參數等等。。。

OK！步入正題,下面來說一下如何讀取Json配置文件中的參數。

第一種:使用IConfiguration接口

我們先在appsettings.json中配置好數據庫連接字符串,然后讀取它

{ "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()  {   //讀參   string conn = _configuration["Connection:dbContent"];   return "";  } }}

當然也可以讀取數組形式的json,一樣的先在appsettings.json中寫好配置參數，如下：

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

比如我們想讀取test1

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

第二種：使用IOptions<T>來讀取json配置文件

先把NuGet包導進項目：Microsoft.Extensions.Options.ConfigurationExtensions

首先在appsettings.json中添加節點如下

{ "Connection": { "dbContent": "Data Source=.;Initial Catalog=test;User ID=sa;Password=123456" }, //------------------------ "Content": [ {  "Trade_name": {  "test1": "小熊餅干",  "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": "實驗小學",  "Class": "中班",  "Number": "15人"  },  "Region": {  "Province": "湖北",  "City": "武漢",  "Area": "洪山區"  },  "Detailed_address": [  {   "Address": "佳園路207號"  }  ] } } //==============================}