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"
  }
  ]
 }
 }
 //==============================
}