.Net Core读取Json配置文件的实现示例

2020-01-17 20:30:12

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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：

using System;using System.Collections.Generic;using System.Linq;using System.Threading.Tasks;using Microsoft.AspNetCore.Mvc;using Microsoft.Extensions.Configuration;using Microsoft.Extensions.Options;namespace Read.json.Controllers{ [Route("api/[controller]/[action]")] [ApiController] public class ReadController : Controller {  private IConfiguration _configuration;  readonly Information _Information;  readonly IOptions<Information> _options;  public ReadController(IConfiguration configuration,        Information Information,        IOptions<Information> options)  {   _configuration = configuration;   _Information = Information;   _options = options;  }  [HttpGet]  public async Task<IActionResult> ReadInformation()  {   string Address = _options.Value.school.Region.Province + "-" +        _options.Value.school.Region.City + "-" +        _options.Value.school.Region.Area + "-" +        _options.Value.school.Detailed_address[0].Address + "-" +        _options.Value.school.Introduce.Name + "-" +        _options.Value.school.Introduce.Class + "-" +        _options.Value.school.Introduce.Number;   return Json(Address);  }  [HttpPost]  public async Task<string> ReadJson()  {   string conn = _configuration["Connection:dbContent"];   string commodity = _configuration["Content:0:Trade_name:test1"];   return "";  } }}

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   });  }