在.Net Framework中，配置文件一般采用的是XML格式的，.NET Framework提供了专门的ConfigurationManager来读取配置文件的内容，.net core中推荐使用json格式的配置文件，那么在.net core中该如何读取json文件呢？
一、在Startup类中读取json配置文件
1、使用Configuration直接读取
看下面的代码：
public IConfiguration Configuration { get; }
Configuration属性就是.net core中提供的用来读取json文件。例如：
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
string option1 = $"option1 = {this.Configuration["Option1"]}";
string option2 = $"option2 = {this.Configuration["Option2"]}";
string suboption1 = $"suboption1 = {this.Configuration["subsection:suboption1"]}";
// 读取数组
string name1 = $"Name={this.Configuration["student:0:Name"]} ";
string age1 = $"Age= {this.Configuration["student:0:Age"]}";
string name2 = $"Name={this.Configuration["student:1:Name"]}";
string age2 = $"Age= {this.Configuration["student:1:Age"]}";
// 输出
app.Run(c => c.Response.WriteAsync(option1+"\r\n"+option2+ "\r\n"+suboption1+ "\r\n"+name1+ "\r\n"+age1+ "\r\n"+name2+ "\r\n"+age2));
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
else
{
app.UseHsts();
}
app.UseHttpsRedirection();
app.UseMvc();
}
结果：
2、使用IOptions接口
1、定义实体类
public class MongodbHostOptions
{
/// <summary>
/// 连接字符串
/// </summary>
public string Connection { get; set; }
/// <summary>
/// 库
/// </summary>
public string DataBase { get; set; }
public string Table { get; set; }
}
2、修改json文件
在appsettings.json文件中添加MongodbHost节点：
{
"Logging": {
"LogLevel": {
"Default": "Warning"
}
},
"option1": "value1_from_json",
"option2": 2,
"subsection": {
"suboption1": "subvalue1_from_json"
},
"student": [
{
"Name": "Gandalf",
"Age": "1000"
},
{
"Name": "Harry",
"Age": "17"
}
],
"AllowedHosts": "*",
//MongoDb
"MongodbHost": {
"Connection": "mongodb://127.0.0.1:27017",
"DataBase": "TemplateDb",
"Table": "CDATemplateInfo"
}
}
注意：
MongodbHost里面的属性名必须要和定义的实体类里面的属性名称一致。
3、在StartUp类里面配置
添加OptionConfigure方法绑定
private void OptionConfigure(IServiceCollection services)
{
//MongodbHost信息
services.Configure<MongodbHostOptions>(Configuration.GetSection("MongodbHost"));
}
在ConfigureServices方法中调用上面定义的方法：
public void ConfigureServices(IServiceCollection services)
{
// 调用OptionConfigure方法
OptionConfigure(services);
services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
}
在控制器中使用，代码如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Options;
namespace ReadJsonDemo.Controllers
{
[Route("api/[controller]")]
[ApiController]
public class MongodbController : ControllerBase
{
private readonly MongodbHostOptions _mongodbHostOptions;
/// <summary>
/// 通过构造函数注入
/// </summary>
/// <param name="mongodbHostOptions"></param>
public MongodbController(IOptions<MongodbHostOptions> mongodbHostOptions)
{
_mongodbHostOptions = mongodbHostOptions.Value;
}
[HttpGet]
public async Task Get()
{
await Response.WriteAsync("Connection:" + _mongodbHostOptions.Connection + "\r\nDataBase;" + _mongodbHostOptions.DataBase + "\r\nTable:" + _mongodbHostOptions.Table);
}
}
}
运行结果：
3、读取自定义json文件
在上面的例子中都是读取的系统自带的appsettings.json文件，那么该如何读取我们自己定义的json文件呢？这里可以使用ConfigurationBuilder类。
实例化类
var builder = new ConfigurationBuilder();
添加方式1
builder.AddJsonFile("path", false, true);
其中path表示json文件的路径，包括路径和文件名。
添加方式2
builder.Add(new JsonConfigurationSource {Path= "custom.json",Optional=false,ReloadOnChange=true }).Build()
具体代码如下：
private void CustomOptionConfigure(IServiceCollection services)
{
IConfiguration _configuration;
var builder = new ConfigurationBuilder();
// 方式1
//_configuration = builder.AddJsonFile("custom.json", false, true).Build();
// 方式2
_configuration = builder.Add(new JsonConfigurationSource {Path= "custom.json",Optional=false,ReloadOnChange=true }).Build();
services.Configure<WebSiteOptions>(_configuration.GetSection("WebSiteConfig"));
}
ConfigureServices方法如下：
public void ConfigureServices(IServiceCollection services)
{
// 调用OptionConfigure方法
OptionConfigure(services);
CustomOptionConfigure(services);
services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
}
控制器代码如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Options;
namespace ReadJsonDemo.Controllers
{
[Route("api/[controller]")]
[ApiController]
public class MongodbController : ControllerBase
{
private readonly MongodbHostOptions _mongodbHostOptions;
private readonly WebSiteOptions _webSiteOptions;
/// <summary>
/// 通过构造函数注入
/// </summary>
/// <param name="mongodbHostOptions"></param>
public MongodbController(IOptions<MongodbHostOptions> mongodbHostOptions,IOptions<WebSiteOptions> webSiteOptions)
{
_mongodbHostOptions = mongodbHostOptions.Value;
_webSiteOptions = webSiteOptions.Value;
}
[HttpGet]
public async Task Get()
{
await Response.WriteAsync("Connection:" + _mongodbHostOptions.Connection + "\r\nDataBase;" + _mongodbHostOptions.DataBase + "\r\nTable:" + _mongodbHostOptions.Table);
await Response.WriteAsync("\r\n");
await Response.WriteAsync("WebSiteName:" + _webSiteOptions.WebSiteName + "\r\nWebSiteUrl;" + _webSiteOptions.WebSiteUrl);
}
}
}
二、在类库中读取json文件
在上面的示例中都是直接在应用程序中读取的，那么如何在单独的类库中读取json文件呢？看下面的示例代码：
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
namespace Common
{
public class JsonConfigHelper
{
public static T GetAppSettings<T>(string fileName, string key) where T : class, new()
{
// 获取bin目录路径
var directory = AppContext.BaseDirectory;
directory = directory.Replace("\\", "/");
var filePath = $"{directory}/{fileName}";
if (!File.Exists(filePath))
{
var length = directory.IndexOf("/bin");
filePath = $"{directory.Substring(0, length)}/{fileName}";
}
IConfiguration configuration;
var builder = new ConfigurationBuilder();
builder.AddJsonFile(filePath, false, true);
configuration = builder.Build();
var appconfig = new ServiceCollection()
.AddOptions()
.Configure<T>(configuration.GetSection(key))
.BuildServiceProvider()
.GetService<IOptions<T>>()
.Value;
return appconfig;
}
}
}
注意：这里要添加如下几个程序集，并且要注意添加的程序集的版本要和.net core web项目里面的程序集版本一致，否则会报版本冲突的错误
- 1、Microsoft.Extensions.Configuration
- 2、Microsoft.Extensions.configuration.json
- 3、Microsoft.Extensions.Options
- 4、Microsoft.Extensions.Options.ConfigurationExtensions
- 5、Microsoft.Extensions.Options
json文件如下：
{
"WebSiteConfig": {
"WebSiteName": "CustomWebSite",
"WebSiteUrl": "https:localhost:12345"
},
"DbConfig": {
"DataSource": "127.0.0.1",
"InitialCatalog": "MyDb",
"UserId": "sa",
"Password": "123456"
}
}
DbHostOptions实体类定义如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
namespace ReadJsonDemo
{
public class DbHostOptions
{
public string DataSource { get; set; }
public string InitialCatalog { get; set; }
public string UserId { get; set; }
public string Password { get; set; }
}
}
注意：这里的DbHostOptions实体类应该建在单独的类库中，这里为了演示方便直接建在应用程序中了。
在控制器中调用：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Common;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Options;
namespace ReadJsonDemo.Controllers
{
[Route("api/[controller]")]
[ApiController]
public class MongodbController : ControllerBase
{
private readonly MongodbHostOptions _mongodbHostOptions;
private readonly WebSiteOptions _webSiteOptions;
/// <summary>
/// 通过构造函数注入
/// </summary>
/// <param name="mongodbHostOptions"></param>
public MongodbController(IOptions<MongodbHostOptions> mongodbHostOptions,IOptions<WebSiteOptions> webSiteOptions)
{
_mongodbHostOptions = mongodbHostOptions.Value;
_webSiteOptions = webSiteOptions.Value;
}
[HttpGet]
public async Task Get()
{
DbHostOptions dbOptions = JsonConfigHelper.GetAppSettings<DbHostOptions>("custom.json", "DbConfig");
await Response.WriteAsync("DataSource:" + dbOptions.DataSource + "\r\nInitialCatalog;" + dbOptions.InitialCatalog+ "\r\nUserId:"+dbOptions.UserId+ "\r\nPassword"+dbOptions.Password);
await Response.WriteAsync("\r\n");
await Response.WriteAsync("Connection:" + _mongodbHostOptions.Connection + "\r\nDataBase;" + _mongodbHostOptions.DataBase + "\r\nTable:" + _mongodbHostOptions.Table);
await Response.WriteAsync("\r\n");
await Response.WriteAsync("WebSiteName:" + _webSiteOptions.WebSiteName + "\r\nWebSiteUrl;" + _webSiteOptions.WebSiteUrl);
}
}
}
运行结果：
到此这篇关于ASP.NET CORE读取json格式配置文件的文章就介绍到这了。希望对大家的学习有所帮助，也希望大家多多支持猪先飞。
原文出处：https://www.cnblogs.com/dotnet261010/p/10172961.html