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:
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