系列目录
本系列涉及到的源码下载地址：https://github.com/seabluescn/Blog_WebApi
一、本篇概述
本篇描述appsettings.json的使用，包括：
1、配置的基本读取
2、读取配置信息到自定义的对象
3、自定义配置文件
一、配置的基本读取
要读取的配置文件内容如下：
{
"ConnString": "MySQL Connect String",
"Logging": {
"IncludeScopes": false,
"Debug": {
"LogLevel": {
"Default": "Warning"
}
},
"Console": {
"LogLevel": {
"Default": "Warning"
}
}
},
"SystemConfig": {
"UploadFile": "d:\\files",
"AnnexUrl": "http://192.168.0.177:81/",
"Admin": {
"Name": "admin",
"Age": "",
"Allow": "True"
},
"DefaultPassword": ""
}
}
读取配置文件的方法如下：
public class Startup
{
public Startup(IConfiguration configuration,IHostingEnvironment env)
{
Configuration = configuration;
_env = env;
} public IConfiguration Configuration { get; }
public IHostingEnvironment _env { get; } // This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc(); var ConnString = Configuration["ConnString"];
var UploadFile = Configuration.GetSection("SystemConfig")["UploadFile"];
var AdminName = Configuration.GetSection("SystemConfig").GetSection("Admin")["Name"];
}
}
还有一种读法：
ConnString = Configuration["ConnString"];
UploadFile = Configuration["SystemConfig:UploadFile"];
AdminName = Configuration["SystemConfig:Admin:Name"];
这里Startup类在构造时已经帮我们注入了Configuration，如果要在自己的Controller内使用，需要自己注入。
public class ValuesController : Controller
{
private IConfiguration _configuration; public ValuesController(IConfiguration configuration)
{
_configuration = configuration;
} [HttpGet]
public IEnumerable<string> Get()
{
var ConnString = _configuration["ConnString"];
return new string[] { "value1", "value2" };
}
}
二、读取配置信息到自定义的对象
新建一个类，用来存储配置信息，类的结构应和配置文件一致。
public class SystemConfig
{
public String UploadFile { get; set; }
public String AnnexUrl { get; set; }
public User Admin { get; set; }
public String DefaultPassword { get; set; }
} public class User
{
public String Name { get; set; }
public int Age { get; set; }
public bool Allow { get; set; }
}
在startup类的ConfigureServices方法内，提供如下代码：
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
} public IConfiguration Configuration { get; } public void ConfigureServices(IServiceCollection services)
{
services.AddMvc(); services.AddOptions();
services.Configure<SystemConfig>(Configuration.GetSection("SystemConfig"));
}
}
}
然后在Controller中进行注入并使用。
public class ValuesController : Controller
{
private IOptions<SystemConfig> _setting; public ValuesController( IOptions<SystemConfig> setting)
{
_setting = setting;
} [HttpGet("setting")]
public IEnumerable<string> GetSetting()
{
var UploadFile = _setting.Value.UploadFile;
var AdminName = _setting.Value.Admin.Name;
var AdminAge = _setting.Value.Admin.Age;
var AdminAllow = _setting.Value.Admin.Allow; return new string[] { "value1", "value2" };
}
}
可以看到，这样在业务方法内通过 _setting 来都取配置信息就非常方便了。
三、自定义配置文件
以上操作的是系统默认的配置文件appsettings.json。如果我们需要增加自己的配置文件该如何处理？
新建一个配置文件：mysetting.json
{
"ConnString": "MySQL Connect String",
"SystemConfig": {
"UploadFile": "d:\\myfiles",
"AnnexUrl": "http://192.168.0.177:81/my",
"Admin": {
"Name": "myadmin",
"Age": "",
"Allow": "False"
},
"DefaultPassword": ""
}
}
在Startup类的ConfigureServices方法输入以下代码：
public class Startup
{
public Startup(IConfiguration configuration,IHostingEnvironment env)
{
Configuration = configuration;
_env = env;
} public IConfiguration Configuration { get; }
public IHostingEnvironment _env { get; } public void ConfigureServices(IServiceCollection services)
{
services.AddMvc(); var rootpath = _env.ContentRootPath;
var builder = new ConfigurationBuilder()
.SetBasePath(_env.ContentRootPath)
.AddJsonFile("mysetting.json",optional: true, reloadOnChange: true)
.AddEnvironmentVariables();
var MyConfiguration = builder.Build(); services.AddOptions();
services.Configure<SystemConfig>(MyConfiguration.GetSection("SystemConfig"));
}
}
用自己创建的Configuration进行服务的注册，创建过程中需要用到IHostingEnvironment，这个对象在Startup类构建时进行注入。
剩下的用法和默认配置用法就一样了。