我要评论在.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代码网。
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