.Net Core读取Json配置文件的实现示例

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
   });
  }

demo地址：https://github.com/davenever/read_json.git

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。