SqlSugar学习笔记三——配置支持动态分库查询

描述：当程序在在运行时，如何能动态的进行拓展，在不停止程序运行的情况下，通过添加数据库链接到配置文件，实现查询级别的负载均衡？接下来通过一个简单的配置

一、读取配置文件类

 public class ConnectionConfigManager
    {
        private static ConnectionConfig _SqlSugarConnectionConfig = null;
         
        static ConnectionConfigManager()
        {
            InitSqlSugarConnectionfonfig();
        }

        public static ConnectionConfig GetConnectionConfigInstance()
        {
            return _SqlSugarConnectionConfig;
        }


        /// <summary>
        /// 重新读取配置文件里的信息
        /// 1.可以监听配置文件，当文件内容改变时进行调用
        /// 2.通过手动调用重新加载配置文件
        /// </summary>
        public void RefreshData()
        {
            ConnectionConfigManager.InitSqlSugarConnectionfonfig();
            ConnectionConfig connection = ConnectionConfigManager.GetConnectionConfigInstance();
        }

        /// <summary>
        /// 这个方法就是初始化_SqlSugarConnectionConfig 字段中的内容
        /// </summary>
        public static void InitSqlSugarConnectionfonfig()
        {
            var builder = new ConfigurationBuilder().AddJsonFile("appsettings.json");
            IConfigurationRoot configuration = builder.Build();


            CustomConnectionConfig customConnectionConfig = new CustomConnectionConfig();
            configuration.Bind("ConnectionConfig", customConnectionConfig);


            ConnectionConfig connection = new ConnectionConfig()
            {
                DbType = DbType.SqlServer,
                InitKeyType = InitKeyType.Attribute,
                IsAutoCloseConnection = true
            };

            connection.ConnectionString = customConnectionConfig.ConnectionString;

            List<SlaveConnectionConfig> slaveConnectionList = new List<SlaveConnectionConfig>();
            foreach (var SlaveConnection in customConnectionConfig.SlaveConnectionConfigs!)
            {
                slaveConnectionList.Add(new SlaveConnectionConfig()
                {
                    ConnectionString = SlaveConnection.ConnectionString,
                    HitRate = 10
                });
            }
            connection.SlaveConnectionConfigs = slaveConnectionList;

            _SqlSugarConnectionConfig = connection;
        }

    }

    public class CustomConnectionConfig
    {
        /// <summary>
        /// 主库链接
        /// </summary>
        public string? ConnectionString { get; set; }

        /// <summary>
        /// 从库链接
        /// </summary>
        public List<CustomSlaveConnectionConfig>? SlaveConnectionConfigs { get; set; }

    }
    public class CustomSlaveConnectionConfig
    {
        public string? ConnectionString
        {
            get;
            set;
        }
    }

二、读取配置文件

ConnectionConfig connectionConfig = ConnectionConfigManager.GetConnectionConfigInstance(); 

三、重新加载配置文件

ConnectionConfigManager.RefreshData();