NetCore Dapper封装

一、前期环境准备

1、创建一个core webapi的项目，基于core3.1版本创建一个项目。

2、Dapper安装，使用NuGet来安装Dapper程序包

　　Install-Package Dapper -Version 2.0.30

　　Install-Package Dapper.Contrib -Version 2.0.30

3、MySQL.Data的程序包（可以使用其他数据库，如：sqlserver,sqllite等）

　　Install-Package Dapper -Version 8.0.25

4、appsettings.json文件中添加链接数据库的字符串（其他数据库连接字符串，自行更改）：

"ConnectionStrings": {
　　"DefaultConnection": "server=服务器;port=端口号;database=regatta{0};SslMode=None;uid=userName;pwd=passWord;Allow User Variables=true"
}

二、封装

1、IDapperContext：

/// <summary>
/// Dapper上下文
/// </summary>
public interface IDapperContext : IDisposable
{
/// <summary>
/// 数据库连接对象
/// </summary>
IDbConnection ReadConnection { get; }

/// <summary>
/// 数据库连接对象
/// </summary>
IDbConnection WriteConnection { get; }
}

2、DapperContext：

public class DapperContext : IDapperContext
    {
        /// <summary>
        /// 读连接字符串
        /// </summary>
        private string _readConnectionString;

        /// <summary>
        /// 写连接字符串
        /// </summary>
        private string _writeConnectionString;

        private bool _useMiniProfiling;

        /// <summary>
        /// 读连接
        /// </summary>
        private IDbConnection _readConnection;

        /// <summary>
        /// 写连接
        /// </summary>
        private IDbConnection _wrteConnection;

        /// <summary>
        /// 配置
        /// </summary>
        private readonly AppSetting _appSetting;

        /// <summary>
        /// 构造函数注入IOptions
        /// </summary>
        /// <param name="appSetting"></param>
        public DapperContext(IOptions<AppSetting> appSetting)
        {
            _appSetting = appSetting.Value;
            _readConnectionString = _appSetting.ReadOnlyConnectionString;
            _writeConnectionString = _appSetting.SetConnectionString;
            _useMiniProfiling = _appSetting.UseMiniProfiling;
        }

        /// <summary>
        /// 连接字符串
        /// </summary>
        /// <param name="connectionString">读写连接字符串</param>
        public DapperContext(string connectionString)
        {
            _readConnectionString = connectionString;
            _writeConnectionString = connectionString;
        }

        #region 读

        /// <summary>
        /// 获取连接
        /// </summary>
        public IDbConnection ReadConnection
        {
            get
            {
                if (_readConnection == null || _readConnection.State == ConnectionState.Closed)
                {
                    if (_useMiniProfiling)
                    {
                        _readConnection = new ProfiledDbConnection(new MySqlConnection(_readConnectionString), MiniProfiler.Current);
                    }
                    else
                    {
                        _readConnection = new MySqlConnection(_readConnectionString);
                    }
                }
                if (_readConnection.State != ConnectionState.Open)
                {
                    _readConnection.Open();
                }
                return _readConnection;
            }
        }

        /// <summary>
        /// 释放连接
        /// </summary>
        public void Dispose()
        {
            if (_readConnection != null && _readConnection.State == ConnectionState.Open)
                _readConnection.Close();
            if (_wrteConnection != null && _wrteConnection.State == ConnectionState.Open)
                _wrteConnection.Close();
        }

        #endregion 

        #region 写

        /// <summary>
        /// 获取连接
        /// </summary>
        public IDbConnection WriteConnection
        {
            get
            {
                if (_wrteConnection == null || _wrteConnection.State == ConnectionState.Closed)
                {
                    if (_useMiniProfiling)
                    {
                        _wrteConnection = new ProfiledDbConnection(new MySqlConnection(_writeConnectionString), MiniProfiler.Current);
                    }
                    else
                    {
                        _wrteConnection = new MySqlConnection(_writeConnectionString);
                    }
                }
                if (_wrteConnection.State != ConnectionState.Open)
                {
                    _wrteConnection.Open();
                }
                return _wrteConnection;
            }
        }

        #endregion
    }

3、IRepository（仓储）：

 /// <summary>
    /// 数据库CRUD等操作
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public interface IRepository<T> where T : class
    {
        /// <summary>
        /// 上下文
        /// </summary>
        IDapperContext Context { get; }

        /// <summary>
        /// 只读连接
        /// </summary>
        IDbConnection ReadConnection { get; }

        /// <summary>
        /// 读写连接
        /// </summary>
        IDbConnection WriteConnection { get; }

        /// <summary>
        /// 获取分页数据
        /// </summary>
        /// <typeparam name="TEntity"></typeparam>
        /// <param name="criteria">查询设置</param>
        /// <param name="param"></param>
        /// <returns></returns>
        PageDataView<TEntity> GetPageData<TEntity>(PageCriteria criteria, object param = null) where TEntity : class;

        /// <summary>
        ///
        /// </summary>
        /// <typeparam name="TEntity"></typeparam>
        /// <param name="criteria"></param>
        /// <param name="param"></param>
        /// <returns></returns>
        PageDataView<TEntity> GetAllData<TEntity>(PageCriteria criteria, object param = null) where TEntity : class;

        /// <summary>
        /// 添加数据
        /// </summary>
        /// <param name="entity"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        long Add(T entity, IDbTransaction transaction = null, int? commandTimeout = null);

        /// <summary>
        /// 批量添加数据
        /// </summary>
        /// <param name="entity"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        long BatchAdd(IEnumerable<T> list, IDbTransaction transaction = null, int? commandTimeout = null);

        /// <summary>
        ///
        /// </summary>
        /// <param name="entity"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        bool Update(T entity, IDbTransaction transaction = null, int? commandTimeout = null);

        /// <summary>
        /// 删除单条数据
        /// </summary>
        /// <param name="entity"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        bool Remove(T entity, IDbTransaction transaction = null, int? commandTimeout = null);

        /// <summary>
        /// 批量删除
        /// </summary>
        /// <param name="list"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        bool BatchRemove(IEnumerable<T> list, IDbTransaction transaction = null, int? commandTimeout = null);

        /// <summary>
        /// 根据主键获取数据
        /// </summary>
        /// <param name="key"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        T GetByKey(object key, IDbTransaction transaction = null, int? commandTimeout = null);

        /// <summary>
        /// 获取所有数据
        /// </summary>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        IEnumerable<T> GetAll(IDbTransaction transaction = null, int? commandTimeout = null);

        /// <summary>
        /// 根据条件获取数据列表
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="param"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        IEnumerable<T> GetBy(object sql = null, object param = null, IDbTransaction transaction = null, int? commandTimeout = null);

        /// <summary>
        /// 查询数据列表
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        IEnumerable<dynamic> Query(string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null);

        /// <summary>
        /// 多对象查询
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="param"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <param name="commandType"></param>
        /// <returns></returns>
        GridReader QueryMultiple(string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null);

        /// <summary>
        /// 执行sql
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        int Excute(string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null);

        /// <summary>
        /// 执行是否存在数据
        /// </summary>
        /// <param name="sqlStr">查询（例：SELECT COUNT(1)  FROM XXX ）</param>
        /// <returns></returns>
        bool Exists(string sqlStr, object param = null);
    }

4、Repository（仓储实现）：

public class Repository<T> : IRepository<T> where T : class
    {
        public Repository(IDapperContext context)
        {
            Context = context;
        }

        public IDapperContext Context { get; private set; }
        public IDbConnection ReadConnection => Context.ReadConnection;

        public IDbConnection WriteConnection => Context.WriteConnection;

        public PageDataView<TEntity> GetPageData<TEntity>(PageCriteria criteria, object param = null) where TEntity : class
        {
            var p = new DynamicParameters();
            string proName = "ProcGetPageData";
            p.Add("_tables", criteria.TableName);
            p.Add("_fields", criteria.Fields);
            p.Add("_where", criteria.Condition);
            p.Add("_pageIndex", criteria.CurrentPage);
            p.Add("_pageSize", criteria.PageSize);
            p.Add("_orderby", criteria.Sort);
            p.Add("_totalcount", dbType: DbType.Int32, direction: ParameterDirection.Output);
            p.Add("_pagecount", dbType: DbType.Int32, direction: ParameterDirection.Output);
            var pageData = new PageDataView<TEntity>();

            pageData.Items = ReadConnection.Query<TEntity>(proName, p, commandType: CommandType.StoredProcedure, commandTimeout: 300).ToList();
            pageData.TotalNum = p.Get<int>("_totalcount");
            pageData.TotalPageCount = p.Get<int>("_pagecount"); //Convert.ToInt32(Math.Ceiling(pageData.TotalNum * 1.0 / criteria.PageSize));
            pageData.CurrentPage = criteria.CurrentPage > pageData.TotalPageCount ? pageData.TotalPageCount : criteria.CurrentPage;

            return pageData;
        }

        public PageDataView<TEntity> GetAllData<TEntity>(PageCriteria criteria, object param = null) where TEntity : class
        {
            var p = new DynamicParameters();
            string proName = "ProcGetAllData";
            p.Add("_tables", criteria.TableName);
            p.Add("_fields", criteria.Fields);
            p.Add("_where", criteria.Condition);
            p.Add("_orderby", criteria.Sort);
            p.Add("_totalcount", dbType: DbType.Int32, direction: ParameterDirection.Output);
            var pageData = new PageDataView<TEntity>();
            pageData.Items = ReadConnection.Query<TEntity>(proName, p, commandType: CommandType.StoredProcedure, commandTimeout: 300).ToList();
            pageData.TotalNum = p.Get<int>("_totalcount");
            return pageData;
        }

        public long Add(T entity, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            if (entity == null)
            {
                throw new ArgumentNullException("entity", "Add to DB null entity");
            }
            var res = WriteConnection.Insert(entity, transaction: transaction, commandTimeout: commandTimeout);
            return res;
        }

        public long BatchAdd(IEnumerable<T> list, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            if (list == null)
            {
                throw new ArgumentNullException("list", "BatchAdd to DB null entity");
            }
            var res = WriteConnection.Insert(list, transaction: transaction, commandTimeout: commandTimeout);
            return res;
        }

        public virtual bool Update(T entity, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            if (entity == null)
            {
                throw new ArgumentNullException("entity", "Update in DB null entity");
            }
            return WriteConnection.Update(entity, transaction: transaction, commandTimeout: commandTimeout);
        }

        public virtual bool Remove(T entity, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            if (entity == null)
            {
                throw new ArgumentNullException("entity", "Remove in DB null entity");
            }
            return WriteConnection.Delete(entity, transaction: transaction, commandTimeout: commandTimeout);
        }

        public bool BatchRemove(IEnumerable<T> list, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            if (list == null)
            {
                throw new ArgumentNullException("list", "BatchAdd to DB null entity");
            }
            return WriteConnection.Delete(list, transaction: transaction, commandTimeout: commandTimeout);
        }

        public virtual T GetByKey(object queryId, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            if (queryId == null)
            {
                throw new ArgumentNullException("queryId");
            }
            return ReadConnection.Get<T>(queryId, transaction: transaction, commandTimeout: commandTimeout);
        }

        public virtual IEnumerable<T> GetAll(IDbTransaction transaction = null, int? commandTimeout = null)
        {
            return ReadConnection.GetAll<T>(transaction: transaction, commandTimeout: commandTimeout);
        }

        public virtual IEnumerable<T> GetBy(object sql = null, object param = null, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            return ReadConnection.Query<T>(sql.ToString(), param, commandTimeout: commandTimeout);
        }

        public IEnumerable<dynamic> Query(string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            return ReadConnection.Query<dynamic>(sql, param);
        }

        public GridReader QueryMultiple(string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null, CommandType? commandType = null)
        {
            return ReadConnection.QueryMultiple(sql, param, transaction, commandTimeout, commandType);
        }

        public int Excute(string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            return WriteConnection.Execute(sql, param, transaction: transaction);
        }

        public bool Exists(string sqlStr, object param = null)
        {
            return ReadConnection.Query<dynamic>(sqlStr, param).Count() > 0 ? true : false;
        }
    }

利用工厂模式创建仓库

5、IFactoryRepository：

    /// <summary>
    /// 创建仓库接口
    /// </summary>
    public interface IFactoryRepository
    {
        /// <summary>
        /// 创建仓库
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="context"></param>
        /// <returns></returns>
        IRepository<T> CreateRepository<T>(IDapperContext context) where T : class;
    }

     /// <summary>
    /// 工厂
    /// </summary>
    public class FactoryRepository : IFactoryRepository
    {
        /// <summary>
        /// 创建Repository
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="context"></param>
        /// <returns></returns>
        public IRepository<T> CreateRepository<T>(IDapperContext context) where T : class
        {
            IRepository<T> repository = new Repository<T>(context);
            return repository;
        }
    }