輕量型ORM框架Dapper的使用

在真實的項目開發中，可能有些人比較喜歡寫SQL語句，但是對於EF這種ORM框架比較排斥，那么輕量型的Dapper就是一個不錯的選擇，即讓你寫sql語句了，有進行了關系對象映射。其實對於EF吧，我說下我個人的見解，EF是相對來說比較重的ORM框架，它是講究通用性的框架，而非單純的實現某種需求的框架，不得不否認的說，EF的開發效率要比用單純的ADO.NET寫sql語句的效率高的不是一點半點，可能很多人會說EF的性能低等等，針對這種問題有時候是需要折中的來講，從另一個方面來講，你用了ADO.NET寫sql語句是性能好了，但是你得到的是弱類型的DataTable或者DataSet，常規在MVC的開發中，其實你難道不轉換成集合或者單個對象嗎？總不會拿着DataTable用吧，當你把弱類型的Datatable轉換成List<T>的時候，一般來講分兩種轉換，一種是利用反射，這其實也就成了關系對象映射了，跟ORM框架沒什么區別了，第二種無非是循環賦值了，但是這種的開箱裝箱的損耗也是很大的，最終你得到你想要的數據類型的時候其實折中算下來相比較EF直接得到，中間你又走了很多的彎路了，我在開發中一般EF打頭陣，輕量的Dapper做輔助，因為有時候開發效率很重要，性能的問題我不會過多在SQL優化上下功夫，我一般會在中間緩存上做處理。下面是我簡單的對Dapper的小包裝，代碼如下：

 

public class LiunianContext:IDisposable { private static readonly string _dbConnectionStr = ConfigurationManager.ConnectionStrings["XXXContext"].ConnectionString; private IDbConnection dbConnection; private IDbConnection DbConnection { get { if (_dbConnectionStr.IsNotNullOrEmpty()) dbConnection = new SqlConnection(_dbConnectionStr); else throw new ArgumentNullException("dbConnectionStr"); bool isClosed = dbConnection.State == ConnectionState.Closed; if (isClosed) dbConnection.Open(); return dbConnection; } } /// <summary> /// 執行增刪改操作(包括批量操作) /// </summary> /// <param name="sql">sql語句(有參數參數化)</param> /// <param name="param">參數化值</param> /// <returns></returns> public bool Execute(string sql, object param) { bool isSuccess = false; if (sql.IsNotNullOrEmpty()) { try { int result = DbConnection.Execute(sql, param); isSuccess = result > 0 ? true : false; } catch { isSuccess = false; } } return isSuccess; } /// <summary> /// 執行存儲過程操作 /// </summary> /// <param name="sql">存儲過程名稱</param> /// <param name="param">參數化值</param> /// <returns>返回存儲過程是否執行成功</returns> public bool ExecuteStored(string storedName, object param) { bool isSuccess = false; if (storedName.IsNotNullOrEmpty()) { try { int result = DbConnection.Execute(storedName, param, commandType: CommandType.StoredProcedure); isSuccess = result > 0 ? true : false; } catch { isSuccess = false; } } return isSuccess; } /// <summary> /// 執行存儲過程操作 /// </summary> /// <param name="storedName">存儲過程名稱</param> /// <param name="param">存儲過程參數</param> /// <returns>返回存儲過程要返回的值</returns> public DynamicParameters ExecuteStored(string storedName, DynamicParameters param) { if (storedName.IsNotNullOrEmpty()) { try { DbConnection.Execute(storedName, param, commandType: CommandType.StoredProcedure); } catch { } } return param; } /// <summary> /// 查詢操作 /// </summary> /// <typeparam name="T">返回集合的類型</typeparam> /// <param name="sql">sql語句</param> /// <param name="param">參數化值</param> /// <returns></returns> public IEnumerable<T> Query<T>(string sql, object param) { IEnumerable<T> _list = default(IEnumerable<T>); if (!string.IsNullOrEmpty(sql)) { try { _list = DbConnection.Query<T>(sql, param); } catch { } } return _list; } /// <summary> /// 執行存儲過程查詢操作 /// </summary> /// <typeparam name="T">返回集合的類型</typeparam> /// <param name="storedName">存儲過程</param> /// <param name="param">參數化值</param> /// <returns></returns> public IEnumerable<T> QueryStored<T>(string storedName, object param) { IEnumerable<T> _list = default(IEnumerable<T>); if (!string.IsNullOrEmpty(storedName)) { try { _list = DbConnection.Query<T>(storedName,commandType: CommandType.StoredProcedure); } catch { } } return _list; } /// <summary> /// 查詢操作返回默認第一條數據(如返回null則創建默認類型) /// </summary> /// <typeparam name="T"></typeparam> /// <param name="sql"></param> /// <param name="param"></param> /// <returns></returns> public T FirstOrDefault<T>(string sql, object param) { var model = default(T); if (!string.IsNullOrEmpty(sql)) { try { model = DbConnection.Query<T>(sql, param).FirstOrDefault(); } catch { } } return model == null ? Activator.CreateInstance<T>() : model; } /// <summary> /// 查詢一組SQL語句並返回值 /// </summary> /// <typeparam name="T1">第一條語句返回集合類型</typeparam> /// <typeparam name="T2">第二條語句返回集合類型</typeparam> /// <param name="sql">sql語句</param> /// <param name="param">參數化值</param> /// <returns></returns> public Tuple<IEnumerable<T1>, IEnumerable<T2>> Query<T1, T2>(string sql, object param) { IEnumerable<T1> _item1 = null; IEnumerable<T2> _item2 = null; if (!string.IsNullOrEmpty(sql)) { try { using (var multi = DbConnection.QueryMultiple(sql, param)) { _item1 = multi.Read<T1>(); _item2 = multi.Read<T2>(); } } catch { } } return Tuple.Create<IEnumerable<T1>, IEnumerable<T2>>(_item1, _item2); } /// <summary> /// 查詢一組SQL語句並返回值 /// </summary> /// <typeparam name="T1">第一條語句返回集合類型</typeparam> /// <typeparam name="T2">第二條語句返回集合類型</typeparam> /// <typeparam name="T3">第三條語句返回集合類型</typeparam> /// <param name="sql">sql語句</param> /// <param name="param">參數化值</param> /// <returns></returns> public Tuple<IEnumerable<T1>, IEnumerable<T2>, IEnumerable<T3>> Query<T1, T2, T3>(string sql, object param) { IEnumerable<T1> _item1 = null; IEnumerable<T2> _item2 = null; IEnumerable<T3> _item3 = null; if (!string.IsNullOrEmpty(sql)) { try { using (var multi = DbConnection.QueryMultiple(sql, param)) { _item1 = multi.Read<T1>(); _item2 = multi.Read<T2>(); _item3 = multi.Read<T3>(); } } catch { } } return Tuple.Create<IEnumerable<T1>, IEnumerable<T2>, IEnumerable<T3>>(_item1, _item2, _item3); } public void Dispose() { if (dbConnection != null) { try { bool isClosed = dbConnection.State == ConnectionState.Closed; if (!isClosed) dbConnection.Close(); //dbConnection.Dispose();  } catch { } } } }

調用示例如下：

 

public abstract class BaseProvide { public Lazy<LiunianContext> lazyContext; protected LiunianContextDb { get { return lazyContext.Value; } } } public class EmployeeProvide : BaseProvide { /// <summary> /// 獲取數據 /// </summary> /// <returns></returns> public List<Employee> ListEmployeeByParam(int[] param) { string sql = "select * from Employee where ID in @Ids"; return Db.Query<Employee>(sql, new { Ids = param }).ToList(); } /// <summary> /// 獲取全部數據 /// </summary> /// <returns></returns> public List<Employee> ListEmployee() { string sql = "select * from Employee"; return Db.Query<Employee>(sql,null).ToList(); } /// <summary> /// 查詢單個實體 /// </summary> /// <param name="Id"></param> /// <returns></returns> public Employee loadEmployee(int Id) { string sql = "select * from Employee where ID= @Id"; return Db.FirstOrDefault<Employee>(sql, new { Id = Id }); } /// <summary> /// 插入操作 /// </summary> /// <param name="model"></param> /// <returns></returns> public bool InsertEmployee(Employee model) { StringBuilder sql = new StringBuilder(); sql.Append("insert into Employee values (@UpdateTime,@CreateTime,@State,@LoginName,@UserName,"); sql.Append("@RoleId,@IsUse)"); return Db.Execute(sql.ToString(), model); } /// <summary> /// 更新操作 /// </summary> /// <param name="model"></param> /// <returns></returns> public bool UpdateEmployee(Employee model) { StringBuilder sql = new StringBuilder(); sql.Append("update Employee set UpdateTime = @UpdateTime where ID = @ID"); return Db.Execute(sql.ToString(), model); } /// <summary> /// 刪除操作 /// </summary> /// <param name="Id"></param> /// <returns></returns> public bool DeleteEmployeeById(int Id) { string sql = "delete from Employee where ID = @Id"; return Db.Execute(sql.ToString(), new { Id = Id }); } /// <summary> /// 執行多個語句返回多個結果 /// </summary> /// <param name="Id"></param> /// <returns></returns> public Tuple<int,IEnumerable<Employee>> ListGroupEmployee() { string sql = "select Count(*) from Employee select * from Employee"; Tuple<IEnumerable<int>, IEnumerable<Employee>> queryGroup = Db.Query<int, Employee>(sql, null); return Tuple.Create<int, IEnumerable<Employee>>(queryGroup.Item1.FirstOrDefault(),queryGroup.Item2); } }

除了沒把事務加上之外其他的增刪改查都有了，同時在傳對象的時候Dapper也解決了sql注入的問題，在性能上也是比較好的ORM框架，需要的拿去！