IBatis.Net使用总结（二）-- IBatis返回DataTable/DataSet（网上例子的集合）

IBatis返回DataTable，DataSet

ibatis.net QueryForDataTable

　　完整的为ibatis.net 引入datatable支持要改动很多地方,所以描述的是最小化的改动.不过我们可以大概了解一下比较完整的集成要做那些事情.

　　ibatis.net 的基本运行原理就是获得一个reader后,然后进行循环,对每条记录使用ResultStrategy中的对应实现进行处理,然后返回到结果集.因此,首先,需要实现一个DataTableStrategy 用来为每条记录产生一个新DataRow. 大家可以看到,下面的实现已经绕开了ibatis.net的处理逻辑.

　　你可以在网上google到一些ibatis返回dataset的代码,可在最新的版本1.6 ibatis.net 这些代码都无法工作,这是因为RequestScope.IDbCommand现在返回的是一个DbCommandDecorator对象实例(一个实现IDbCommand接口并代理一个具体的IDbCommand实现的对象),而DataAdapter的实现,需要对应的idbcommand实现,如 SqlDataAdapter需要SqlCommand.因此,如下代码会导致cast错误

Mapper.LocalSession.CreateDataAdapter(scope.IDbCommand).Fill(dataTable);

这里有两种解法,一是使用datatable.Load方法来装载IDbCommand.ExecuteReader的返回结果,这是可行的

其次是利用反射,实际的idbcommand在DbCommandDecorator中被保存为_innerDbCommand field ,下面是两种实现. 大约的感觉,如果你在意性能的话,第一种会快些

        /// <summary>
        /// 查询返回DatatTable
        /// </summary>
        /// <param name="statementName"></param>
        /// <param name="parameterObject"></param>
        /// <returns></returns>
        public DataTable QueryForDataTable(string statementName, object parameterObject)
        {
            bool isSessionLocal = false;
            ISqlMapSession session = SqlMap.LocalSession;
            DataTable dataTable = null;
            if (session == null)
            {
                session = SqlMap.CreateSqlMapSession();
                isSessionLocal = true;
            }
            try
            {
                IMappedStatement statement = SqlMap.GetMappedStatement(statementName);
                dataTable = new DataTable(statementName);
                RequestScope request = statement.Statement.Sql.GetRequestScope(statement, parameterObject, session);
                statement.PreparedCommand.Create(request, session, statement.Statement, parameterObject);
                using (request.IDbCommand)
                {
                    dataTable.Load(request.IDbCommand.ExecuteReader());
                }
            }
            catch
            {
                throw;
            }
            finally
            {
                if (isSessionLocal)
                {
                    session.CloseConnection();
                }
            }
            return dataTable;
        }

/// <summary>
        /// iBatisNet 1.6版本 返回DataSet
        /// </summary>
        /// <param name="statementName"></param>
        /// <param name="paramObject"></param>
        /// <returns></returns>
        public DataSet QueryForDataSet(string statementName, object paramObject)
        {
            DataSet ds = new DataSet();
            ISqlMapper mapper = Mapper.Instance();
            IMappedStatement statement = mapper.GetMappedStatement(statementName);
            if (!mapper.IsSessionStarted)
            {
                mapper.OpenConnection();
            }
            RequestScope scope = statement.Statement.Sql.GetRequestScope(statement, paramObject, mapper.LocalSession);
            statement.PreparedCommand.Create(scope, mapper.LocalSession, statement.Statement, paramObject);
            IDbCommand command = mapper.LocalSession.CreateCommand(CommandType.Text);
            command.CommandText = scope.IDbCommand.CommandText;
            foreach (IDataParameter pa in scope.IDbCommand.Parameters)
            {
                command.Parameters.Add(new SqlParameter(pa.ParameterName, pa.Value));
            }
            mapper.LocalSession.CreateDataAdapter(command).Fill(ds);
            return ds;
        }

public DataSet QueryForDataSet2(string statementName, object parameterObject)
        {
            bool isSessionLocal = false;
            ISqlMapSession session = _sessionStore.LocalSession;
            DataSet ds = new DataSet(statementName);
            if (session == null)
            {
                session = CreateSqlMapSession();
                isSessionLocal = true;
            }
            try
            {
                IMappedStatement statement = GetMappedStatement(statementName);
                RequestScope request = statement.Statement.Sql.GetRequestScope(statement, parameterObject, session);
                statement.PreparedCommand.Create(request, session, statement.Statement, parameterObject);
                FieldInfo info = request.IDbCommand.GetType().GetField("_innerDbCommand", BindingFlags.NonPublic | BindingFlags.Instance);
                using (IDbCommand cmd = (IDbCommand)info.GetValue(request.IDbCommand))
                {
                    session.CreateDataAdapter(cmd).Fill(ds);
                }
 
            }
            catch
            {
                throw;
            }
            finally
            {
                if (isSessionLocal)
                {
                    session.CloseConnection();
                }
            }
            return ds;
        }

以下是1.6.1版本之前返回DataTable的方法。

private IDbCommand GetDbCommand(string statementName, object paramObject)
        {
            IStatement statement = sqlMap.GetMappedStatement(statementName).Statement;

            IMappedStatement mapStatement = sqlMap.GetMappedStatement(statementName);

            IDalSession session = new SqlMapSession(sqlMap);

            if (sqlMap.LocalSession != null)
            {
                session = sqlMap.LocalSession;
            }
            else
            {
                session = sqlMap.OpenConnection();
            }

            RequestScope request = statement.Sql.GetRequestScope(mapStatement, paramObject, session);

            mapStatement.PreparedCommand.Create(request, session, statement, paramObject);

            return request.IDbCommand;

        }

这种返回DataTable的方式，容易引起Sql注入，因为xml文件中，sql语句需要使用$作为占位符。

        /// <summary>
        /// 通用的以DataTable的方式得到Select的结果(xml文件中参数要使用$标记的占位参数)
        /// </summary>
        /// <param name="statementName">语句ID</param>
        /// <param name="paramObject">语句所需要的参数</param>
        /// <returns>得到的DataTable</returns>
        protected DataTable ExecuteQueryForDataTable(string statementName, object paramObject)
        {
            DataSet ds = new DataSet();
            bool isSessionLocal = false;
            IDalSession session = sqlMap.LocalSession;
            if (session == null)
            {
                session = new SqlMapSession(sqlMap);
                session.OpenConnection();
                isSessionLocal = true;
            }

            IDbCommand cmd = GetDbCommand(statementName, paramObject);

            try
            {
                cmd.Connection = session.Connection;
                IDbDataAdapter adapter = session.CreateDataAdapter(cmd);
                adapter.Fill(ds);
            }
            finally
            {
                if (isSessionLocal)
                {
                    session.CloseConnection();
                }
            }

            return ds.Tables[0];

        }

如果参数中，包含有output参数，则使用下面的方法

/// <summary>
        /// 通用的以DataTable的方式得到Select的结果(xml文件中参数要使用$标记的占位参数)
        /// </summary>
        /// <param name="statementName">语句ID</param>
        /// <param name="paramObject">语句所需要的参数</param>
    /// <param name="htOutPutParameter)">Output参数值哈希表</param>
        /// <returns>得到的DataTable</returns>
        protected DataTable ExecuteQueryForDataTable(string statementName, object paramObject, out Hashtable htOutPutParameter)
        {
            DataSet ds = new DataSet();
            bool isSessionLocal = false;
            IDalSession session = sqlMap.LocalSession;
            if (session == null)
            {
                session = new SqlMapSession(sqlMap);
                session.OpenConnection();
                isSessionLocal = true;
            }

            IDbCommand cmd = GetDbCommand(statementName, paramObject);

            try
            {
                cmd.Connection = session.Connection;
                IDbDataAdapter adapter = session.CreateDataAdapter(cmd);
                adapter.Fill(ds);
            }
            finally
            {
                if (isSessionLocal)
                {
                    session.CloseConnection();
                }
            }

            foreach (IDataParameter parameter in cmd.Parameters)
            {
                if (parameter.Direction == ParameterDirection.Output)
                {
                    htOutPutParameter[parameter.ParameterName] = parameter.Value;
                }
            }

            return ds.Tables[0];

        }

参考链接：

原文地址：ibatis 返回DataTable和DataSet作者：happytor

原文地址：[IBatisNet]关于返回DataTable的一点问题 作者：Daniel Pang