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;
         }

查询返回DatatTable

 /// <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;
         }

iBatisNet 1.6版本 返回DataSet

 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;
         }

利用反射返回DataSet

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;

         }

获取DbCommand

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();
                 }
             }

             ];

         }

返回DataTable

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;
                 }
             }

             ];

         }

返回DataTable，包含output参数

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