iBatis.NET是我接触Nhibernate之后的第二个ORM框架，我觉得这个框架具有小巧玲珑的特点。如果你想自己开发一个ORM框架的话，我觉得iBatis.net肯定是你必须要熟读的，因为它很简洁。如果你深入了解它，你会觉得这种ORM框架的出现是必然的，因为它很接近人们在探索ORM框架的最基本想法。
我们在自学iBatis.net的时候，都会参考NPetShop这个经典的开源代码。里面有一些核心的类，如ServiceConfig和BaseSqlMapDao，理解这些类对理解iBatis.net的核心是非常重要的。
ibatis.net组件中的核心类：
IBatisNet.DataAccess组件中的DaoManager类：
using IBatisNet.Common;
using IBatisNet.Common.Utilities;
using IBatisNet.DataAccess.Interfaces;
using IBatisNet.DataAccess.SessionStore;
using System;
using System.Collections.Specialized;
using System.Data;
using System.Reflection;
namespace IBatisNet.DataAccess
{
public class DaoManager : IDaoManager
{
public const string DEFAULT_CONTEXT_NAME = "_DEFAULT_CONTEXT_NAME";
protected static HybridDictionary DaoContextMap;
public string Id { get; set; }
public IDalSession LocalDaoSession { get; }
public IDataSource LocalDataSource { get; }
public ISessionStore SessionStore { set; }
public IDao this[Type daoInterface] { get; }
public IDalSession BeginTransaction();
public IDalSession BeginTransaction(IsolationLevel isolationLevel);
public void CloseConnection();
public void CommitTransaction();
[Obsolete("This method will be removed in a future version, use DomDaoManagerBuilder.Configure.", false)]
public static void Configure();
[Obsolete("This method will be removed in a future version, use DomDaoManagerBuilder.Configure.", false)]
public static void Configure(string resource);
[Obsolete("This method will be removed in a future version, use DomDaoManagerBuilder.Configure.", false)]
public static void ConfigureAndWatch(ConfigureHandler configureDelegate);
[Obsolete("This method will be removed in a future version, use DomDaoManagerBuilder.Configure.", false)]
public static void ConfigureAndWatch(string resource, ConfigureHandler configureDelegate);
public IDao GetDao(Type daoInterface);
public DaoSession GetDaoSession();
public static IDaoManager GetInstance();
public static IDaoManager GetInstance(IDao dao);
public static IDaoManager GetInstance(string contextName);
public bool IsDaoSessionStarted();
public IDalSession OpenConnection();
public IDalSession OpenConnection(string connectionString);
public void RollBackTransaction();
}
}
SqlMapDaoSession类：
using IBatisNet.DataAccess;
using IBatisNet.DataMapper;
using System;
using System.Data;
namespace IBatisNet.DataAccess.DaoSessionHandlers
{
public class SqlMapDaoSession : DaoSession
{
public SqlMapDaoSession(DaoManager daoManager, ISqlMapper sqlMap);
public override IDbConnection Connection { get; }
public override IDataSource DataSource { get; }
public override bool IsTransactionStart { get; }
public ISqlMapper SqlMap { get; }
public override IDbTransaction Transaction { get; }
public override void BeginTransaction();
public override void BeginTransaction(bool openConnection);
public override void BeginTransaction(IsolationLevel isolationLevel);
public override void BeginTransaction(string connectionString);
public override void BeginTransaction(bool openConnection, IsolationLevel isolationLevel);
public override void BeginTransaction(string connectionString, IsolationLevel isolationLevel);
public override void BeginTransaction(string connectionString, bool openConnection, IsolationLevel isolationLevel);
public override void CloseConnection();
public override void CommitTransaction();
public override void CommitTransaction(bool closeConnection);
public override void Complete();
public override IDbCommand CreateCommand(CommandType commandType);
public override IDbDataAdapter CreateDataAdapter();
public override IDbDataAdapter CreateDataAdapter(IDbCommand command);
public override IDbDataParameter CreateDataParameter();
public override void Dispose();
public override void OpenConnection();
public override void OpenConnection(string connectionString);
public override void RollBackTransaction();
public override void RollBackTransaction(bool closeConnection);
}
}
IBatisNet.DataMapper 组件中的DataMapper类：
using IBatisNet.Common;
using IBatisNet.Common.Utilities.Objects;
using IBatisNet.Common.Utilities.Objects.Members;
using IBatisNet.DataMapper.Configuration.Cache;
using IBatisNet.DataMapper.Configuration.ParameterMapping;
using IBatisNet.DataMapper.Configuration.ResultMapping;
using IBatisNet.DataMapper.DataExchange;
using IBatisNet.DataMapper.MappedStatements;
using IBatisNet.DataMapper.SessionStore;
using IBatisNet.DataMapper.TypeHandlers;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Data;
namespace IBatisNet.DataMapper
{
public class SqlMapper : ISqlMapper
{
public SqlMapper(IObjectFactory objectFactory, AccessorFactory accessorFactory);
public AccessorFactory AccessorFactory { get; }
public DataExchangeFactory DataExchangeFactory { get; }
public IDataSource DataSource { get; set; }
public string Id { get; }
public bool IsCacheModelsEnabled { get; set; }
public bool IsSessionStarted { get; }
public ISqlMapSession LocalSession { get; }
public HybridDictionary MappedStatements { get; }
public IObjectFactory ObjectFactory { get; }
public HybridDictionary ParameterMaps { get; }
public HybridDictionary ResultMaps { get; }
public ISessionStore SessionStore { set; }
public TypeHandlerFactory TypeHandlerFactory { get; }
public void AddCache(CacheModel cache);
public void AddMappedStatement(string key, IMappedStatement mappedStatement);
public void AddParameterMap(ParameterMap parameterMap);
public void AddResultMap(IResultMap resultMap);
public ISqlMapSession BeginTransaction();
public ISqlMapSession BeginTransaction(bool openConnection);
public ISqlMapSession BeginTransaction(IsolationLevel isolationLevel);
public ISqlMapSession BeginTransaction(string connectionString);
public ISqlMapSession BeginTransaction(bool openNewConnection, IsolationLevel isolationLevel);
public ISqlMapSession BeginTransaction(string connectionString, IsolationLevel isolationLevel);
public ISqlMapSession BeginTransaction(string connectionString, bool openNewConnection, IsolationLevel isolationLevel);
public void CloseConnection();
public void CommitTransaction();
public void CommitTransaction(bool closeConnection);
public ISqlMapSession CreateSqlMapSession();
public ISqlMapSession CreateSqlMapSession(string connectionString);
public int Delete(string statementName, object parameterObject);
public void FlushCaches();
public CacheModel GetCache(string name);
public string GetDataCacheStats();
public IMappedStatement GetMappedStatement(string id);
public ParameterMap GetParameterMap(string name);
public IResultMap GetResultMap(string name);
public object Insert(string statementName, object parameterObject);
public ISqlMapSession OpenConnection();
public ISqlMapSession OpenConnection(string connectionString);
public IDictionary QueryForDictionary(string statementName, object parameterObject, string keyProperty);
public IDictionary<K, V> QueryForDictionary<K, V>(string statementName, object parameterObject, string keyProperty);
public IDictionary QueryForDictionary(string statementName, object parameterObject, string keyProperty, string valueProperty);
public IDictionary<K, V> QueryForDictionary<K, V>(string statementName, object parameterObject, string keyProperty, string valueProperty);
public IDictionary<K, V> QueryForDictionary<K, V>(string statementName, object parameterObject, string keyProperty, string valueProperty, DictionaryRowDelegate<K, V> rowDelegate);
public IList<T> QueryForList<T>(string statementName, object parameterObject);
public IList QueryForList(string statementName, object parameterObject);
public void QueryForList<T>(string statementName, object parameterObject, IList<T> resultObject);
public void QueryForList(string statementName, object parameterObject, IList resultObject);
public IList<T> QueryForList<T>(string statementName, object parameterObject, int skipResults, int maxResults);
public IList QueryForList(string statementName, object parameterObject, int skipResults, int maxResults);
public IDictionary QueryForMap(string statementName, object parameterObject, string keyProperty);
public IDictionary QueryForMap(string statementName, object parameterObject, string keyProperty, string valueProperty);
public IDictionary QueryForMapWithRowDelegate(string statementName, object parameterObject, string keyProperty, string valueProperty, DictionaryRowDelegate rowDelegate);
public object QueryForObject(string statementName, object parameterObject);
public T QueryForObject<T>(string statementName, object parameterObject);
public object QueryForObject(string statementName, object parameterObject, object resultObject);
public T QueryForObject<T>(string statementName, object parameterObject, T instanceObject);
[Obsolete("This method will be remove in future version.", false)]
public PaginatedList QueryForPaginatedList(string statementName, object parameterObject, int pageSize);
public IList<T> QueryWithRowDelegate<T>(string statementName, object parameterObject, RowDelegate<T> rowDelegate);
public IList QueryWithRowDelegate(string statementName, object parameterObject, RowDelegate rowDelegate);
public void RollBackTransaction();
public void RollBackTransaction(bool closeConnection);
public int Update(string statementName, object parameterObject);
}
}
IBatisNet.Common组件中的IBatisNetException类，处理异常信息的类。
using System;
using System.Runtime.Serialization;
namespace IBatisNet.Common.Exceptions
{
[Serializable]
public class IBatisNetException : ApplicationException
{
public IBatisNetException();
public IBatisNetException(Exception ex);
public IBatisNetException(string message);
protected IBatisNetException(SerializationInfo info, StreamingContext context);
public IBatisNetException(string message, Exception inner);
}
}
通过列举上面的组件的类，我们大概可以分析出ibatis.net三大组件的作用：
IBatisNet.DataAccess，是访问数据库和与数据库交互的核心组件。
IBatisNet.DataMapper，提供数据访问的接口。将SQL从原来硬编码中分离到.xml文件中去。
查询出来的结果通过Map, List, Object方式返回调用层。.NET 2.0推出之后，iBatisNet的DataMapper也支持了泛型，
具有了更强的类型支持。其简单易上手的动态SQL(通过xml标签来配置)，使得iBatisNet更加灵活好用。
/// <summary>
/// iBatis.NET的核心类 ServiceConfig.
/// </summary>
public class ServiceConfig
{
static private object synRoot = new object(); //建立一个object对象，在處理多線程的同步時非常有用
//3：定义一个变量instance来存储创建好的类实例，因为这个变量要在静态方法中使用，所以需要加上static修饰
static private ServiceConfig instance;
private DaoManager daoManager = null; //定义一个DaoManager类型的daoManager字段
///<summary>
///1:私有化构造方法，好在内部控制创建实例的数目
///</summary>
private ServiceConfig() { }
//2：定义一个方法来为客户端提供类实例，这个方法需要定义成类方法(即静态方法)，也就是要加上static
static public ServiceConfig GetInstance()
{
if (instance == null)
{
//在多线程的程序中，多个线程同时访问单例类，调用GetInstance()方法，会有可能造成创建多个实例在这种情况下，给进行加一把锁来处理
//lock是确保当一个线程位于代码的临界区时，另一个线程不进入临界区。如果其他线程试图进入锁定代码，则它将一直等,直到对象被释放。
lock (synRoot)
{
//判断存储实例的变量是否有值
if (instance == null)
{
try
{
//定义ConfigureHander事件的一个实例handler，并调用Service.Reset作为参数，该事件的作用是
IBatisNet.Common.Utilities.ConfigureHandler handler = new ConfigureHandler(ServiceConfig.Reset);
IBatisNet.DataAccess.Configuration.DomDaoManagerBuilder builder = new DomDaoManagerBuilder();
builder.ConfigureAndWatch("dao.config", handler);
instance = new ServiceConfig(); //如果Instance为空，就创建一个类实例，并把值赋给存储类实例的变量instance.
//返回一个DaoManager实例，"SqlMapDao"为dao.config文件 context 节点id的值
instance.daoManager = (DaoManager)DaoManager.GetInstance("SqlMapDao");
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
}
}
}
return instance; //如果Instance不为空，那就直接使用。
}
///<summary>
///Reset the singleton
///<summary>
///<remarks>
///Must verity ConfigureHandler signature.
///</remarks>
///<param name="obj">
///</param>
static public void Reset(object obj)
{
instance = null;
}
//定义一个属性DaoManager,它返回一个DaoManager类的一个实例
public DaoManager DaoManager
{
get
{
return daoManager;
}
}
}
现在让我们看看ServiceConfig类的具体作用。下面定义一个服务类NewsService，我们通过 IbatisNet.ServiceConfig.GetInstance().DaoManager返回一个DaoManager的一个实例。再通过这个实例进行对数据库的操作。
public class NewsService
{
#region Private Fields
private INewsDao newsDao;
private static NewsService instance = new NewsService();
private DaoManager daoManager = null;
#endregion
public static NewsService GetInstance()
{
return instance;
}
public NewsService()
{
daoManager = IbatisNet.ServiceConfig.GetInstance().DaoManager;
newsDao = daoManager.GetDao(typeof(INewsDao)) as INewsDao;
}
public object InsertNews(Domain.News news)
{
return this.newsDao.InsertNews(news);
}
public Domain.News GetNewsById(float? newsId)
{
return this.newsDao.GetNewsById(newsId);
}
public IList<Domain.News> GetNewsList()
{
return this.newsDao.GetNewsList();
}
public IList<Domain.News> GetNewsListByParameter(Parameter.NewsParameter newsParameter)
{
return this.newsDao.GetNewsListByParameter(newsParameter);
}
public IList<Domain.News> GetNewsListByAnyWhere(string strQueryString)
{
Parameter.NewsParameter newsParameter = new Parameter.NewsParameter();
newsParameter.UnlimitedQuery = strQueryString;
return this.newsDao.GetNewsListByAnyWhere(newsParameter);
}
public int UpdateNews(Domain.News news)
{
return this.newsDao.UpdateNews(news);
}
public int UpdateNewsByParameter(Parameter.NewsParameter newsParameter)
{
return this.newsDao.UpdateNewsByParameter(newsParameter);
}
public object DeleteNews(Domain.News news)
{
return this.newsDao.DeleteNews(news);
}
public object DeleteNewsById(float? newsId)
{
return this.newsDao.DeleteNewsById(newsId);
}
public object DeleteNewsByParameter(Parameter.NewsParameter newsParameter)
{
return this.newsDao.DeleteNewsByParameter(newsParameter);
}
public object DeleteNewsByAnyWhere(Parameter.NewsParameter newsParameter)
{
return this.newsDao.DeleteNewsByAnyWhere(newsParameter);
}
}
自定义的BaseSqlMapDao类，数据库操作类，类似于OracleHelper后SqlHelper。
using System;
using System.Collections.Generic;
using IBatisNet.DataMapper;
using IBatisNet.DataAccess;
using IBatisNet.DataAccess.DaoSessionHandlers;
using IBatisNet.Common.Exceptions;
namespace ESPS.IbatisNet
{
/// <summary>
/// 基于IBatisNet的数据访问基类
/// </summary>
public class BaseSqlMapDao : IBatisNet.DataAccess.Interfaces.IDao
{
protected const int PAGE_SIZE = 4;
///<summary>
/// Looks up the parent DaoManager, gets the local transaction
/// (which should be a SqlMapDaoTransaction) and returns the
/// SqlMap associated with this DAO.
///</summary>
///<returns>The SqlMap instance for this DAO.</returns>
protected IBatisNet.DataMapper.SqlMapper GetLocalSqlMap()
{
IBatisNet.DataAccess.DaoManager daoManager = (DaoManager)DaoManager.GetInstance(this);//this 向上转型为IDao类型的实例，通过GetInstance返回一个IDaoManager的实例，再向下转型为DaoManager的一个实例
IBatisNet.DataAccess.DaoSessionHandlers.SqlMapDaoSession sqlMapDaoSession = (SqlMapDaoSession)daoManager.LocalDaoSession;
return (IBatisNet.DataMapper.SqlMapper)sqlMapDaoSession.SqlMap; //向下转型，强制执行
}
///<summary>
///Simple convenience method to wrap the SqlMap method of the same name.
///Warps the exception with a IBatisNetException to isolate the SqlMap framework.
/// </summary>
/// <typeparam name="T">实体类型</typeparam>
/// <param name="statementName">操作名称，对应xml中的Statement的id</param>
/// <param name="parameterObject">参数</param>
/// <returns></returns>
protected IList<T> ExecuteQueryForList<T>(string statementName, object parameterObject)
{
SqlMapper sqlMap = GetLocalSqlMap();
try
{
return sqlMap.QueryForList<T>(statementName, parameterObject);
}
catch (Exception e)
{
throw new IBatisNetException("Error executing query '" + statementName + "'for list. Cause: " + e.Message, e);
}
}
/// <summary>
/// Simple convenience method to wrap the SqlMap method of the same name.
/// Wraps the exception with a IBatisNetException to isolate the SqlMap framework.
/// 得到指定数量的记录数
/// </summary>
/// <param name="statementName"></param>
/// <param name="parameterObject">参数</param>
/// <param name="skipResults">跳过的记录数</param>
/// <param name="maxResults">最大返回的记录数</param>
/// <returns></returns>
protected IList<T> ExecuteQueryForList<T>(string statementName, object parameterObject, int skipResults, int maxResults)
{
SqlMapper sqlMap = GetLocalSqlMap();
try
{
return sqlMap.QueryForList<T>(statementName, parameterObject, skipResults, maxResults);
}
catch (Exception e)
{
throw new IBatisNetException("Error executing query '" + statementName + "' for list. Cause: " + e.Message, e);
}
}
/// <summary>
/// Simple convenience method to wrap the SqlMap method of the same name.
/// Wraps the exception with a IBatisNetException to isolate the SqlMap framework.
/// 查询得到对象的一个实例
/// </summary>
/// <typeparam name="T">对象type</typeparam>
/// <param name="statementName">操作名</param>
/// <param name="parameterObject">参数</param>
/// <returns></returns>
protected T ExecuteQueryForObject<T>(string statementName, object parameterObject)
{
SqlMapper sqlMap = GetLocalSqlMap();
try
{
return sqlMap.QueryForObject<T>(statementName, parameterObject);
}
catch (Exception e)
{
throw new IBatisNetException("Error executing query '" + statementName + "' for object. Cause: " + e.Message, e);
}
}
/// <summary>
///
/// </summary>
/// <param name="statementName"></param>
/// <param name="parameterObject"></param>
/// <param name="keyProperty"></param>
/// <param name="valueProperty"></param>
/// <returns></returns>
protected object ExecuteQueryForMap(string statementName, string parameterObject, string keyProperty, string valueProperty)
{
SqlMapper sqlMap = GetLocalSqlMap();
try
{
return sqlMap.QueryForMap(statementName, parameterObject, keyProperty, valueProperty);
}
catch (Exception e)
{
throw new IBatisNetException("Error executing query '" + statementName + "' for object. Cause: " + e.Message, e);
}
}
protected object ExecuteQueryForMap(string statementName, object parameterObject, string keyProperty)
{
SqlMapper sqlMap = GetLocalSqlMap();
try
{
return sqlMap.QueryForMap(statementName, parameterObject, keyProperty);
}
catch (Exception e)
{
throw new IBatisNetException("Error executing query '" + statementName + "' for object. Cause: " + e.Message, e);
}
}
/// <summary>
/// Simple convenience method to wrap the SqlMap method of the same name.
/// Wraps the exception with a IBatisNetException to isolate the SqlMap framework.
/// 执行修改
/// </summary>
/// <param name="statementName">操作名</param>
/// <param name="parameterObject">参数</param>
/// <returns></returns>
protected int ExecuteUpdate(string statementName, object parameterObject)
{
SqlMapper sqlMap = GetLocalSqlMap();
try
{
return sqlMap.Update(statementName, parameterObject);
}
catch (Exception e)
{
throw new IBatisNetException("Error executing query'" + statementName + "' for update. Cause: " + e.Message, e);
}
}
/// <summary>
/// Simple convenience method to wrap the SqlMap method of the same name.
/// Wraps the exception with a IBatisNetException to isolate the SqlMap framework.
/// 执行插入
/// </summary>
/// <param name="statementName">操作名</param>
/// <param name="parameterObject">参数</param>
/// <returns></returns>
protected object ExecuteInsert(string statementName, object parameterObject)
{
SqlMapper sqlMap = GetLocalSqlMap();
try
{
return sqlMap.Insert(statementName, parameterObject);
}
catch (Exception e)
{
throw new IBatisNetException("Error executing query '" + statementName + "' for insert. Cause: " + e.Message, e);
}
}
/// <summary>
/// 执行删除
/// </summary>
/// <param name="statementName">操作名</param>
/// <param name="parameterObject">参数</param>
/// <returns>返回影响行数</returns>
protected object ExecuteDelete(string statementName, Object parameterObject)
{
SqlMapper sqlMap = GetLocalSqlMap();
try
{
return sqlMap.Delete(statementName, parameterObject);
}
catch (Exception e)
{
throw new IBatisNetException("Error executing query '" + statementName + "' for delete. Cause: " + e.Message, e);
}
}
}
}