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分享DbHelper重装上阵
看了以前写过的代码，拿来修改了下，下贴出来，大家看看有什么问题，或者哪里需要改进的，哈哈，互相促进
1、Configuration类
1、Configuration类
using System;
using System.Collections;
using System.Collections.Generic;
using System.Configuration;
using System.IO;
using System.Xml;
using System.Reflection;
namespace LBC.Data
{
/// <summary>
/// LBC.Data配置类，负责读取配置，创建<see cref="LBC.Data.DbProviderFactory"/>
/// </summary>
public class Configuration
{
private static string GetDefaultConfigurationFilePath()
{
string baseDir = AppDomain.CurrentDomain.BaseDirectory;
string relativeSearchPath = AppDomain.CurrentDomain.RelativeSearchPath;
string binPath = relativeSearchPath == null ? baseDir : Path.Combine(baseDir, relativeSearchPath);
return Path.Combine(binPath, Environment.DefaultCfgFileName);
}
private DbProviderFactory BuildProviderFactory(IDictionary<string, string> settings)
{
return new DbProviderFactory(settings);
}
private IDictionary<string, string> GetSettings(XmlReader reader)
{
IDictionary<string, string> settings = new Dictionary<string, string>();
XmlDocument document = new XmlDocument();
document.Load(reader);
XmlNodeList list = document.SelectNodes("//" + Environment.SectionName + "/add");
foreach (XmlNode node in list)
{
settings[node.Attributes["key"].Value] = node.Attributes["value"].Value;
}
return settings;
}
public DbProviderFactory BuildProviderFactory()
{
IDictionary<string, string> settings = new Dictionary<string, string>();
Hashtable ht = ConfigurationManager.GetSection(Environment.SectionName) as Hashtable;
if (ht != null)
{
foreach (string key in ht.Keys)
{
settings[key] = ht[key].ToString();
}
return BuildProviderFactory(settings);
}
else
{
return BuildProviderFactory(GetDefaultConfigurationFilePath());
}
}
public DbProviderFactory BuildProviderFactory(string fileName)
{
XmlTextReader reader = null;
try
{
reader = new XmlTextReader(fileName);
return BuildProviderFactory(reader);
}
finally
{
if (reader != null)
{
reader.Close();
}
}
}
public DbProviderFactory BuildProviderFactory(Assembly assembly, string resourceName)
{
Stream stream = null;
try
{
stream = assembly.GetManifestResourceStream(resourceName);
if (stream == null)
{
throw new Exception("在程序集"+assembly.FullName+"中，不能创建"+resourceName+"资源");
}
return BuildProviderFactory(new XmlTextReader(stream));
}
finally
{
if (stream != null)
{
stream.Close();
}
}
}
public DbProviderFactory BuildProviderFactory(XmlReader reader)
{
IDictionary<string, string> settings = GetSettings(reader);
return BuildProviderFactory(settings);
}
}
}
...全文
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wwfgu00ing 2010-07-23
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ff1222 2010-07-23
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mark
lawbc 2010-07-23
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5、3种常见数据库类型的实现
3个类名有错，后缀应该是Driver
3个类名有错，后缀应该是Driver
happy664618843 2010-07-23
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牛B 帮顶 学习
yby881109 2010-07-23
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真的很好。。以后在项目里很有用。。
lawbc 2010-07-23
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8、DriverProxy类
/// <summary>
/// IDriver代理类
/// </summary>
public class DriverProxy:IDriver
{
private IDriver driver;
private IDictionary<string, string> settings;
public DriverProxy(IDriver driver, IDictionary<string, string> settings)
{
this.driver = driver;
this.settings = settings;
}
#region IDriver 成员
public IDbCommand CreateCommand()
{
IDbCommand command = driver.CreateCommand();
if (command != null)
{
string timeout = string.Empty;
if (settings.TryGetValue(Environment.CommandTimeoutSectionName, out timeout))
{
if (!string.IsNullOrEmpty(timeout))
{
try
{
int commandTimeout = int.Parse(timeout);
if (commandTimeout > 0)
{
command.CommandTimeout = commandTimeout;
}
}
catch(InvalidCastException e)
{
throw new LBCDataException(Environment.CommandTimeoutSectionName + "设定值必须可以转换为int类型", e);
}
}
}
}
return command;
}
public IDbConnection CreateConnection()
{
IDbConnection connection = driver.CreateConnection();
if (connection != null)
{
string connectionString = string.Empty;
if (settings.TryGetValue(Environment.ConnectionStringSectionName, out connectionString))
{
if (!string.IsNullOrEmpty(connectionString))
{
connection.ConnectionString = connectionString;
}
else
{
throw new LBCDataException(Environment.ConnectionStringSectionName + "值不能为空");
}
}
}
return connection;
}
public IDbDataAdapter CreateDataAdapter()
{
return driver.CreateDataAdapter();
}
public IDataParameter CreateParameter()
{
return driver.CreateParameter();
}
#endregion
}
lawbc 2010-07-23
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7、DbProviderFactory类
public class DbProviderFactory
{
private IDictionary<string, string> settings;
public DbProviderFactory(IDictionary<string, string> settings)
{
this.settings = settings;
}
public IDbProvider GetDbProvider()
{
string driverClass = string.Empty;
if (settings.TryGetValue(Environment.DriverClassSectionName, out driverClass))
{
try
{
IDriver driver = Activator.CreateInstance(Type.GetType(settings[Environment.DriverClassSectionName])) as IDriver;
DriverProxy driverProxy = new DriverProxy(driver, settings);
return new DbProvider(driverProxy);
}
catch(Exception e)
{
throw new LBCDataException("从" + Environment.DriverClassSectionName + "中创建IDriver类型失败。", e);
}
}
else
{
throw new LBCDataException("找不到"+Environment.DriverClassSectionName+"的设置。");
}
}
}
notfoundme 2010-07-23
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兄弟，顶一个！学习...
lawbc 2010-07-22
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6、IDbProvider实现类
/// <summary>
/// 数据库操作类，支持多数据库
/// </summary>
public class DbProvider : IDbProvider
{
private IDriver driver;
public DbProvider(IDriver driver)
{
this.driver = driver;
}
#region private utility methods & constructors
private void AttachParameters(IDbCommand command, IDataParameter[] parameters)
{
if (command == null)
{
throw new ArgumentNullException("command不能为空。");
}
if (parameters != null)
{
foreach (IDataParameter p in parameters)
{
if (p != null)
{
if ((p.Direction == ParameterDirection.InputOutput || p.Direction == ParameterDirection.Input) && (p.Value == null))
{
p.Value = DBNull.Value;
}
command.Parameters.Add(p);
}
}
}
}
private void PrepareCommand(IDbCommand command, IDbConnection connection, IDbTransaction transaction, CommandType commandType,
string commandText, IDataParameter[] parameters, out bool mustCloseConnection)
{
if (command == null) throw new ArgumentNullException("command不能为空。");
if (string.IsNullOrEmpty(commandText)) throw new ArgumentNullException("commandText不能为空。");
if (connection.State != ConnectionState.Open)
{
mustCloseConnection = true;
connection.Open();
}
else
{
mustCloseConnection = false;
}
command.Connection = connection;
command.CommandText = commandText;
if (transaction != null)
{
if (transaction.Connection == null) throw new ArgumentException("事务已提交或回滚。", "transaction");
command.Transaction = transaction;
}
command.CommandType = commandType;
if (parameters != null)
{
AttachParameters(command, parameters);
}
return;
}
#endregion private utility methods & constructors
public int ExecuteNonQuery(CommandType commandType, string commandText, params IDataParameter[] parameters)
{
using (IDbConnection connection = driver.CreateConnection())
{
IDbCommand cmd = driver.CreateCommand();
bool mustCloseConnection = false;
PrepareCommand(cmd, connection, (IDbTransaction)null, commandType, commandText, parameters, out mustCloseConnection);
int retval = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
if (mustCloseConnection)
connection.Close();
return retval;
}
}
public DataSet ExecuteDataset(CommandType commandType, string commandText, params IDataParameter[] parameters)
{
using (IDbConnection connection = driver.CreateConnection())
{
IDbCommand cmd = driver.CreateCommand();
bool mustCloseConnection = false;
PrepareCommand(cmd, connection, (IDbTransaction)null, commandType, commandText, parameters, out mustCloseConnection);
IDbDataAdapter da = driver.CreateDataAdapter();
DataSet ds = new DataSet();
da.SelectCommand = cmd;
da.Fill(ds);
cmd.Parameters.Clear();
if (mustCloseConnection)
connection.Close();
return ds;
}
}
public IDataReader ExecuteReader(CommandType commandType, string commandText, params IDataParameter[] parameters)
{
IDbConnection connection = null;
try
{
bool canClear = true;
bool mustCloseConnection = false;
connection = driver.CreateConnection();
IDbCommand cmd = driver.CreateCommand();
PrepareCommand(cmd, connection, null, commandType, commandText, parameters, out mustCloseConnection);
IDataReader dataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
foreach (IDataParameter commandParameter in cmd.Parameters)
{
if (commandParameter.Direction != ParameterDirection.Input)
canClear = false;
}
if (canClear)
{
cmd.Parameters.Clear();
}
return dataReader;
}
catch
{
if (connection != null) connection.Close();
throw;
}
}
public object ExecuteScalar(CommandType commandType, string commandText, params IDataParameter[] parameters)
{
using (IDbConnection connection = driver.CreateConnection())
{
IDbCommand cmd = driver.CreateCommand();
bool mustCloseConnection = false;
PrepareCommand(cmd, connection, (IDbTransaction)null, commandType, commandText, parameters, out mustCloseConnection);
object retval = cmd.ExecuteScalar();
cmd.Parameters.Clear();
if (mustCloseConnection)
connection.Close();
return retval;
}
}
}
lawbc 2010-07-22
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5、3种常见数据库类型的实现
public class OdbcProvider : IDriver
{
#region IDriver 成员
public IDbCommand CreateCommand()
{
return new OdbcCommand();
}
public IDbConnection CreateConnection()
{
return new OdbcConnection();
}
public IDbDataAdapter CreateDataAdapter()
{
return new OdbcDataAdapter();
}
public IDataParameter CreateParameter()
{
return new OdbcParameter();
}
#endregion
}
public class OleDbProvider : IDriver
{
#region IDriver 成员
public IDbCommand CreateCommand()
{
return new OleDbCommand();
}
public IDbConnection CreateConnection()
{
return new OleDbConnection();
}
public IDbDataAdapter CreateDataAdapter()
{
return new OleDbDataAdapter();
}
public IDataParameter CreateParameter()
{
return new OleDbParameter();
}
#endregion
}
public class SqlClientProvider : IDriver
{
#region IDriver 成员
public IDbCommand CreateCommand()
{
return new SqlCommand();
}
public IDbConnection CreateConnection()
{
return new SqlConnection();
}
public IDbDataAdapter CreateDataAdapter()
{
return new SqlDataAdapter();
}
public IDataParameter CreateParameter()
{
return new SqlParameter();
}
#endregion
}
lawbc 2010-07-22
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4、IDriver接口和IDbProvider接口
/// <summary>
/// 提供数据操作方法
/// </summary>
public interface IDbProvider
{
int ExecuteNonQuery(CommandType commandType, string commandText, params IDataParameter[] parameters);
DataSet ExecuteDataset(CommandType commandType, string commandText, params IDataParameter[] parameters);
IDataReader ExecuteReader(CommandType commandType, string commandText, params IDataParameter[] parameters);
object ExecuteScalar(CommandType commandType, string commandText, params IDataParameter[] parameters);
}
/// <summary>
/// 提供创建数据连接对象、命令对象、适配器对象、参数对象
/// </summary>
public interface IDriver
{
/// <summary>
/// 创建数据库命令对象
/// </summary>
/// <returns></returns>
IDbCommand CreateCommand();
/// <summary>
/// 创建数据库连接对象
/// </summary>
/// <returns></returns>
IDbConnection CreateConnection();
/// <summary>
/// 创建数据库适配器，用于填充DataSet对象
/// </summary>
/// <returns></returns>
IDbDataAdapter CreateDataAdapter();
/// <summary>
/// 创建数据库参数
/// </summary>
/// <returns></returns>
IDataParameter CreateParameter();
}
dengNeeo 2010-07-22
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mark
我一般不这么写
没到这么的高度
我一般不这么写
没到这么的高度
lawbc 2010-07-22
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3、LBCException 类
/// <summary>
/// LBC.Data异常类
/// </summary>
public class LBCException : Exception
{
public LBCException() : base("LBCException异常") { }
public LBCException(string message) : base(message) { }
protected LBCException(SerializationInfo info, StreamingContext context) : base(info, context) { }
public LBCException(string message, Exception innerException) : base(message, innerException) { }
}
lawbc 2010-07-22
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2、Environment类
/// <summary>
/// LBC.Data全局类，保存一些全局参数变量
/// </summary>
public sealed class Environment
{
public const string DefaultCfgFileName = "LBC.Data.xml";
public const string SectionName = "lbc-configuration/dataSource";
public const string DriverClassSectionName = "driverClass";
public const string ConnectionStringSectionName = "connectionString";
public const string CommandTimeoutSectionName = "commandTimeout";
}
