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perfect DAO design - related classes

package afu.framework;

import java.sql.Connection;
import java.lang.reflect.Constructor;

import afu.framework.service.*;
import afu.framework.action.*;
import afu.framework.util.SysLogger;
import afu.framework.config.ModuleConfig;
import afu.framework.jdbc.BaseDao;

public class BeanFactory
{
    private BeanFactory()
    {        
    }
    
    public static BaseService newService(String beanId) 
    {
        if(beanId==null)
        {
            SysLogger.error("beanId can not be null.");
            return null;
        }        
        if(!ModuleConfig.getServicesMap().containsKey(beanId))
        {
            SysLogger.error("Service-class whose id is " + beanId + " doest not exist.");
            return null;
        }                
        BaseService bs = null;
        try
        {
            ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
            if (classLoader == null) 
                classLoader = BeanFactory.class.getClassLoader();
        
            Class clazz = classLoader.loadClass(ModuleConfig.getServicesMap().get(beanId));
            bs = (BaseService)clazz.newInstance();
        }
        catch(Exception e)
        {
            SysLogger.error("BeanFacade.newService()",e);
        }
        return bs;
    }
        
    @SuppressWarnings("unchecked")
    public static BaseAction newAction(String beanId) 
    {
        if(beanId==null)
        {
            SysLogger.error("beanId can not be null.");
            return null;
        }
        if(!ModuleConfig.getActionsMap().containsKey(beanId))
        {
            SysLogger.error("Action-class whose id is " + beanId + " doest not exist.");
            return null;
        }
        BaseAction ba = null;
        try
        {
            ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
            if (classLoader == null) 
               classLoader = BeanFactory.class.getClassLoader();
        
            Class clazz = classLoader.loadClass(ModuleConfig.getActionsMap().get(beanId));
            ba = (BaseAction)clazz.newInstance();
        }
        catch(Exception e)
        {
            SysLogger.error("BeanFacade.getAction()",e);
        }
        return ba;
    }  
    
    public static BaseDao newDao(String beanId)
    {
        return newDao(beanId,null);
    }
    
    public static BaseDao newDao(String beanId,Connection conn)
    {
        if(beanId==null || !ModuleConfig.getDaosMap().containsKey(beanId))
            return null;

        BaseDao dao = null;
        try
        {
            Class[] types = new Class[] { java.sql.Connection.class };
            Class clazz = Class.forName(ModuleConfig.getDaosMap().get(beanId));
            Constructor cons = clazz.getConstructor(types);
            Object[] args = new Object[] {conn};
            dao = (BaseDao)cons.newInstance(args);
        }
        catch(Exception e)
        {
            SysLogger.error("BeanFactory.newDao with a connection",e);
        }
        return dao;
    }
}

package afu.framework.jdbc;

import java.util.*;
import java.sql.*;

import javax.naming.*;
import javax.sql.DataSource;

import afu.framework.util.SysLogger;

import afu.framework.config.ModuleConfig;


public class ConnectionManager
{
   private ConnectionManager() 
   {       
   }
   
   private static Map<String,DataSource> dsMap;   
   static
   {
       dsMap = new HashMap<String,DataSource>();
       List<String> jndis = ModuleConfig.getJndis();
       try
       {
          Context initCtx = new InitialContext();
          if("weblogic".equalsIgnoreCase(ModuleConfig.getContainer()))
          {
              for(String jndi:jndis)
              {                
                  DataSource ds = (DataSource)initCtx.lookup(jndi);
                   dsMap.put(jndi,ds);
              }
          }
          else
          {
              for(String jndi:jndis)
              {                
                  DataSource ds = (DataSource)initCtx.lookup("java:comp/env/" + jndi);
                   dsMap.put(jndi,ds);
              }              
          }
          initCtx.close();
       }
       catch(NamingException e)
       {
           SysLogger.error("Can not connect database,may be jndi does not exist",e);
       }
       catch(Exception e)
       {
           SysLogger.error("Can not connect database",e);
       }
   }
   
   public static Connection getConnection()
   {
       return getConnection(ModuleConfig.getDefaultJndi(),true);
   }
   
   public static Connection getConnection(final boolean autoCommit)
   {
       return getConnection(ModuleConfig.getDefaultJndi(),autoCommit);
   }
   
   public static Connection getConnection(final String jndi,final boolean autoCommit)
   {
       Connection conn = null;
       try
       {           
           DataSource ds = dsMap.get(jndi);
           if(ds==null) return null;
           
           conn = ds.getConnection();           
           conn.setAutoCommit(autoCommit);
       }
       catch(SQLException sqle)
       {
           SysLogger.error("Database fail to get connection 1",sqle);
       }
       catch(Exception sqle)
       {
           SysLogger.error("Database fail to get connection 2",sqle);
       }
       return conn;
   }
   
   public static void close(Connection conn)
   {
       try
       {
           if(conn!=null && !conn.isClosed())
              conn.close();
       }
       catch(SQLException se)
       {
           SysLogger.error("Fail to close() connection",se);         
       }
   }

   public static void close(Connection conn,Statement stmt,ResultSet rs)
   {
       try
       {
           if(conn!=null && !conn.isClosed())
              conn.close();
           if(stmt!=null)
              stmt.close();
           if(rs!= null)
              rs.close();           
       }
       catch(SQLException se)
       {
           SysLogger.error("Fail to close() connection",se);         
       }
   }
   
   public static void rollback(Connection conn)
   {
       try
       {
           if(!conn.getAutoCommit())             
              conn.rollback();
       }
       catch(SQLException se)
       {
           SysLogger.error("Can not do rollback operation.",se);         
       }
   }   
} 

posted on 2007-05-12 12:37 afunms 阅读(123) 评论(0)  编辑  收藏


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