connectionfactory.java

用java写一个线程池的例子,值得一看.

/**
 * Created by IntelliJ IDEA.
 * User: Administrator
 * Date: 2008-1-10
 * Time: 15:58:01
 * To change this template use Options | File Templates.
 */

import javax.sql.DataSource;
import javax.naming.NameNotFoundException;
import javax.naming.NameAlreadyBoundException;
import java.util.Hashtable;
import java.sql.SQLException;

/**
* 连接池类厂，该类常用来保存多个数据源名称合数据库连接池对应的哈希
* @author liusoft
*/

public class ConnectionFactory {

//该哈希表用来保存数据源名和连接池对象的关系表
    static Hashtable connectionPools = null;
    static{
        connectionPools = new Hashtable(2,0.75F);
    }

/**
  * 从连接池工厂中获取指定名称对应的连接池对象
  * @param dataSource 连接池对象对应的名称
  * @return DataSource 返回名称对应的连接池对象
  * @throws NameNotFoundException 无法找到指定的连接池
  */
public static DataSource lookup(String dataSource)
  throws NameNotFoundException
{
    Object ds = null;
    ds = connectionPools.get(dataSource);
    if(ds == null || !(ds instanceof DataSource))
        throw new NameNotFoundException(dataSource);
    return (DataSource)ds;
}

    /**
      * 将指定的名字和数据库连接配置绑定在一起并初始化数据库连接池
      * @param name  对应连接池的名称
      * @param param 连接池的配置参数，具体请见类ConnectionParam
      * @return DataSource 如果绑定成功后返回连接池对象
      * @throws NameAlreadyBoundException 一定名字name已经绑定则抛出该异常
      * @throws ClassNotFoundException  无法找到连接池的配置中的驱动程序类
      * @throws IllegalAccessException  连接池配置中的驱动程序类有误
      * @throws InstantiationException  无法实例化驱动程序类
      * @throws SQLException    无法正常连接指定的数据库
      */
    public static DataSource bind(String name, ConnectionParam param)
      throws Exception,ClassNotFoundException,
        IllegalAccessException,InstantiationException,SQLException
    {
      DataSourceImpl source = null;
      try{
       lookup(name);
       throw new NameAlreadyBoundException(name);
      }catch(NameNotFoundException e){
       source = new DataSourceImpl(param);
          try {
              source.initConnection();
          }catch(Exception ex){
             throw new Exception(ex.getMessage());
          }
       connectionPools.put(name, source);
      }
      return source;
    }


/**
  * 重新绑定数据库连接池
  * @param name  对应连接池的名称
  * @param param 连接池的配置参数，具体请见类ConnectionParam
  * @return DataSource 如果绑定成功后返回连接池对象
  * @throws NameAlreadyBoundException 一定名字name已经绑定则抛出该异常
  * @throws ClassNotFoundException  无法找到连接池的配置中的驱动程序类
  * @throws IllegalAccessException  连接池配置中的驱动程序类有误
  * @throws InstantiationException  无法实例化驱动程序类
  * @throws SQLException    无法正常连接指定的数据库
  */
public static DataSource rebind(String name, ConnectionParam param)
  throws NameAlreadyBoundException,ClassNotFoundException,
    IllegalAccessException,InstantiationException,SQLException,Exception
{
    try{
        unbind(name);
    }catch(Exception e){}
    return bind(name, param);
}

/**
  * 删除一个数据库连接池对象
  * @param name
  * @throws NameNotFoundException
  */
public static void unbind(String name) throws NameNotFoundException
{
  DataSource dataSource = lookup(name);
  if(dataSource instanceof DataSourceImpl){
   DataSourceImpl dsi = (DataSourceImpl)dataSource;
   try{
    dsi.stop();
    dsi.close();
   }catch(Exception e){
   }finally{
    dsi = null;
   }
  }
  connectionPools.remove(name);
}

}