經過Threadlocal來管理事務

public class ConnectionManager
{
   public static final ThreadLocal threadLocal = new ThreadLocal();

  @SuppressWarnings( "unchecked")
   public static Connection getCurrentConnection()
  {
    Connection conn = (Connection) threadLocal.get();
     if (conn == null)
    {
       try
      {
        conn = ConnectionPool.getInstance().getConnection(); // 得到鏈接
        threadLocal.set(conn);
      } catch (DBConnectionException e)
      {
        e.printStackTrace();
      }
    }
     try
    {
       while (conn.isClosed())
      {
        conn = ConnectionPool.getInstance().getConnection();
        threadLocal.set(conn);
      }
    } catch (Exception e)
    {
      e.printStackTrace();
    }
     return conn;
  }

  @SuppressWarnings( "unchecked")
   public static void closeConnection()
  {
    Connection conn = (Connection) threadLocal.get();
    threadLocal.set( null);
     if (conn != null)
    {
       try
      {
        ConnectionPool.getInstance().freeConnection(conn);
      } catch (DBConnectionException e)
      {
        e.printStackTrace();
      }
    }
  }

   public static void rollback()
  {
     try
    {
      ConnectionManager.getCurrentConnection().rollback();
    } catch (SQLException e)
    {
      e.printStackTrace();
    }
  }

   public static void commit()
  {
     try
    {
      ConnectionManager.getCurrentConnection().commit();
    } catch (SQLException e)
    {
      e.printStackTrace();
    }
  }

   public static void setAutoCommit( boolean bool)
  {
     try
    {
      ConnectionManager.getCurrentConnection().setAutoCommit(bool);
    } catch (SQLException e)     {       e.printStackTrace();     }   } }