请教：多线程连接数据库，如何传递connection问题(200分)

package com.beaconsystem.relation;
import java.sql.*;
/**
 * Insert the type's description here.
 * Creation date: (7/19/2001 6:24:43 PM)
 * @author: Xiaogang cao
 */
public abstract class AbstractShareConnectionObject {
	protected boolean isNewConnection = false;
	protected java.sql.Connection innerCon = null;
/**
 * ShareConnetionObject constructor comment.
 */
public AbstractShareConnectionObject() {
	super();
}
/**
 * ShareConnetionObject constructor comment.
 */
public AbstractShareConnectionObject(Connection con) 
{
	super();
	this.setCon(con);
}
/**
 * Insert the method's description here.
 * Creation date: (7/6/2001 6:44:04 PM)
 * @return com.beaconsystem.util.db.BeaconConnection
 */
protected void closeCon()
throws SQLException
{
	if (innerCon!=null &&
isNewConnection() == true)
	{
		innerCon.close();
		innerCon = null;
	}
}
/**
 * Insert the method's description here.
 * Creation date: (7/6/2001 6:44:04 PM)
 * @return com.beaconsystem.util.db.BeaconConnection
 */
protected void commit()
throws SQLException
{
	if (innerCon!=null &&
isNewConnection() == true)
	{
		innerCon.commit();
	}
}
/**
 * Insert the method's description here.
 * Creation date: (7/6/2001 6:44:04 PM)
 * @return com.beaconsystem.util.db.BeaconConnection
 */
protected abstract Connection getCon() throws SQLException ;
/**
 * Insert the method's description here.
 * Creation date: (7/6/2001 6:44:22 PM)
 * @return boolean
 */
protected boolean isInTransaction()
throws SQLException
{
	return !this.getCon().getAutoCommit();
}
/**
 * Insert the method's description here.
 * Creation date: (7/13/2001 1:57:21 PM)
 * @return boolean
 */
public boolean isNewConnection() {
	return isNewConnection;
}
/**
 * Insert the method's description here.
 * Creation date: (7/6/2001 6:44:04 PM)
 * @return com.beaconsystem.util.db.BeaconConnection
 */
protected void rollback()
throws SQLException
{
	if (innerCon!=null &&
isNewConnection() == true)
	{
		innerCon.rollback();
	}
}
/**
 * Insert the method's description here.
 * Creation date: (7/6/2001 6:44:04 PM)
 * @param newCon com.beaconsystem.util.db.BeaconConnection
 */
protected void setCon(Connection newCon) 
{
	if (innerCon!=null)
	{
		try
		{
			closeCon();
		}
		catch (Exception e)
		{}
	}
	
	innerCon = newCon;
	setIsNewConnection(false);
	
}
/**
 * Insert the method's description here.
 * Creation date: (7/13/2001 1:57:21 PM)
 * @param newIsNewConnection boolean
 */
public void setIsNewConnection(boolean newIsNewConnection) {
	isNewConnection = newIsNewConnection;
}
}

	java.sql.Connection con = null;
	java.sql.PreparedStatement pstmt = null;
	String SQL = null;
	
	SQL="UPDATE xxxTable set xxx=?";
	try {
		con = getCon();
		int id=1;
		pstmt = con.prepareStatement(SQL);
		pstmt.setString(id++, yyy);
		pstmt.executeUpdate();
		commit();
		//todo
	}
	catch (SQLException sqle) {
		//todo
		rollback();
		System.err.println("Error : " + sqle);
		sqle.printStackTrace();
		throw sqle;
	}
	finally {
		try {pstmt.close();} catch (Exception e) {}
		try {closeCon();
}	catch (Exception e) {}
	}