JDBC值事务

public String transaction(AccountInfo from, AccountInfo to, int account)
    {
        boolean res = false;
        Connection con = DBUtil.getConnection();
        try {
            
            con.setAutoCommit(false);//关闭默认的事务
            from.setAccount(from.getAccount() - account);
            res = update(from);
//            String str = null;
//            str.split("2");
            to.setAccount(to.getAccount() + account);
            res = update(to);
            con.commit(); //提交
            return "success";
        } catch (Exception e) {
            try {
                con.rollback();// 回滚
            } catch (SQLException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
            return "failed";
        }
        
        
        
    }