工厂模式的新写法
注释改变
更改连接字符串的检查模式，当连接执行的时候才检查是否为空
Signed-off-by: greatbody <wedown@163.com>
Signed-off-by: greatbody <sunruiyeyipeng@163.com>
Signed-off-by: greatbody <wedown@163.com>
renew DAL layer