复习

为解决业务代码和数据访问代码的紧藕合给修改和维护代码带来

                            的不便，推荐使用DAO模式封装JDBC

 

                                                                DAO接口

                                                                DAO实现类

                                DAC模式组成部分：实体类

                                                                 数据库连接和关闭工具类

        

       

                                 DAO模式的优势：         隔离了数据访问代码和业务逻辑代码

DAO模式                                                         隔离了不同数据库实现

 

 

                                                                                                   优势：能够脱离程序本身去修改相关的变量设置

                                使用Properties类读取配置文件：              Properties配置文件：由键-值对组成

                                                                                                   读取配置文件：使用Properties类相应方法