jdbc封装类连接数据库的方法
http://blog.leanote.com/post/gavin176/Java%E9%80%9A%E8%BF%87JDBC%E8%BF%9E%E6%8E%A5MySQL%E6%95%B0%E6%8D%AE%E5%BA%93
http://blog.leanote.com/post/gavin176/Java%E9%80%9A%E8%BF%87JDBC%E8%BF%9E%E6%8E%A5MySQL%E6%95%B0%E6%8D%AE%E5%BA%93
