如何从android中的USB笔式驱动器读取/写入文件

Question

我创建了一个拥有数据库的应用程序。我想复制，更新数据库，读取和写入USB Pen Drive数据库。我不知道如何检测以下内容。

1) How to check android phone support OTG(Pen drive support) from application itself without using any 3rd party Application. 
2) Check USB pen drive is connected to Android Phone or not.
3) Read the File if it is already exist on Pen drive.(without using any 3rd party Application)
4) Write the File to Pend drive.(without using any 3rd party Application)

我想知道从哪里开始。