Android uploads pictures to the server okhttp one

（1） Upload pictures to server I ------------------------------- Android code

（2） Upload pictures to server 2 -------------------------------- compatibility problem of calling camera above Android system 7.0

（3） Upload pictures to server 3 -------------------------------------- background server code

① Android permission application

② Network access framework okhttp

③ Memory overflow problem: picture compression

④ Calling system camera above Android system 7.0 is invalid

⑤ About the memory overflow problem encountered during picture upload

< basic functions >

Entity class

Note: a proveder needs to be configured in Android. For details, please refer to the compatibility of calling cameras above Android system 7.0