ios 聊天demo 和nsoperationdemo
http://blog.csdn.net/zhibudefeng/article/details/7991649
http://blog.csdn.net/kangx6/article/details/7744304
http://blog.csdn.net/zhibudefeng/article/details/7991649
http://blog.csdn.net/kangx6/article/details/7744304