We have implemented rabbitmq chat in android. but java client of rabbitmq is power hungry.is rabbitmq good for android chat?. we have used direct exchange individual queue for persons and individual routing keys. what is the best design pattern for one to one chat in rabbitmq.
and also ways to reduce battery usage
I don't think that use RabbitMQ directly for developing a chat is the better solution.
There are other solution more light please read this post about MQTT.
Another standard solution is use XMPP protocol (for example whatsup uses a custom XMPP).
We made some test and we also had some problem about battery consuming.
BTW, you can mix the technologies, mixing RabbitMQ as back-end and some other server (XMPP,MQTT) as front-end.
Read this post about the MQTT.
MQTT used by Facebook Messenger
I would add this post MQTT vs. XMPP Which Should I Choose?