Applicable scenarios of java NIO
NIO applicable scenarios
The server needs to support a very large number of long-term connections. Like more than 10,000 connections, and each client doesn't send too much data frequently. For example, a central server in the head office needs to collect transaction information from all cash registers in convenience stores across the country, and only needs a small number of threads to process and maintain a large number of long-term connections on demand.
Jetty, Mina, Netty, ZooKeeper, etc. are all implemented based on NIO.
BIO applicable scenarios
It is suitable for scenarios where the number of connections is relatively small and a large amount of data is sent at one time. This method requires high server resources and concurrency is limited to applications.
http://blog.csdn.net/jiyiqinlovexx/article/details/51204726