从Java 1.7 以后NIO可以采用系统底层的Socket来实现了，大大提高了吞吐量。

相比Reactor方式，Nio2可以称为Proactor方式的实现。具体是程序避免等待而采用回调函数类。-From Java 1.7 after NIO Socket can be used to achieve the underlying system, and greatly improving the throughput. Compared to Reactor way, Nio2 may be referred to achieve Proactor mode. Specifically procedures to avoid waiting while using a callback function class.