这些套接字流示例期望在启动flink作业之前已启动服务器(netcat)并将其绑定到端口.通常，这是通过

Those socket stream examples expect that a server (netcat) has been started and is bound to the port before the flink job starts. Normally this is done via

nc -lk 9000

但是需要一些版本的netcat

but some versions of netcat need

nc -l -p 9000

请参见 Apache flink(稳定版1.6.2)无效，对此没有更多讨论.

See Apache flink (Stable version 1.6.2) does not work for more discussion of this.