解决react-native 8081端口占用问题

解决思路：既然端口被占用了那么就看被那个进程占用了，然后kill调那个进程即可！
Mac OS 环境

#查看某个端口是否占用比如8081：
lsof -i:8081
#显示如下信息：
COMMAND     PID    USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
node      26266 hehuiqi   20u  IPv6 0xdb980f4c9bbe8dd3      0t0  TCP *:sunproxyadmin (LISTEN)
node      26266 hehuiqi   33u  IPv6 0xdb980f4c9bbe5fd3      0t0  TCP localhost:sunproxyadmin->localhost:56349 (ESTABLISHED)
HelloWord 26273 hehuiqi   10u  IPv4 0xdb980f4c88f21f9b      0t0  TCP localhost:56349->localhost:sunproxyadmin (ESTABLISHED)
HelloWord 26273 hehuiqi   12u  IPv4 0xdb980f4c88f21f9b      0t0  TCP localhost:56349->localhost:sunproxyadmin (ESTABLISHED)
# COMMAND:进程名 PID:进程ID
#找到了占用端口的进程，那就kill它就可以了 kill PID
kill 26266 26273
#重新运行项目即可