问题：Appium执行，连接手机报下面的错误
Error: Android bootstrap socket crashed: Error: getaddrinfo ENOTFOUND localhost undefined:4724
at Socket.<anonymous> (lib/bootstrap.js:87:21)
at emitOne (events.js:90:13)
at Socket.emit (events.js:182:7)
at connectErrorNT (net.js:994:8)
at _combinedTickCallback (internal/process/next_tick.js:74:11)
at process._tickCallback (internal/process/next_tick.js:98:9)
解决方法：
在hosts文件中增加【127.0.0.1 localhost】
（mac和linux中hosts文件目录：/etc/hosts）