func getLocalIPv4Address() (ipv4Address string, err error){
	//获取所有网卡
	addrs, err := net.InterfaceAddrs()

	//遍历
	for _, addr := range addrs {
		//取网络地址的网卡的信息
		ipNet, isIpNet := addr.(*net.IPNet)
		//是网卡并且不是本地环回网卡
		if isIpNet && !ipNet.IP.IsLoopback() {
			ipv4 := ipNet.IP.To4()
			//能正常转成ipv4
			if ipv4 != nil {
				return ipv4.String(), nil
			}
		}
	}

	return
}