运行镜像后，curl http://localhost 为什么拒绝连接
Dockerfile如下：
FROM ubuntu
MAINTAINER xbf
RUN sed -i 's/archive.ubuntu.com/mirrors.ustc.edu.cn/g' /etc/apt/sources.list
RUN apt-get update
RUN apt-get install -y nginx
COPY index.html /var/www/html
ENTRYPOINT ["/usr/sbin/nginx","-g","daemo off;"]
EXPOSE 80
