Apache在CentOS上有兩種版本升級方式：
sudo cp -r /etc/httpd /etc/httpd_backup。sudo yum update。sudo yum install httpd。sudo systemctl restart httpd。httpd -v。sudo yum install apr-devel apr-util-devel pcre-devel等。./configure --prefix=/usr/local/apache2等。make && sudo make install。
