Detailed explanation of using Nginx to implement 301 redirection

    server {
        listen       80;
        server_name  localhost;
	server_name_in_redirect off;
	proxy_set_header Host $host:$server_port;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header REMOTE-HOST $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
	if ($host = 'www.xxx.com' ) {
	    rewrite ^/(.*)$ http://xxx.com/$1 permanent;
        }
	location / {
	    proxy_pass http://127.0.0.1:8080/;
        }
    }