nginx中进行301重定向(301 redirect)是非常容易的。比方说要将www.caipanzi.com永久性重定向至caipanzi.com，有两种方法：

1.方法A

server {
    server_name caipanzi.com www.caipanzi.com;

    if ($host != 'caipanzi.com' ) {
        rewrite  ^/(.*)$  http://caipanzi.com/$1  permanent;
        proxy_set_header Host "caipanzi.com";
    }
    ...
}

2.方法B(为带www的域名单独设一条server规则)

server {
    server_name  www.caipanzi.com;
    rewrite ^(.*) http://caipanzi.com$1 permanent;
}

菜盘子目前用的是第2种方法。