nginx 301自动跳转到www的方法

将不带www的域名kunkkawu.com重定向到带www的域名www.kunkkawu.com上很简单：

server {
    listen      80;
    listen      443 ssl;
    server_name kunkkawu.com www.kunkkawu.com;

    if ($host != 'www.kunkkawu.com') {
        return 301 https://www.kunkkawu.com$request_uri;
    }

}

或者：

server {
    listen      80;
    listen      443 ssl;
    server_name kunkkawu.com www.kunkkawu.com;

    if ($host != 'www.kunkkawu.com') {
        rewrite ^(.*) https://www.kunkkawu.com$1 permanent;
    }

}