server {          listen 80;        server_name www.espressos.com;        location / {                  root /data0/www/bbs;                index index.html index.htm;                fastcgi_intercept_errors on;                error_page 404 http://espressos.com;                access_log /app/logs/bbs_access.log commonlog;         }   }#当出现404错误时,会跳转到指定的URL http://espressos.com