Nginx在只有一个域名的情况下开启另外一个网站

由于我目前只有一个域名，网站放在/home/www/下，一个网站一个目录，现在想将其中a网站访问形式为，想让另一个与a处于同一目录下的b网站用的形式访问，总结如下：

1.修改/usr/local/etc/apache22/extra/http-vhost.conf

<VirtualHost *:81>
    ServerAdmin webmaster@dummy-host.example.com
    DocumentRoot "/home/www/a"
    ServerName 
  
    ErrorLog "/var/log/www.6688.cc-error_log"
    CustomLog "/var/log/www.6688.cc-access_log" common
  

<Directory "/home/www/a">
      Options none
      AllowOverride none
      Order Allow,deny
      Allow from all
     
   </Directory>

Alias /phpmyadmin/ "/home/www/phpMyAdmin/"
    <Directory "/home/www/phpMyAdmin">
      Options none
      AllowOverride none
      Order Allow,deny
      Allow from all
    </Directory>

Alias /rdya/ "/home/www/b/"
    <Directory "/home/www/b">
      Options none
      AllowOverride none
      Order Allow,deny
      Allow from all
    </Directory>
    
</VirtualHost>

2.修改/usr/local/etc/nginx/nginx.conf

server {
        listen       80;
        server_name  rd.jinchang.gov.cn;

charset gbk;
        client_max_body_size 100m;
        #access_log  logs/host.access.log  main;

location / {
            root   /home/www/a;
            index  index.php index.html index.htm;
        }

#error_page  404              /404.html;

# redirect server error pages to the static page /50x.html
        #
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   /usr/local/www/nginx-dist;
        }

# proxy the PHP scripts to Apache listening on 127.0.0.1:80
        #
        #location ~ \.php$ {
        #    proxy_pass   ;
        #}

# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
        #
        location ~ \.php$ {
        #    root           html;
        #    fastcgi_pass   127.0.0.1:9000;
        #    fastcgi_index  index.php;
        #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
        #    include        fastcgi_params;
           proxy_pass :81;
           proxy_set_header   Host             $host;
           proxy_set_header   X-Real-IP        $remote_addr;
           proxy_set_header   X-Forwarded-For  $proxy_add_x_forwarded_for;
        }

location /b/ {
            alias /home/www/b/;
            index index.php;
        }

# deny access to .htaccess files, if Apache's document root
        # concurs with nginx's one
        #
        location ~ /\.ht {
            deny  all;
        }
    }

3.重启apache，nginx