nginx 将无www转换为有www失败，为什么？

nginx 将无www转换为有www失败，为什么？

server {
        listen       80;
        server_name  www.testsite.com;
        index index.html index.htm index.php;
        root /alidata/www/testsite;
        location ~ .*\.(php|php5)?$
        {
                #fastcgi_pass  unix:/tmp/php-cgi.sock;
                fastcgi_pass  127.0.0.1:9000;
                fastcgi_index index.php;
                include fastcgi.conf;
        }
        location ~ .*\.(gif|jpg|jpeg|png|bmp|swf)$
        {
                expires 30d;
        }
        location ~ .*\.(js|css)?$
        {
                expires 1h;
        }
        #α¾²Ì¬¹æÔò
        include /alidata/server/nginx/conf/rewrite/phpwind.conf;
        access_log  /alidata/log/nginx/access/http.log;
}
server {
        server_name  testsite.com;
        return 301 http://www.testsite.com$request_uri;
}

带www,访问成功，不带访问失败，浏览器提示
414 Request-URI Too Large
发现浏览器实际地址为
http://testsite.com/www.testsite.com/www.testsite.com/.....(不断重复)
应该怎么解决

server {
listen 80;
server_name testsite.com;
rewrite ^/(.*) http://www.testsite.com/$1 permanent;
}

server {
listen 80;
server_name 127.0.0.1;

 server {
        listen       80;
        server_name www.testsite.com;
        location / {
            root   html;
            index  index.html index.htm;
                     proxy_pass   http://127.0.0.1:服务端口号;
        }
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;

        }

    }

    我推荐你用上面这个配置，至于www访问问题，你需要到域名控制台去进行域名解析，加入一个@解析，也称为泛解析，之后就额可以正常访问。 

server {
listen 80;
server_name testsite.com;
location / {
proxy_pass www.testsite.com;
}
}

试试这个吧，改完了记得nginx -s reload