upstream 127.0.0.1 {
 server 127.0.0.1:8080;
    }

    server {
        listen       80;
        server_name  127.0.0.1;

        #charset koi8-r;

        #access_log  logs/host.access.log  main;

        location / {
     proxy_passhttp://127.0.0.1;
     proxy_set_header  X-Real-IP  $remote_addr;  ///这里设置
            root   html;
            index  index.html index.htm;
        }

第二步：应用程序中用 String ip = request.getHeader("X-Real-IP");替代String ip = request.getRemoteAddr();