如何使用Java开发的Web应用程序从http请求中检索源系统的ip地址？

Question

i'm trying to retrieve ip address from HttpServletRequest object using .
Few of my systems are connected in lan with different ip address. i'm able to host my web app in one system and access the web app in other system's. i tried using below code to retrieve the IP address from the http request header by triggering url from browser from different systems.
but i can see only the value 127.0.0.1 or localhost:8080

request.getHeader("X-FORWARDED-FOR");  // returns null
request.getRemoteAddr(); // returns 127.0.0.1

Enumeration headerNames = request.getHeaderNames();
    while (headerNames.hasMoreElements()) {
        String key = (String) headerNames.nextElement();
        String value = request.getHeader(key);
        logger.info("1key: "+key+" 1value: "+value);
    }
//(along with other values, i get) ip value as localhost:8080 

i think the ip shown by the above code, is the ip of the system where the app is launched.

Lets say there are 5 systems
system 1 - ip: 172.22.16.1 (HOST system)
system 2 - ip: 172.22.16.2
system 3 - ip: 172.22.16.3
system 4 - ip: 172.22.16.4
system 5 - ip: 172.22.16.5

when i access the web app from system 5, i need to capture the ip address of system 5 which is 172.22.16.5. But in my case i get only 127.0.0.1

Please let me know what is the problem here and why i'm not able to see the IP address from which request is originating and what should i do to get the output i require.

Though i didnot solve my underlying problem, i was able to figure out what was causing the problem (browse through comments). The discussion helped

Answer 1

If your final goal is to restrict the access of your application only to a given network, then you should achieve this by server and network configuration. One such example is to configure an apache HTTPD server with a virtual host, restricting access only to a given network:

http://www.cyberciti.biz/faq/apache-restrict-access-based-on-ip-address-to-selected-directories/

Open your httpd.conf file:

vi /etc/httpd/conf/httpd.conf Locate directory section (for example/var/www/sub/payroll) and set it as follows:

Order allow,deny Allow from 192.168.1.0/24 Allow from 127

Alternatively you can configure your tomcat to server only on your "local" IP, since I presume you are on a NAT and your server's IP is something like 192.168.1.11.

How do you configure tomcat to bind to a single ip address (localhost) instead of all addresses?

Also, your application should be by default only visible to your local network and you should normally do some extra configuration and routing to make it visible for the outside users.

Answer 2

一种解决方案是将HttpServletRequest请求添加到您的方法，然后按如下所示使用Servlet API：

System.out.println(request.getRemoteAddr());