Request GetHeader ("X-forwarded-for") Gets the client IP address

In the JSP, the method to obtain the IP address of the client is: Request.getremoteaddr (), which is valid in most cases. However, the real IP address of the client cannot be obtained through the reverse proxy software such as Apache,nagix. If the reverse proxy software is used, the IP address obtained with the REQUEST.GETREMOTEADDR () method is: 127.0.0.1 or 192.168.1.110, not the real IP of the client.

After the agent, due to the addition of the middle tier between the client and the service, so the server can not directly get the client's IP, the server-side application can not directly forward the requested address to the client. However, the x-forwarded-for information is added to the HTTP header information of the forwarding request. Used to track the original client IP address and the server address of the original client request.

public class Getipaddr {

    private static getipaddr instance = new Getipaddr ();

    Private Getipaddr () {
    } public

    static Getipaddr getinstance () {
        return instance;
    }

    Public String getipaddr (HttpServletRequest request) {
        string ip = Request.getheader ("x-forwarded-for");
        if (IP = = NULL | | ip.length () = = 0 | | "Unknown". Equalsignorecase (IP)) {
            IP = request.getheader ("Proxy-client-ip");
        }
        if (IP = = NULL | | ip.length () = = 0 | | "Unknown". Equalsignorecase (IP)) {
            IP = request.getheader ("Wl-proxy-client-ip");
        }
        if (IP = = NULL | | ip.length () = = 0 | | "Unknown". Equalsignorecase (IP)) {
            IP = request.getremoteaddr ();
        }
        return IP;
    }
}