Simple code for a Java servlet to get information about the client

Java web very common functional code, you can achieve IP whitelist control, directly paste code:

import javax.servlet.http.HttpServletRequest;
public class ClientInfoUtil{

static public String getIP(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;
}


static public String getURL(HttpServletRequest request) {
    String url = request.getScheme()+"://";   
    url+=request.getHeader("host");   
    url+=request.getRequestURI();   
    if(request.getQueryString()!=null)  {
        url+="?"+request.getQueryString();   
    }
    return url;
}
}