JSP如何使用request获取当前访问者的真实IP呢？

当使用反向代理后，我们<%=request.getRemoteAddr() %>,会返回127.0.0.1
那么如何获取访问者的IP信息呢？下文将一一道来，如下所示：

实现思路:
    借助以下方法即可获取访问者的真实IP

 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;       
}