request获取客户端IP地址

public String getIpAddr(HttpServletRequest request) { 
//X-Forwarded-For:简称XFF头，它代表客户端，也就是HTTP的请求端真实的IP，只有在通过了HTTP 代理或者负载均衡服务器时才会添加该项

 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();  

 }  

 if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {  

  ip = request.getHeader("http_client_ip");  

 }  

 if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {  

  ip = request.getHeader("HTTP_X_FORWARDED_FOR");  

 }  

 // 如果是多级代理，那么取第一个ip为客户ip  

 if (ip != null && ip.indexOf(",") != -1) {  

  ip = ip.substring(ip.lastIndexOf(",") + 1, ip.length()).trim();  

 }  

 return ip;  

}