java获取客户端IP地址

public String getIpAddr() { 
HttpServletRequest request= this.getRequest();
 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; }