java获取request请求客户端的IP地址

工具类如下：

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;     
}