获取远程用户IP

public class WebUtil {
	
	/**
	 * 获取远程用户IP
	 * @param request
	 * @return
	 */
	public static String getIp(HttpServletRequest request){
		String ip = request.getRemoteAddr();
		if(ip == null || ip.trim().length() == 0 || "unknown".equalsIgnoreCase(ip)){
			ip = request.getHeader("x-forwarded-for");
		}
		if(ip == null || ip.trim().length() == 0 || "unknown".equalsIgnoreCase(ip)) {
			ip = request.getHeader("Proxy-Client-IP");
		}
		if(ip == null || ip.trim().length() == 0 || "unknown".equalsIgnoreCase(ip)) {
			ip = request.getHeader("WL-Proxy-Client-IP");
		}
		if(ip == null || ip.trim().length() == 0 || "unknown".equalsIgnoreCase(ip)) {
			ip = request.getHeader("X-Real-IP");
		}
		return ip;
	}
}