判断客户真实ip

import javax.servlet.http.HttpServletRequest;

public class IPUtil {
	public static String getIpAddress(HttpServletRequest request) {
		String ipAddress = null;
		ipAddress = request.getRemoteAddr();
		ipAddress = request.getHeader("x-forwarded-for");
		if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
			ipAddress = request.getHeader("Proxy-Client-IP");
		}
		if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
			ipAddress = request.getHeader("WL-Proxy-Client-IP");
		}
		if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
			ipAddress = request.getRemoteAddr();
		}

		// 对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割
		if (ipAddress != null && ipAddress.length() > 15) { // "***.***.***.***".length() = 15
			if (ipAddress.indexOf(",") > 0) {
				ipAddress = ipAddress.substring(0, ipAddress.indexOf(","));
			}
		}
		return ipAddress;
	}
}