HttpServletRequest獲取訪問者真實IP

package net.add1s.util;

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;

/**
 * @author lalafaye
 */
public class IpAddressUtils {

    /**
     * 獲取訪問者真實IP地址
     */
    public static String getIpAddr(HttpServletRequest request) {
        String 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();
            if ("127.0.0.1".equals(ipAddress) || "0:0:0:0:0:0:0:1".equals(ipAddress)) {
                // 根據網卡取本機配置的IP
                try {
                    ipAddress = InetAddress.getLocalHost().getHostAddress();
                } catch (UnknownHostException e) {
                    e.printStackTrace();
                }
            }
        }
        // 對於通過多個代理的情況，第一個IP為客戶端真實IP,多個IP按照','分割
        // "***.***.***.***".length()
        if (ipAddress != null && ipAddress.length() > 15) {
            // = 15
            if (ipAddress.indexOf(",") > 0) {
                ipAddress = ipAddress.substring(0, ipAddress.indexOf(","));
            }
        }
        return ipAddress;
    }
}