Java中根据request请求获取请求端真实的ip地址

为了获取客户端的ip地址，我们常用的做法是利用HttpServletRequest中的request.getRemoteAddr()来获取的，但是由于服务器端由于为了保护安全信息或者为了负载均衡可能采取了apache,squid,nginx等反向代理软件，这时候再采取使用这种方式获取的就不是真实的客户端的ip地址了。

以下上代码

public static final String LOCAL_IP = "127.0.0.1";//本地ip地址
public static final String DEFAULT_IP = "0:0:0:0:0:0:0:1";//默认ip地址
public static final int DEFAULT_IP_LENGTH = 15;//默认ip地址长度

/**
 * 获取合法ip地址
 * @param request
 * @return
 */
public static String getRealIpAddress(HttpServletRequest request) {
    String ip = request.getHeader("x-forwarded-for");//squid 服务代理
    if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
        ip = request.getHeader("Proxy-Client-IP");//apache服务代理
    }
    if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
        ip = request.getHeader("WL-Proxy-Client-IP");//weblogic 代理
    }

    if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
        ip = request.getHeader("HTTP_CLIENT_IP");//有些代理
    }

    if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
        ip = request.getHeader("X-Real-IP"); //nginx代理
    }

    /*
    * 如果此时还是获取不到ip地址，那么最后就使用request.getRemoteAddr()来获取
    * */
    if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
        ip = request.getRemoteAddr();
        if(StringUtils.equals(ip,LOCAL_IP) || StringUtils.equals(ip,DEFAULT_IP)){
            //根据网卡取本机配置的IP
            InetAddress iNet = null;
            try {
                iNet = InetAddress.getLocalHost();
            } catch (UnknownHostException e) {
                logger.error("InetAddress getLocalHost error In HttpUtils getRealIpAddress: " ,e);
            }
            ip= iNet.getHostAddress();
        }
    }
    //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
    //"***.***.***.***".length() = 15
    if(!StringUtils.isEmpty(ip) && ip.length()> DEFAULT_IP_LENGTH){
        if(ip.indexOf(",") > 0){
            ip = ip.substring(0,ip.indexOf(","));
        }
    }
    return ip;
}