获取来源IP地址

获得客户端真实IP地址的方法一：

public String getRemortIP(HttpServletRequest request) {
    if (request.getHeader(”x-forwarded-for”) == null) {
        return request.getRemoteAddr();
    }
    return request.getHeader(”x-forwarded-for”);
} 

获得客户端真实IP地址的方法二：

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;
} 

如果通过了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP值，究竟哪个才是真正的用户端的真实IP呢？

答案是取X-Forwarded-For中第一个非unknown的有效IP字符串。如：
X-Forwarded-For：192.168.1.110, 192.168.1.120, 192.168.1.130, 192.168.1.100
用户真实IP为： 192.168.1.110

public String getIp() {
        String forwaredFor = getRequest().getHeader("X-Forwarded-For");
        String remoteAddr = getRequest().getRemoteAddr();
        if (StringUtils.isNotEmpty(forwaredFor)) {
            String[] ipArray = forwaredFor.split(",");
            return ipArray[0];
        } else
            return remoteAddr;
    }