如何获取真实的终端IP

在有Apache做负载均衡的时候使用request.getRemoteAddr();获取的是Apache的IP
，可以通过如下方式获取，先记下来做个备忘。
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();
    }