request请求中通过过滤获取准确IP地址

@Service
public class WebserviceFilter  extends HttpServlet implements Filter{

    private static final long serialVersionUID = -4581179717286075213L;

    private IConfigurationInfoService configurationInfoService;

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    /**
     * 过滤请求IP
     * @param ServletRequest
     * @param ServletResponse
     * @param FilterChain
     */
    @Override
    public void doFilter(ServletRequest req, ServletResponse res,
            FilterChain chain) throws IOException, ServletException {

        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) res;
        // 使用x-forwarded-for或Proxy-Client-IP或WL-Proxy-Client-IP得到ip地址
        String ipString = request.getHeader("x-forwarded-for");  
        if (StringUtils.isBlank(ipString) || "unknown".equalsIgnoreCase(ipString)) {  
            ipString = request.getHeader("Proxy-Client-IP");  
        }  
        if (StringUtils.isBlank(ipString) || "unknown".equalsIgnoreCase(ipString)) {  
            ipString = request.getHeader("WL-Proxy-Client-IP");  
        }  
        if (StringUtils.isBlank(ipString) || "unknown".equalsIgnoreCase(ipString)) {  
            // 若以上三种方式均为获取到ip则证明获得客户端并没有采用反向代理直接使用getRemoteAddr()获取客户端的ip地址 
            ipString = request.getRemoteAddr();  
        }


        // 多个路由时，取第一个非unknown的ip
        final String[] arr = ipString.split(",");
        for (final String str : arr) {
            if (!"unknown".equalsIgnoreCase(str)) {
                ipString = str;
                break;
            }
        }

        // 使用WebApplicationUtils获取ConfigurationService
        ServletContext sc = ((HttpServletRequest) req).getSession().getServletContext();
        XmlWebApplicationContext cxt = (XmlWebApplicationContext)WebApplicationContextUtils.getWebApplicationContext(sc);
        if(cxt != null && cxt.getBean("configurationInfoService") != null && configurationInfoService == null){
            configurationInfoService = (IConfigurationInfoService) cxt.getBean("configurationInfoService");
        }

        // 根据分类编号与查询编号获取IP
        String configurationValue = configurationInfoService
                .getConfigurationValueByConFigCode(
                        OperatingIndexConstants.CONFIGURATION_CODE,
                        OperatingIndexConstants.CATEGORY_CODE);

        // 判断是否有匹配的IPAddress,如果有匹配的 放行
        if(StringUtils.isNotBlank(configurationValue) && configurationValue.indexOf(ipString) >= 0){
            chain.doFilter(request, response);
        }
    }
}