private FilterConfig config = null;

    @Override

    public void init(FilterConfig config) throws ServletException {

        this.config = config;

    }

    @Override

    public void destroy() {

        this.config = null;

    }

    /**

     *

     * @author wwhhf

     * @since 2016/5/30

     * @comment 跨域的设置

     */

    @Override

    public void doFilter(ServletRequest request, ServletResponse response,

            FilterChain chain) throws IOException, ServletException {

        HttpServletResponse httpResponse = (HttpServletResponse) response;

        // 表明它允许"http://xxx"发起跨域请求

        httpResponse.setHeader("Access-Control-Allow-Origin",

                config.getInitParameter("AccessControlAllowOrigin"));

        // 表明在xxx秒内，不需要再发送预检验请求，可以缓存该结果

        httpResponse.setHeader("Access-Control-Allow-Methods",

                config.getInitParameter("AccessControlAllowMethods"));

        // 表明它允许xxx的外域请求

        httpResponse.setHeader("Access-Control-Max-Age",

                config.getInitParameter("AccessControlMaxAge"));

        // 表明它允许跨域请求包含xxx头

        httpResponse.setHeader("Access-Control-Allow-Headers",

                config.getInitParameter("AccessControlAllowHeaders"));

        chain.doFilter(request, response);

    }