Java跨域过滤器

 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);
    }