session跨域问题怎么解决？这是我写的代码~~请各位给掌掌眼

Question

public class CookieUtil implements Filter {

    private Logger logger  = LoggerFactory.getLogger(CookieUtil.class);

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        logger.info("======初始化,允许跨域请求=========");
    }

    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
            throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) res;

        response.setContentType("textml;charset=UTF-8");
        response.setHeader("Access-Control-Allow-Origin", request.getHeader("Origin"));
        response.setHeader("Access-Control-Allow-Credentials", "true");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "X-Requested-With,Origin, No-Cache, X-Requested-With, If-Modified-Since, Pragma, Last-Modified, Cache-Control, Expires, Content-Type, X-E4M-With,userId,token");
        response.setHeader("XDomainRequestAllowed","3600");

        chain.doFilter(req, res);   

   @Override
    public void destroy() {
    }
}

web.xml中添加
<filter>
        <filter-name>CookieUtil</filter-name>
        <filter-class>com.oa.ml.util.CookieUtil</filter-class>
</filter> 
    <filter-mapping>
        <filter-name>CookieUtil</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

js中添加：
xhrFields: {
withCredentials: true
},
dataType:'JSON'

为什么session还是丢失？

Answer 1

在前端的框架要开启session