HttpServletResponse res = (HttpServletResponse) response;
res.setHeader("Access-Control-Allow-Origin", "*");
res.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE, PUT");
res.setHeader("Access-Control-Max-Age", "3600");
res.setHeader("Access-Control-Allow-Headers", "x-requested-with");
chain.doFilter(request, res);
写在filter doFilter中