後端跨域CorsFilter工具類

@WebFilter(urlPatterns = {"/*"})
@Component
public class CorsFilter implements Filter {
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        HttpServletRequest request = (HttpServletRequest) req;

        String origin = request.getHeader("Origin");
        if (origin == null) {
            origin = request.getHeader("Referer");
        }

        response.setHeader("Access-Control-Allow-Origin", origin);            // 允許指定域訪問跨域資源
        response.setHeader("Access-Control-Allow-Credentials", "true");       // 允許客戶端攜帶跨域cookie，此時origin值不能爲“*”，只能爲指定單一域名
        response.setHeader("Access-Control-Max-Age", "3600");            // 瀏覽器緩存預檢請求結果時間,單位:秒
        response.setHeader("Access-Control-Expose-Headers", "Content-Type,Content-Disposition,Content-Length");

        String allowMethod = request.getHeader("Access-Control-Request-Method");
        if (null != allowMethod) {
            response.setHeader("Access-Control-Allow-Methods", allowMethod);  // 允許瀏覽器在預檢請求成功之後發送的實際請求方法名
        }

        String allowHeaders = request.getHeader("Access-Control-Request-Headers");
        if (null != allowHeaders) {
            response.setHeader("Access-Control-Allow-Headers", allowHeaders); // 允許瀏覽器發送的請求消息頭
        }

        if (RequestMethod.OPTIONS.toString().equals(request.getMethod())) {
           return;
        }

        chain.doFilter(req, res);
    }

    public void init(FilterConfig filterConfig) {
    }

    public void destroy() {
    }
}