启动类中添加：

@ServletComponentScan(basePackages = {"com.crazyape.leave.filter"})

添加工具类 filter包SimpleCORSFilter:

@WebFilter(filterName = "authFilter", urlPatterns = "/*")
@Order(1) //测试好像这个参数不生效，实际生效的是Filter扫描到的顺序（所以起名很重要）
public class SimpleCORSFilter implements Filter {


    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        System.out.println("--------dofilter------------");
        HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) res;
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE, PUT, GET");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "x-requested-with");
        System.out.println("============dofilter========");
        chain.doFilter(req, res);
    }
    @Override
    public void init(FilterConfig filterConfig) {}

    @Override
    public void destroy() {}
}