我试图添加一个CORS过滤器到Jetty服务器（使用Jetty 11.0.14），以允许从其他域使用头，但我得到了一些错误。
当我提出请求时

from origin 'null' has been blocked by CORS policy: The 'Access-Control-Allow-Origin' header contains multiple values 'null, *', but only one is allowed.

我有一个简单的Jetty服务器进行测试，以重现我的问题

import org.eclipse.jetty.util.thread.*;
import org.eclipse.jetty.server.*;
import org.eclipse.jetty.servlet.*;
import org.eclipse.jetty.servlets.*;
import jakarta.servlet.*;
import jakarta.servlet.http.*;
import java.io.*;

public class WebServerUtil {
    public static void main(String[] args) {
        try {
            // setup server
            QueuedThreadPool threadPool = new QueuedThreadPool();
            threadPool.setName("server");
            Server server = new Server(threadPool);

            // setup server connections
            HttpConfiguration config = new HttpConfiguration();
            HttpConnectionFactory httpConnection = new HttpConnectionFactory(config);
            ServerConnector connector = new ServerConnector(server, httpConnection);
            connector.setHost("0.0.0.0");
            connector.setPort(8080);
            server.setConnectors(new Connector[] { connector });

            // setup handler
            ServletHandler handler = new ServletHandler();
            server.setHandler(handler);

            // setup cors
            FilterHolder filter = new FilterHolder(CrossOriginFilter.class);
            filter.setName("CORS");
            filter.setInitParameter(CrossOriginFilter.ALLOWED_ORIGINS_PARAM, "*");
            filter.setInitParameter(CrossOriginFilter.ALLOWED_HEADERS_PARAM, "*");
            filter.setInitParameter(CrossOriginFilter.ALLOWED_METHODS_PARAM, "POST, GET, OPTIONS");
            FilterMapping mapping = new FilterMapping();
            mapping.setFilterName("CORS");
            mapping.setPathSpecs(new String[] {"/*"});
            mapping.setDispatches(FilterMapping.ALL);
            handler.addFilter(filter, mapping);

            // basic route
            ServletHolder nothing = new ServletHolder(new Nothing());
            handler.addServletWithMapping(nothing, "/");

            // start server
            server.start();
            server.join();
        } catch(Exception error) {
            System.out.println(error.getMessage());
        }
    }
}

class Nothing extends HttpServlet {
    private static final long serialVersionUID = 1L;
    protected void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
        res.setStatus(200);
        res.addHeader("Access-Control-Allow-Origin", "*");
        res.addHeader("Access-Control-Allow-Headers", "*");
        res.addHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS");
        res.addHeader("Content-Type", "application/json");
        res.getWriter().println("{\"message\":\"Nothing\"}");
    }
}

如果我删除设置cors位下的handler.addFilter(filter, mapping);行，它可以工作，但只有在发出没有标题的请求时才能工作。