嵌入式Jetty如何加载第二个Servlet之前能获得第一个Servlet的参数

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嵌入式Jetty如何加载第二个Servlet之前能获得第一个Servlet的参数0

因为本人用嵌入式开发Web，所以没有配置web.xml，用main方法启动服务加载配置，但是因为用到cometd长连接，就出现的问题

如果是web.xml配置如下

<!-- Cometd配置 -->
	<servlet>
        <servlet-name>cometd</servlet-name>
        <servlet-class>org.cometd.server.CometdServlet</servlet-class>         
        <init-param>
			<param-name>jsonContext</param-name>
			<param-value>
				org.cometd.server.JettyJSONContextServer
			</param-value>
		</init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>cometd</servlet-name>
        <url-pattern>/cometd/*</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>initializer</servlet-name>
        <servlet-class>com.yixun.collector.controller.BayeuxInitializer</servlet-class>
        <load-on-startup>2</load-on-startup>
    </servlet>

但是我在JettyWebServer类中配置就出现了问题

public class JettyWebServer {
	public static void main(String[] args) throws Exception {
		Server server = new Server();// 创建服务
		server.setStopAtShutdown(true);// 在退出程序是关闭服务

		Connector connector = new SelectChannelConnector();// 创建一个连接
		connector.setPort(8080);// 连接的端口号一般是8080，这里根据服务需求进行设置
		connector.setHost("localhost");// ip地址
		server.addConnector(connector);// 添加连接

		ServletContextHandler context = new ServletContextHandler(server,
				"/collector", ServletContextHandler.SESSIONS);
		ContextLoaderListener listener = new ContextLoaderListener();
		context.setResourceBase("Webapp");
		context.addEventListener(listener);
		
		holder = new ServletHolder(new CometdServlet());
        holder.setInitParameter("jsonContext","org.cometd.server.Jetty                JSONContextServer");
		context.addServlet(holder, "/cometd/*");
		//加载BayeuxInitializer需要CometdServlet的参数，下面        //的BayeuxInitializer有写到,请问应该如何配置，才不会报空指针异常
		BayeuxInitializer bayeuxInitializer=new BayeuxInitializer();
		holder=new ServletHolder(bayeuxInitializer);
		context.addServlet(holder, "");

		server.setHandler(context);		
		server.start();
		server.join();
	}
}

BayeuxInitializer类的代码：

public class BayeuxInitializer extends GenericServlet
{
	private static final long serialVersionUID = 7280618021210587163L;

	public void init() throws ServletException
    {
        BayeuxServer bayeux = (BayeuxServer)getServletContext().getAttribute(BayeuxServer.ATTRIBUTE);       //按如上JettyWebServer配置，下面的一行会报空指针
          //就是说bayeux没有获得
        new HelloService(bayeux); //初始化服务类，与Servlet 关联上
    }

    public void service(ServletRequest request, ServletResponse response) throws ServletException, IOException
    {
        throw new ServletException();
    }
    
}

异常信息如下：

java.lang.NullPointerException: null
	at org.cometd.server.AbstractService.<init>(AbstractService.java:94) ~[cometd-java-server-2.5.0-beta2.jar:na]
	at org.cometd.server.AbstractService.<init>(AbstractService.java:80) ~[cometd-java-server-2.5.0-beta2.jar:na]
	at com.yixun.collector.controller.HelloService.<init>(HelloService.java:16) ~[classes/:na]
	at com.yixun.collector.controller.BayeuxInitializer.init(BayeuxInitializer.java:34) ~[classes/:na]
	at javax.servlet.GenericServlet.init(GenericServlet.java:244) ~[javax.servlet-3.0.0.v201112011016.jar:na]
	at org.eclipse.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:492) [jetty-all-8.1.4.v20120524.jar:8.1.4.v20120524]
	at org.eclipse.jetty.servlet.ServletHolder.doStart(ServletHolder.java:312) [jetty-all-8.1.4.v20120524.jar:8.1.4.v20120524]
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59) [jetty-util-7.6.4.v20120524.jar:7.6.4.v20120524]
	at org.eclipse.jetty.servlet.ServletHandler.initialize(ServletHandler.java:778) [jetty-all-8.1.4.v20120524.jar:8.1.4.v20120524]
	at org.eclipse.jetty.servlet.ServletContextHandler.startContext(ServletContextHandler.java:258) [jetty-all-8.1.4.v20120524.jar:8.1.4.v20120524]
	at org.eclipse.jetty.server.handler.ContextHandler.doStart(ContextHandler.java:699) [jetty-all-8.1.4.v20120524.jar:8.1.4.v20120524]
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59) [jetty-util-7.6.4.v20120524.jar:7.6.4.v20120524]
	at org.eclipse.jetty.server.handler.HandlerCollection.doStart(HandlerCollection.java:224) [jetty-all-8.1.4.v20120524.jar:8.1.4.v20120524]
	at org.eclipse.jetty.server.handler.ContextHandlerCollection.doStart(ContextHandlerCollection.java:167) [jetty-all-8.1.4.v20120524.jar:8.1.4.v20120524]
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59) [jetty-util-7.6.4.v20120524.jar:7.6.4.v20120524]
	at org.eclipse.jetty.server.handler.HandlerWrapper.doStart(HandlerWrapper.java:90) [jetty-all-8.1.4.v20120524.jar:8.1.4.v20120524]
	at org.eclipse.jetty.server.Server.doStart(Server.java:262) [jetty-all-8.1.4.v20120524.jar:8.1.4.v20120524]
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:59) [jetty-util-7.6.4.v20120524.jar:7.6.4.v20120524]
	at com.yixun.collector.jetty.JettyWebServer.main(JettyWebServer.java:91) [classes/:na]

问题补充：再补充一下，
去掉
BayeuxInitializer bayeuxInitializer=new BayeuxInitializer();
holder=new ServletHolder(bayeuxInitializer);
context.addServlet(holder, ""); 可以连接上，但是没有数据推送到前台