发布数据的CometD问题

Question

我是CometD新手，在渠道上发布数据时遇到了问题。我得到了以下错误，因为我没有在我的通道上调用握手()：

Sender : null Sender : L:/abc/1? Exception in thread "Thread-9" java.lang.IllegalStateException: Method handshake() not invoked for local session L:/abc/1? at org.cometd.server.LocalSessionImpl.getId(LocalSessionImpl.java:161) at org.cometd.server.ServerChannelImpl.publish(ServerChannelImpl.java:309) at packagename.CometDSender.sendData(CometDSender.java:64) at packagename.ProcessorImp.processData(ProcessorImp.java:18) at packagename.TestSource.processNewData(TestSource.java:50) at packagename.TestSource.run(TestSource.java:36) at java.lang.Thread.run(Unknown Source)

但是，当我包含sender.handshake()时，我会得到以下异常

    Sender : null
Sender : L:/abc/1?
Exception in thread "Thread-9" java.lang.NullPointerException
    at org.cometd.server.BayeuxServerImpl.freeze(BayeuxServerImpl.java:868)
    at org.cometd.server.BayeuxServerImpl.doPublish(BayeuxServerImpl.java:823)
    at org.cometd.server.BayeuxServerImpl.handle(BayeuxServerImpl.java:649)
    at org.cometd.server.LocalSessionImpl.doSend(LocalSessionImpl.java:214)
    at org.cometd.server.LocalSessionImpl.handshake(LocalSessionImpl.java:125)
    at org.cometd.server.LocalSessionImpl.handshake(LocalSessionImpl.java:110)
    at packagename.CometDSender.sendData(CometDSender.java:62)
    at packagename.ProcessorImp.processData(ProcessorImp.java:18)
    at packagename.TestSource.processNewData(TestSource.java:50)
    at packagename.TestSource.run(TestSource.java:36)
    at java.lang.Thread.run(Unknown Source)

我已经在下面添加了我的类。谁能告诉我我是不是漏掉了什么：

@Service

公共类CometDSender实现了发送者{

@Inject
private BayeuxServer bayeuxServer;

@Session
private LocalSession sender;

private String channelName = null;

// setup CometD Channel
public CometDSender() {

    this.channelName = "/abc/1";

    System.out.println("bayeuxServer : " + (bayeuxServer == null ? "Is Null" : "Is Not Null"));
    if (bayeuxServer == null) {
        bayeuxServer = new BayeuxServerImpl();
    }

    bayeuxServer.createIfAbsent(channelName, new ConfigurableServerChannel.Initializer() {
    public void configureChannel(ConfigurableServerChannel channelName) {
        System.out.println("channel : " + (channelName == null ? "Is Null" : "Is Not Null"));
        channelName.setPersistent(true);
        channelName.setLazy(true);
        }
    });

}

public void sendData(Agent data) {

    // Convert the Update business object to a CometD-friendly format
    Map<String, Object> cometData = new HashMap<String, Object>(4);
    cometData.put("ID", data.getID());      

    // Publish to all subscribers
    ServerChannel channel = bayeuxServer.getChannel(channelName);
    System.out.println("Sender : " + sender);       

    if (sender == null) {
        sender = bayeuxServer.newLocalSession(channelName);
        System.out.println("Sender : " + sender);
        sender.handshake();         
    }   
    channel.publish(sender, cometData, null);

}

}

Answer 1

除非您知道自己在做什么，否则不能创建BayeuxServerImpl实例，LocalSession也是如此。由于您使用的是CometD服务，因此这些字段必须为非空，并且您不能自己创建它们。它们可能是空的，这是因为你的web.xml中很可能有一个错误的配置(你没有发布)。

请阅读有关CometD services的文档并遵循tutorials：它们将指导您一步一步地解决CometD服务问题。