java - jetty WebSocket

Question

我对 jetty 8.1.10.v20130312 和 WebSocket 有疑问。这是代码:

web.xml

<listener>
    <listener-class>ru.websocket.StartupListener</listener-class>
</listener>

StartupListener.java

public class StartupListener implements ServletContextListener {

public void contextDestroyed(ServletContextEvent arg0) {

}

public void contextInitialized(ServletContextEvent arg0) {
    Server server = new Server(8081);
    EventHandler handler = new EventHandler();
    server.setHandler(handler);
    try {
        server.start();
        System.out.println("Server started");
    } catch (Exception e) {
        e.printStackTrace();
    }
}

}

EventHandler.java

public class EventHandler extends WebSocketHandler {

public WebSocket doWebSocketConnect(HttpServletRequest arg0, String arg1) {
     return new EventWebSocket();
}

}

EventWebSocket.java

public class EventWebSocket implements WebSocket {

public void onClose(int arg0, String arg1) {
    System.out.println("closed");
}

public void onOpen(Connection arg0) {
    System.out.println("opened");
}

}

当我想从 javascript 连接时，出现错误消息

2013-07-15 18:02:02.433:WARN:oejs.AbstractHttpConnection:/
java.lang.NullPointerException
        at org.eclipse.jetty.websocket.WebSocketFactory.upgrade(WebSocketFactory.java:238)
        at org.eclipse.jetty.websocket.WebSocketFactory.acceptWebSocket(WebSocketFactory.java:396)
        at org.eclipse.jetty.websocket.WebSocketHandler.handle(WebSocketHandler.java:43)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
        at org.eclipse.jetty.server.Server.handle(Server.java:368)
        at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:489)
        at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:942)
        at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:1004)
        at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:640)
        at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:235)
        at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
        at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:628)
        at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52)
        at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
        at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
        at java.lang.Thread.run(Thread.java:662)

关于构建，我使用maven，java版本1.6.31，jetty版本8.1.10.v20130312。重要我想从端口 8080 (StartupListener) 上的 Jetty 使用端口 8081 启动新的 Jetty 服务器。

感谢您的回答。

Answer 1

org.eclipse.jetty.websocket.WebSocketFactory.upgrade(WebSocketFactory.java:238) 处的 java.lang.NullPointerException 意味着您要么...

• 尝试使用来自非 Jetty 服务器(例如 Tomcat)的 Jetty WebSocket 代码。
• 或者您尝试从非 HTTP 连接(例如 SPDY)升级。

这是因为在 WebSocket 握手的升级过程中无法找到核心 HTTP 连接，这是 Jetty WebSocket 服务器代码正常运行的要求。