Jetty-独立WebSocket服务器

最近我尝试使用Jetty实现WebSocket服务器

我在Jetty 9.2.0.v20140526的发行版中创建了一个名为“WebSocketServer”的Jetty项目，作为

demo base

之后，我编写了一些代码来实现WebSocket机制，并将所有代码导出到

war

文件中，将其推送到“WebSocketServer”的

webapps

文件夹中。当我

java-jar../start.jar

时，一切都是可行的。但是，在我创建到这个WebSocket项目的新连接之后，出现了一些错误代码

java.lang.ClassCastException: org.eclipse.jetty.server.HttpConnection cannot be cast to org.eclipse.jetty.server.HttpConnection
at org.eclipse.jetty.websocket.server.WebSocketServerFactory.acceptWebSocket(WebSocketServerFactory.java:175)
at org.eclipse.jetty.websocket.server.WebSocketServerFactory.acceptWebSocket(WebSocketServerFactory.java:148)
at org.eclipse.jetty.websocket.servlet.WebSocketServlet.service(WebSocketServlet.java:151)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:751)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:566)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:578)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:221)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1111)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:498)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:183)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1045)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:199)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:109)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:98)
at org.eclipse.jetty.server.Server.handle(Server.java:461)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:284)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:244)
at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:534)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:607)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:536)
at java.lang.Thread.run(Thread.java:744)

我不知道发生了什么事？以下代码是我为构建一个简单的WebSocket服务器而编写的

Servlet:

@SuppressWarnings("serial")
public class XYZWebSocketServlet extends WebSocketServlet{
    @Override
    public void configure(WebSocketServletFactory factory) {
        factory.getPolicy().setIdleTimeout(600000);
        factory.register(XYZWebSocketEvent.class);
    }
}

@WebSocket
public class XYZWebSocketEvent {
    private Session session;

    @OnWebSocketConnect
    public void onConnect(Session sess) {
        session = sess;

        // Get parameters while client connect to server
        Map<String,List<String>> parameters = session.getUpgradeRequest().getParameterMap();
        String encyptedID = parameters.get("ID").get(0);

        System.out.println("Connect: " + session.getRemoteAddress().getPort());
        try {
            session.setIdleTimeout(600000);
            session.getRemote().sendString("Hello!");
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
    }

    @OnWebSocketMessage
    public void onMessage(String message) {
            try {   
                session.getRemote().sendString("Message: " + message);
            }
            catch (Exception ex) {
            }
    }

    @OnWebSocketClose
    public void onClose(int statusCode, String reason) {
            try {
                session.getRemote().sendString("Close: statusCode=" + statusCode + ", reason=" +reason);
        }
            catch (Exception ex) {
            }
    }

    @OnWebSocketError
    public void onError(Throwable t) {
        System.out.println("Error: " + t.getMessage());
    }

    public Session getSession() {
        return this.session;
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app>
    <display-name>WebSocket application</display-name>
    <servlet>
        <servlet-name>XYZWebSocketServlet</servlet-name>
        <servlet-class>com.newKinpo.servlet.XYZWebSocketServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>XYZWebSocketServlet</servlet-name>
        <url-pattern>/events/*</url-pattern>
    </servlet-mapping>
</web-app>

事件：

@SuppressWarnings("serial")
public class XYZWebSocketServlet extends WebSocketServlet{
    @Override
    public void configure(WebSocketServletFactory factory) {
        factory.getPolicy().setIdleTimeout(600000);
        factory.register(XYZWebSocketEvent.class);
    }
}

@WebSocket
public class XYZWebSocketEvent {
    private Session session;

    @OnWebSocketConnect
    public void onConnect(Session sess) {
        session = sess;

        // Get parameters while client connect to server
        Map<String,List<String>> parameters = session.getUpgradeRequest().getParameterMap();
        String encyptedID = parameters.get("ID").get(0);

        System.out.println("Connect: " + session.getRemoteAddress().getPort());
        try {
            session.setIdleTimeout(600000);
            session.getRemote().sendString("Hello!");
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
    }

    @OnWebSocketMessage
    public void onMessage(String message) {
            try {   
                session.getRemote().sendString("Message: " + message);
            }
            catch (Exception ex) {
            }
    }

    @OnWebSocketClose
    public void onClose(int statusCode, String reason) {
            try {
                session.getRemote().sendString("Close: statusCode=" + statusCode + ", reason=" +reason);
        }
            catch (Exception ex) {
            }
    }

    @OnWebSocketError
    public void onError(Throwable t) {
        System.out.println("Error: " + t.getMessage());
    }

    public Session getSession() {
        return this.session;
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app>
    <display-name>WebSocket application</display-name>
    <servlet>
        <servlet-name>XYZWebSocketServlet</servlet-name>
        <servlet-class>com.newKinpo.servlet.XYZWebSocketServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>XYZWebSocketServlet</servlet-name>
        <url-pattern>/events/*</url-pattern>
    </servlet-mapping>
</web-app>

@WebSocket
公共类XYZWebSocketEvent{
非公开会议；
@OnWebSocketConnect
公共连接无效（会话sess）{
会话=sess；
//在客户端连接到服务器时获取参数
映射参数=session.getUpgradeRequest（）.getParameterMap（）；
字符串encyptedID=parameters.get（“ID”）.get（0）；
System.out.println（“连接：+session.getRemoteAddress（）.getPort（））；
试一试{
session.setIdleTimeout（600000）；
session.getRemote（）.sendString（“Hello！”）；
}捕获（ioe异常ioe）{
ioe.printStackTrace（）；
}
}
@OnWebSocketMessage
公共消息无效（字符串消息）{
试试{
session.getRemote（）.sendString（“Message:+Message”）；
}
捕获（例外情况除外）{
}
}
@OnWebSocketClose
public void onClose（int statusCode，字符串原因）{
试一试{
session.getRemote（）.sendString（“关闭：statusCode=“+statusCode+”，reason=“+reason”）；
}
捕获（例外情况除外）{
}
}
@OnWebSocketError
公共作废登记员（可丢弃的t）{
System.out.println（“错误：+t.getMessage（））；
}
公共会话getSession（）{
返回此会话；
}
}

web.xml:

@SuppressWarnings("serial")
public class XYZWebSocketServlet extends WebSocketServlet{
    @Override
    public void configure(WebSocketServletFactory factory) {
        factory.getPolicy().setIdleTimeout(600000);
        factory.register(XYZWebSocketEvent.class);
    }
}

@WebSocket
public class XYZWebSocketEvent {
    private Session session;

    @OnWebSocketConnect
    public void onConnect(Session sess) {
        session = sess;

        // Get parameters while client connect to server
        Map<String,List<String>> parameters = session.getUpgradeRequest().getParameterMap();
        String encyptedID = parameters.get("ID").get(0);

        System.out.println("Connect: " + session.getRemoteAddress().getPort());
        try {
            session.setIdleTimeout(600000);
            session.getRemote().sendString("Hello!");
        } catch (IOException ioe) {
            ioe.printStackTrace();
        }
    }

    @OnWebSocketMessage
    public void onMessage(String message) {
            try {   
                session.getRemote().sendString("Message: " + message);
            }
            catch (Exception ex) {
            }
    }

    @OnWebSocketClose
    public void onClose(int statusCode, String reason) {
            try {
                session.getRemote().sendString("Close: statusCode=" + statusCode + ", reason=" +reason);
        }
            catch (Exception ex) {
            }
    }

    @OnWebSocketError
    public void onError(Throwable t) {
        System.out.println("Error: " + t.getMessage());
    }

    public Session getSession() {
        return this.session;
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app>
    <display-name>WebSocket application</display-name>
    <servlet>
        <servlet-name>XYZWebSocketServlet</servlet-name>
        <servlet-class>com.newKinpo.servlet.XYZWebSocketServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>XYZWebSocketServlet</servlet-name>
        <url-pattern>/events/*</url-pattern>
    </servlet-mapping>
</web-app>

WebSocket应用程序
XYZWebSocketServlet
com.newKinpo.servlet.XYZWebSocketServlet
XYZWebSocketServlet
/事件/*

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有什么不对劲吗？谢谢您的关注。

我遇到了类似的问题，我已经找到了原因和解决方案。嵌入式jetty服务器由SUN类加载器加载（稍后将称之为系统类加载器），在扫描webapp目录后，我的应用由webapp类加载器加载，当涉及WebSocketServerFactory时，由webapp加载。但是，从请求中获得的org.eclipse.jetty.server.HttpConnection对象由系统类加载器加载

根据jetty，websocket包被视为系统类包，如果系统已经加载，则不应由WebApp加载

解决方案是在jetty服务器初始化时强制加载包org.eclipse.jetty.websocket

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例如，我只是创建WebSocketHandler的虚拟实例。强制加载包的选项有很多，但它们与此问题无关。

能否提供有关虚拟实例的更多详细信息