我正在我的应用程序中嵌入 jetty 以通过 websocket 进行通信，如何定义不同的路径？

Question

我有一个java服务器，它需要与web客户端实时通信。为了做到这一点，我正在嵌入Jetty 9。Jetty将作为web客户端的静态web服务器，以及websocket服务器。根据我在网上找到的示例，静态页面处理程序和WS处理程序都是通过同一路径提供的。我不清楚如何让码头从两条不同的道路为他们服务。如果有什么建议，我将不胜感激。这是我的代码

public static void main(String ...args) throws Exception {
    Server server = new Server(8080);
    ResourceHandler resource_handler = new ResourceHandler();
    resource_handler.setDirectoriesListed(true);
    resource_handler.setWelcomeFiles(new String[]{ "index.html" });
    resource_handler.setResourceBase("./webapp");

    WebSocketHandler wsHandler = new WebSocketHandler() {
        @Override
        public void configure(WebSocketServletFactory factory) {
            factory.register(MyWebSocketHandler.class);
        }
    };
    HandlerList handlers = new HandlerList();
    handlers.setHandlers(new Handler[] { resource_handler,wsHandler, new DefaultHandler() });
    server.setHandler(handlers);
    server.start();
    server.join();
}

Answer 1

使用ContextHandlerCollection并将WebSockets包装在ContextHandler对象中。

    ContextHandlerCollection contexts = new ContextHandlerCollection();
    contexts.addHandler(new ContextHandler(wsFooHandler, "/foo"));
    contexts.addHandler(new ContextHandler(wsBarHandler, "/bar"));
    HandlerList handlers = new HandlerList();
    handlers.setHandlers(new Handler[] { resource_handler, contexts, new DefaultHandler() });

然而，将ServletContextHandler与WebSocketUpgradeFilter及其addMapping一起使用，可以以更强大的方式控制websocket的创建。

示例：

public static void main(String... args) throws Exception
{
    Server server = new Server(8080);
    ServletContextHandler context = new ServletContextHandler();
    context.setContextPath("/");
    context.setWelcomeFiles(new String[] { "index.html" });
    WebSocketUpgradeFilter filter = WebSocketUpgradeFilter.configureContext(context);
    filter.addMapping(new ServletPathSpec("/foo/*"),new SingleWebSocketCreator(FooSocket.class));
    filter.addMapping(new ServletPathSpec("/bar/*"),new SingleWebSocketCreator(BarSocket.class));
    filter.addMapping(new ServletPathSpec("/*.ws"),new SingleWebSocketCreator(WsTypeSocket.class));
    filter.addMapping(new RegexPathSpec("/chat/room/[a-zA-z_]*/public"),new SingleWebSocketCreator(ChatSocket.class));
    // add your own non-websocket servlets
    context.addServlet(HelloServlet.class,"/hello");
    // Lastly, the default servlet for root content (serves up static content)
    // It is important that this is last.
    ServletHolder holderPwd = new ServletHolder("default", DefaultServlet.class);
    holderPwd.setInitParameter("resourceBase","./webapp");
    holderPwd.setInitParameter("dirAllowed","true");
    context.addServlet(holderPwd,"/");
    HandlerList handlers = new HandlerList();
    handlers.setHandlers(new Handler[] { context, new DefaultHandler() });
    server.setHandler(handlers);
    server.start();
    server.join();
}

意外遗漏的SingleWebSocketCreator。。。

public class SingleWebSocketCreator implements WebSocketCreator
{
    private Class<?> endpoint;
    public SingleWebSocketCreator(Class<?> websocketEndpoint)
    {
        this.endpoint = websocketEndpoint;
    }
    @Override
    public Object createWebSocket(ServletUpgradeRequest req, ServletUpgradeResponse resp)
    {
        try
        {
            // new instance of endpoint for each upgrade
            return endpoint.newInstance();
        }
        catch (InstantiationException | IllegalAccessException e)
        {
            // failure to instantiate can flow out
            throw new RuntimeException(e);
        }
    }
}