servlets - 使用Spark Web框架时如何使用 native Servlet筛选器？

Question

我在玩Spark(Java Web框架，而不是Apache Spark)。

我发现定义路由和过滤器确实很好，而且很容易，但是我希望将 native servlet过滤器应用于路由，似乎找不到找到这种方法的方法。

更具体地说，我想使用Jetty's DoSFilter，它是一个servlet过滤器(与Spark Filter定义相反)。由于Spark使用的是嵌入式Jetty，因此我没有web.xml来注册DoSFilter。但是，Spark不会公开服务器实例，因此我也找不到一种以编程方式注册筛选器的优雅方法。

有没有办法将本地servlet过滤器应用于我的路由？

我曾想将DoSFilter封装在自己的Spark过滤器中，但这似乎是一个奇怪的想法。

Answer 1

您可以这样做:

public class App {
 private static Logger LOG = LoggerFactory.getLogger(App.class);

 public static void main(String[] args) throws Exception {

    ServletContextHandler mainHandler = new ServletContextHandler();
    mainHandler.setContextPath("/base/path");

    Stream.of(
            new FilterHolder(new MyServletFilter()),
            new FilterHolder(new SparkFilter()) {{
                this.setInitParameter("applicationClass", SparkApp.class.getName());
            }}
    ).forEach(h -> mainHandler.addFilter(h, "*", null));

    GzipHandler compression = new GzipHandler();
    compression.setIncludedMethods("GET");
    compression.setMinGzipSize(512);
    compression.setHandler(mainHandler);

    Server server = new Server(new ExecutorThreadPool(new ThreadPoolExecutor(10,200,60000,TimeUnit.MILLISECONDS,
                                                                          new ArrayBlockingQueue<>(200),
                                                                       new CustomizableThreadFactory("jetty-pool-"))));

    final ServerConnector serverConnector = new ServerConnector(server);
    serverConnector.setPort(9290);
    server.setConnectors(new Connector[] { serverConnector });

    server.setHandler(compression);
    server.start();

    hookToShutdownEvents(server);

    server.join();
}

private static void hookToShutdownEvents(final Server server) {
    LOG.debug("Hooking to JVM shutdown events");

    server.addLifeCycleListener(new AbstractLifeCycle.AbstractLifeCycleListener() {

        @Override
        public void lifeCycleStopped(LifeCycle event) {
            LOG.info("Jetty Server has been stopped");
            super.lifeCycleStopped(event);
        }

    });

    Runtime.getRuntime().addShutdownHook(new Thread() {
        @Override
        public void run() {
            LOG.info("About to stop Jetty Server due to JVM shutdown");
            try {
                server.stop();
            } catch (Exception e) {
                LOG.error("Could not stop Jetty Server properly", e);
            }
        }
    });
}

/**
 * @implNote {@link SparkFilter} needs to access a public class
 */
@SuppressWarnings("WeakerAccess")
public static class SparkApp implements SparkApplication {

    @Override
    public void init() {
        System.setProperty("spring.profiles.active", ApplicationProfile.readProfilesOrDefault("dev").stream().collect(Collectors.joining()));
        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(ModocContext.class);
        ctx.registerShutdownHook();
    }

}}