Jetty 9.0 嵌入和 RestEasy 3.0 不断抛出 NoSuchMethodError

Question

今天我有了构建一个非常简单的 Web 应用程序的想法，该应用程序将由 REST 后端提供支持。因为我想要一个非常轻量级的服务器，所以我开始研究 Jetty。因为我想尝试另一个 JAX-RS 实现而不是 Jersey，所以我查看了 RestEasy。我认为这两个很容易实现。我错了...

我导入了基本的 Jetty 服务器和 servlet 依赖项，因为我认为这是基本(仅限 REST)Jetty 服务器的唯一服务器要求(我也尝试使用 webapp 依赖项；这给出了相同的错误)。

<dependency>
    <groupId>org.eclipse.jetty</groupId>
    <artifactId>jetty-server</artifactId>
    <version>9.0.0.RC0</version>
    <scope>compile</scope>
</dependency>
<dependency>
    <groupId>org.eclipse.jetty</groupId>
    <artifactId>jetty-servlet</artifactId>
    <version>9.0.0.RC0</version>
    <scope>compile</scope>
</dependency>
<dependency>
    <groupId>org.eclipse.jetty</groupId>
    <artifactId>jetty-servlets</artifactId>
    <version>9.0.0.RC0</version>
    <scope>compile</scope>
</dependency>

然后我导入了基本的 RestEasy 依赖项。

<dependency>
    <groupId>org.jboss.resteasy</groupId>
    <artifactId>resteasy-jaxrs</artifactId>
    <version>3.0.1.Final</version>
    <scope>compile</scope>
</dependency>
<dependency>
    <groupId>org.jboss.resteasy</groupId>
    <artifactId>resteasy-jaxb-provider</artifactId>
    <version>3.0.1.Final</version>
    <scope>compile</scope>
</dependency>
<dependency>
    <groupId>org.jboss.resteasy</groupId>
    <artifactId>async-http-servlet-3.0</artifactId>
    <version>3.0.1.Final</version>
    <scope>compile</scope>
</dependency>

主要方法:

public class ExampleActivator {
    public static void main(String args[]) throws Exception {
        Server server = new Server(8080);
        ServletContextHandler context = new ServletContextHandler(ServletContextHandler.NO_SESSIONS);
        context.setContextPath("/");
        ServletHolder h = new ServletHolder(new HttpServlet30Dispatcher());
        h.setInitParameter("javax.ws.rs.Application", "packages.ExampleResources");
        context.addServlet(h, "/*");
        server.setHandler(context);
        server.start();
        server.join();
    }
}

示例资源:

public class ExampleResources extends Application {

    private static final ImmutableSet services = ImmutableSet.of(
            ExampleResourceImpl.class
    );

    @Override
    public Set<Class<?>> getClasses() {
        return services;
    }
}

示例资源Impl:

@Path("activities")
public class ExampleResourceImpl {

    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public String getAll() {
        return "Hello World";
    }
}

当我转到网页时，我得到以下跟踪:

250 [main] INFO org.eclipse.jetty.server.Server - jetty-9.0.0.RC0
911 [main] INFO org.jboss.resteasy.spi.ResteasyDeployment - Deploying javax.ws.rs.core.Application: class packages.ExampleResources
939 [main] INFO org.jboss.resteasy.spi.ResteasyDeployment - Adding class resource packages.ExampleResourceImpl from Application class packages.ExampleResources
1005 [main] INFO org.eclipse.jetty.server.handler.ContextHandler - started o.e.j.s.ServletContextHandler@702ab48{/,null,AVAILABLE}
1037 [main] INFO org.eclipse.jetty.server.ServerConnector - Started ServerConnector@465ed596{HTTP/1.1}{0.0.0.0:8080}
6315 [qtp84346444-13] WARN org.eclipse.jetty.servlet.ServletHandler - Error for /activities
java.lang.NoSuchMethodError: org.jboss.resteasy.specimpl.BuiltResponse.getHeaders()Ljavax/ws/rs/core/MultivaluedMap;
    at org.jboss.resteasy.core.ServerResponseWriter.setDefaultContentType(ServerResponseWriter.java:195)
    at org.jboss.resteasy.core.ServerResponseWriter.writeNomapResponse(ServerResponseWriter.java:46)
    at org.jboss.resteasy.core.SynchronousDispatcher.writeResponse(SynchronousDispatcher.java:411)
    at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:376)
    at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:179)
    at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:220)
    at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:56)
    at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:51)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
    at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:671)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:448)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1070)
    at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:375)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1004)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:136)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
    at org.eclipse.jetty.server.Server.handle(Server.java:449)
    at org.eclipse.jetty.server.HttpChannel.run(HttpChannel.java:246)
    at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:265)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.run(AbstractConnection.java:240)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:589)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:520)
    at java.lang.Thread.run(Thread.java:722)

通常这意味着我忘记了一个依赖项，但是我真的不知道发生了什么。

Answer 1

我只是偶然发现了同样的问题。解决方案是将 jaxrs-api 显式添加为依赖项列表中的第一个依赖项。

<dependencies>
  <!-- jaxrs-api is the very first dependency -->
  <dependency>
    <groupId>org.jboss.resteasy</groupId>
    <artifactId>jaxrs-api</artifactId>
    <version>3.0.4.Final</version>
  </dependency>
  <!-- here come the other depdendencies -->
</dependencies> 

Jackson 使用提供相同的 jsr311-api Response BuiltResponse 使用的类类(class)。不幸的是，这个Response不包含 getHeaders()方法。因此，即使解决了依赖关系，它也使用了错误的类。如果以某种方式 jackson 依赖在 Resteasy 之前获得，那么上面的异常将被引发。