在Camel 2.15中配置Jetty组件

Question

我正试着开始使用Jetty和Camel。我已经将依赖添加到我的pom中：

    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-jetty</artifactId>
        <version>2.15.5</version>
    </dependency>

我的CamelContext初始化如下：

public void startCamelContext() throws Exception {
    CamelContext camelContext = new DefaultCamelContext(); 
    camelContext.addComponent("jetty", new JettyHttpComponent8());
    camelContext.start();
}

当我尝试启动我的服务时，它有一个端点定义为：

jetty:http://0.0.0.0:9000/httpInput

我得到了一个异常：

java.lang.NullPointerException: null
at org.apache.camel.component.jetty8.JettyHttpComponent8.createConnectorJettyInternal(JettyHttpComponent8.java:48)
at org.apache.camel.component.jetty.JettyHttpComponent.createConnector(JettyHttpComponent.java:585)
at org.apache.camel.component.jetty.JettyHttpComponent.getSocketConnector(JettyHttpComponent.java:527)
at org.apache.camel.component.jetty.JettyHttpComponent.getConnector(JettyHttpComponent.java:517)
at org.apache.camel.component.jetty.JettyHttpComponent.connect(JettyHttpComponent.java:320)
at org.apache.camel.component.http.HttpEndpoint.connect(HttpEndpoint.java:185)
at org.apache.camel.component.http.HttpConsumer.doStart(HttpConsumer.java:53)
at org.apache.camel.support.ServiceSupport.start(ServiceSupport.java:61)
at org.apache.camel.impl.DefaultCamelContext.startService(DefaultCamelContext.java:2885)
at org.apache.camel.impl.DefaultCamelContext.doStartOrResumeRouteConsumers(DefaultCamelContext.java:3179)
at org.apache.camel.impl.DefaultCamelContext.doStartRouteConsumers(DefaultCamelContext.java:3115)
at org.apache.camel.impl.DefaultCamelContext.safelyStartRouteServices(DefaultCamelContext.java:3045)
at org.apache.camel.impl.DefaultCamelContext.doStartOrResumeRoutes(DefaultCamelContext.java:2813)
at org.apache.camel.impl.DefaultCamelContext.startAllRoutes(DefaultCamelContext.java:865)

关于如何设置Jetty组件的文档充其量是缺乏的。我发现了一个邮件列表条目，上面说从Camel2.15开始JettyHttpComponent就被抽象了，现在必须使用JettyHttpComponent8或9配置该组件。link

在我的例子中，我使用的是Camel2.15.5，而JettyHttpComponent9在类路径中不可用，而使用8则会产生上述异常。我还找到了相关的讨论here，没有关于如何实际使用该组件的信息。

Answer 1

这通常不是CamelContext的初始化/启动方式。请考虑使用原型开始，然后添加Jetty Maven依赖项，并查看错误是否可以重现。

骆驼原型可以在这里找到：http://camel.apache.org/camel-maven-archetypes.html

Answer 2

要在spring之外启动一个驼峰上下文，您需要创建一个连续的线程来保持驼峰的存活，如下所示：http://camel.apache.org/running-camel-standalone-and-have-it-keep-running.html

别担心，我有下面的一些代码，可以在localhost:8081上为你设置一个码头：

pom.xml

    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-jetty</artifactId>
        <version>2.16.1</version>
    </dependency>

    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-core</artifactId>
        <version>2.16.1</version>
    </dependency>


import org.apache.camel.Exchange;
import org.apache.camel.Processor;
import org.apache.camel.builder.RouteBuilder;
import org.apache.camel.main.Main;
import org.apache.camel.main.MainListenerSupport;
import org.apache.camel.main.MainSupport;

import java.util.Date;

/**
 * Created by mkbrv on 22/06/16.
 */
public class CamelJetty {

        private Main main;

        public static void main(String[] args) throws Exception {
            CamelJetty example = new CamelJetty();
            example.boot();
        }

        public void boot() throws Exception {
            // create a Main instance
            main = new Main();
            // bind MyBean into the registry
            main.bind("foo", new MyBean());
            // add routes
            main.addRouteBuilder(new MyJettyRouteBuilder());
            // add event listener
            main.addMainListener(new Events());

            // run until you terminate the JVM
            System.out.println("Starting Camel. Use ctrl + c to terminate the JVM.\n");
            main.run();
        }

        private static class MyJettyRouteBuilder extends RouteBuilder {
            @Override
            public void configure() throws Exception {
                from("jetty:http://localhost:8081")
                        .process(exchange -> {
                            System.out.println("Invoked timer at " + new Date());
                            exchange.getOut().setBody("Hi, this is Camel!");
                        })
                        .bean("foo");
            }
        }

        public static class MyBean {
            public void callMe() {
                System.out.println("MyBean.callMe method has been called");
            }
        }

        public static class Events extends MainListenerSupport {

            @Override
            public void afterStart(MainSupport main) {
                System.out.println("MainExample with Camel is now started!");
            }

            @Override
            public void beforeStop(MainSupport main) {
                System.out.println("MainExample with Camel is now being stopped!");
            }
        }
    }

接下来，只需转到http://localhost:8081，您应该会看到一条欢迎消息。在这方面做进一步的调整会很有趣。