使用 apache Camel 创建 Rest 服务时出现错误

问题描述 投票：0回答：3

由于我对 Apache Camel 特别是 Rest DSL 还很陌生，所以我想尝试一下 Rest DSL 的示例。

所以我创建了一个camel-config.xml：

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:camel="http://camel.apache.org/schema/spring"
       xsi:schemaLocation="
         http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
         http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/camel-spring.xsd">

  <!-- use camel-metrics route policy to gather metrics for all routes -->
  <!-- bean id="metricsRoutePolicyFactory" class="org.apache.camel.component.metrics.routepolicy.MetricsRoutePolicyFactory"/-->

  <!-- a rest service which uses binding to/from pojos -->
  <bean id="userRoutes" class="org.apache.camel.example.rest.UserRouteBuilder"/>

  <!-- a bean for user services -->
  <bean id="userService" class="org.apache.camel.example.rest.UserService"/>

  <camelContext id="myCamel" xmlns="http://camel.apache.org/schema/spring">
    <routeBuilder ref="userRoutes"/>
  </camelContext>

</beans>

我的路线类别是：

package org.apache.camel.example.rest;

import org.apache.camel.builder.RouteBuilder;

/**
 * Define REST services using the Camel REST DSL
 */
public class UserRouteBuilder extends RouteBuilder {

    public void configure() throws Exception {
        rest("/say").get("/hello").to("direct:hello").get("/bye")
                .consumes("application/json").to("direct:bye").post("/bye")
                .to("mock:update");
        from("direct:hello").transform().constant("Hello World");
        from("direct:bye").transform().constant("Bye World");
    }

}

我的 web.xml 是：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>My Camel Rest Application</display-name>

  <!-- location of Camel Spring xml files -->
  <context-param>
    <param-name>contextConfigLocation</param-name>

    <!-- to use Java DSL -->
    <param-value>classpath:camel-config.xml</param-value>

    <!-- to use XML DSL, then enable me, and disable Java DSL above
    <param-value>classpath:camel-config-xml.xml</param-value>
    -->
  </context-param>

  <!-- the listener that kick-starts Spring -->
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>

  <!-- to setup Camel Servlet -->
  <servlet>
    <display-name>Camel Http Transport Servlet</display-name>
    <servlet-name>CamelServlet</servlet-name>
    <servlet-class>org.apache.camel.component.servlet.CamelHttpTransportServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>

  <!-- START SNIPPET: e1 -->
  <!-- to setup Camel Swagger api servlet -->
  <servlet>
    <servlet-name>ApiDeclarationServlet</servlet-name>
    <servlet-class>org.apache.camel.component.swagger.DefaultCamelSwaggerServlet</servlet-class>
    <init-param>
      <!-- we specify the base.path using relative notation, that means the actual path will be calculated at runtime as
           http://server:port/contextpath/rest -->
      <param-name>base.path</param-name>
      <param-value>rest</param-value>
    </init-param>
    <init-param>
      <!-- we specify the api.path using relative notation, that means the actual path will be calculated at runtime as
           http://server:port/contextpath/api-docs -->
      <param-name>api.path</param-name>
      <param-value>api-docs</param-value>
    </init-param>
    <init-param>
      <param-name>api.version</param-name>
      <param-value>1.2.3</param-value>
    </init-param>
    <init-param>
      <param-name>api.title</param-name>
      <param-value>User Services</param-value>
    </init-param>
    <init-param>
      <param-name>api.description</param-name>
      <param-value>Camel Rest Example with Swagger that provides an User REST service</param-value>
    </init-param>
    <load-on-startup>2</load-on-startup>
  </servlet>

  <!-- swagger api declaration -->
  <servlet-mapping>
    <servlet-name>ApiDeclarationServlet</servlet-name>
    <url-pattern>/api-docs/*</url-pattern>
  </servlet-mapping>
  <!-- END SNIPPET: e1 -->

  <!-- define that url path for the Camel Servlet to use -->
  <servlet-mapping>
    <servlet-name>CamelServlet</servlet-name>
    <url-pattern>/rest/*</url-pattern>
  </servlet-mapping>

  <!-- START SNIPPET: e2 -->
  <!-- enable CORS filter so people can use swagger ui to browse and test the apis -->
  <filter>
    <filter-name>RestSwaggerCorsFilter</filter-name>
    <filter-class>org.apache.camel.component.swagger.RestSwaggerCorsFilter</filter-class>
  </filter>

  <filter-mapping>
    <filter-name>RestSwaggerCorsFilter</filter-name>
    <url-pattern>/api-docs/*</url-pattern>
    <url-pattern>/rest/*</url-pattern>
  </filter-mapping>
  <!-- END SNIPPET: e2 -->

  <welcome-file-list>
      <welcome-file>home.html</welcome-file>
  </welcome-file-list>

</web-app>

现在我已经创建了我的restProject的war文件，并将其部署在tomcat上。在tomcat的lib文件夹中提供了所有必需的jar。我正在使用骆驼2.14。

现在当我启动我的tomcat时，在启动过程中我收到错误：

SEVERE: Context initialization failed
org.apache.camel.RuntimeCamelException: java.lang.IllegalStateException: Cannot find RestConsumerFactory in Registry or
as a Component to use
        at org.apache.camel.util.ObjectHelper.wrapRuntimeCamelException(ObjectHelper.java:1364)
        at org.apache.camel.spring.SpringCamelContext.onApplicationEvent(SpringCamelContext.java:122)
        at org.apache.camel.spring.CamelContextFactoryBean.onApplicationEvent(CamelContextFactoryBean.java:327)
        at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMult
icaster.java:96)
        at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:3
34)
        at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:
948)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
        at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:389
)
        at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:294)
        at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
        at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4791)
        at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5285)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:618)
        at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1100)
        at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1618)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
        at java.util.concurrent.FutureTask.run(FutureTask.java:166)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
        at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.IllegalStateException: Cannot find RestConsumerFactory in Registry or as a Component to use
        at org.apache.camel.component.rest.RestEndpoint.createConsumer(RestEndpoint.java:238)
        at org.apache.camel.impl.EventDrivenConsumerRoute.addServices(EventDrivenConsumerRoute.java:65)
        at org.apache.camel.impl.DefaultRoute.onStartingServices(DefaultRoute.java:80)
        at org.apache.camel.impl.RouteService.warmUp(RouteService.java:134)
        at org.apache.camel.impl.DefaultCamelContext.doWarmUpRoutes(DefaultCamelContext.java:2379)
        at org.apache.camel.impl.DefaultCamelContext.safelyStartRouteServices(DefaultCamelContext.java:2309)
        at org.apache.camel.impl.DefaultCamelContext.doStartOrResumeRoutes(DefaultCamelContext.java:2091)
        at org.apache.camel.impl.DefaultCamelContext.doStartCamel(DefaultCamelContext.java:1951)
        at org.apache.camel.impl.DefaultCamelContext.doStart(DefaultCamelContext.java:1777)
        at org.apache.camel.support.ServiceSupport.start(ServiceSupport.java:61)
        at org.apache.camel.impl.DefaultCamelContext.start(DefaultCamelContext.java:1745)
        at org.apache.camel.spring.SpringCamelContext.maybeStart(SpringCamelContext.java:254)
        at org.apache.camel.spring.SpringCamelContext.onApplicationEvent(SpringCamelContext.java:120)
        ... 22 more

过去两天我一直在试图弄清楚为什么我会收到此错误。 非常期待您的解决方案。预先感谢..

java apache rest tomcat apache-camel
3个回答
23
投票

您需要对其余 DSL 进行额外配置。 http://camel.apache.org/rest-dsl.html中描述的4个组件支持Rest DSL。请查看[支持Rest DSL的组件]部分。有关配置，请查看[配置Rest DSL] DSL]部分

您实际上需要的是另外 2 个补充。

1）在您的路线构建器中的其余配置部分。对于 servlet 组件，可能是 

restConfiguration().component("servlet")
->此处有更多选项。

在此示例

中查找完整配置

2）在pom.xml中添加依赖。

<dependency>
   <groupId>org.apache.camel</groupId>
   <artifactId>camel-servlet</artifactId>
</dependency>

有关 Spark-Rest 配置，请查看代码 here

6
投票

如果您正在运行 Camel-Spring Boot 应用程序，您可以通过在 pom.xml 中添加以下依赖项来解决该问题：

<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-http-starter</artifactId>
</dependency>
0
投票

我在处理 Camel-Spring Boot 项目（使用 Camel 版本 4.4.2）时收到了相同的异常，并通过将此依赖项添加到我的 pom.xml 来解决它：

<dependency>
   <groupId>org.apache.camel</groupId>
   <artifactId>camel-openapi-java-starter</artifactId>
</dependency>
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