Chapter 301. Servlet Component Available as of Camel version 2.0 The servlet: component provides HTTP based endpoints for consuming HTTP requests that arrive at a HTTP endpoint that is bound to a published Servlet. Maven users will need to add the following dependency to their pom.xml for this component: <dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-servlet</artifactId> <version>x.x.x</version> <!-- use the same version as your Camel core version --> </dependency> Note Stream Servlet is stream based, which means the input it receives is submitted to Camel as a stream. That means you will only be able to read the content of the stream once . If you find a situation where the message body appears to be empty or you need to access the data multiple times (eg: doing multicasting, or redelivery error handling) you should use Stream caching or convert the message body to a String which is safe to be read multiple times. 301.1. URI format servlet://relative_path[?options] You can append query options to the URI in the following format: ?option=value&option=value&... 301.2. Options The Servlet component supports 9 options, which are listed below. Name Description Default Type servletName (consumer) Default name of servlet to use. The default name is CamelServlet. CamelServlet String httpRegistry (consumer) To use a custom org.apache.camel.component.servlet.HttpRegistry. HttpRegistry attachmentMultipart Binding (consumer) Whether to automatic bind multipart/form-data as attachments on the Camel Exchange. The options attachmentMultipartBinding=true and disableStreamCache=false cannot work together. Remove disableStreamCache to use AttachmentMultipartBinding. This is turn off by default as this may require servlet specific configuration to enable this when using Servlet's. false boolean fileNameExtWhitelist (consumer) Whitelist of accepted filename extensions for accepting uploaded files. Multiple extensions can be separated by comma, such as txt,xml. String httpBinding (advanced) To use a custom HttpBinding to control the mapping between Camel message and HttpClient. HttpBinding httpConfiguration (advanced) To use the shared HttpConfiguration as base configuration. HttpConfiguration allowJavaSerialized Object (advanced) Whether to allow java serialization when a request uses context-type=application/x-java-serialized-object. This is by default turned off. If you enable this then be aware that Java will deserialize the incoming data from the request to Java and that can be a potential security risk. false boolean headerFilterStrategy (filter) To use a custom org.apache.camel.spi.HeaderFilterStrategy to filter header to and from Camel message. HeaderFilterStrategy resolveProperty Placeholders (advanced) Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders. true boolean The Servlet endpoint is configured using URI syntax: with the following path and query parameters: 301.2.1. Path Parameters (1 parameters): Name Description Default Type contextPath Required The context-path to use String 301.2.2. Query Parameters (22 parameters): Name Description Default Type disableStreamCache (common) Determines whether or not the raw input stream from Servlet is cached or not (Camel will read the stream into a in memory/overflow to file, Stream caching) cache. By default Camel will cache the Servlet input stream to support reading it multiple times to ensure it Camel can retrieve all data from the stream. However you can set this option to true when you for example need to access the raw stream, such as streaming it directly to a file or other persistent store. DefaultHttpBinding will copy the request input stream into a stream cache and put it into message body if this option is false to support reading the stream multiple times. If you use Servlet to bridge/proxy an endpoint then consider enabling this option to improve performance, in case you do not need to read the message payload multiple times. The http/http4 producer will by default cache the response body stream. If setting this option to true, then the producers will not cache the response body stream but use the response stream as-is as the message body. false boolean headerFilterStrategy (common) To use a custom HeaderFilterStrategy to filter header to and from Camel message. HeaderFilterStrategy httpBinding (common) To use a custom HttpBinding to control the mapping between Camel message and HttpClient. HttpBinding async (consumer) Configure the consumer to work in async mode false boolean bridgeErrorHandler (consumer) Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored. false boolean chunked (consumer) If this option is false the Servlet will disable the HTTP streaming and set the content-length header on the response true boolean httpMethodRestrict (consumer) Used to only allow consuming if the HttpMethod matches, such as GET/POST/PUT etc. Multiple methods can be specified separated by comma. String matchOnUriPrefix (consumer) Whether or not the consumer should try to find a target consumer by matching the URI prefix if no exact match is found. false boolean responseBufferSize (consumer) To use a custom buffer size on the javax.servlet.ServletResponse. Integer servletName (consumer) Name of the servlet to use CamelServlet String transferException (consumer) If enabled and an Exchange failed processing on the consumer side, and if the caused Exception was send back serialized in the response as a application/x-java-serialized-object content type. On the producer side the exception will be deserialized and thrown as is, instead of the HttpOperationFailedException. The caused exception is required to be serialized. This is by default turned off. If you enable this then be aware that Java will deserialize the incoming data from the request to Java and that can be a potential security risk. false boolean attachmentMultipartBinding (consumer) Whether to automatic bind multipart/form-data as attachments on the Camel Exchange. The options attachmentMultipartBinding=true and disableStreamCache=false cannot work together. Remove disableStreamCache to use AttachmentMultipartBinding. This is turn off by default as this may require servlet specific configuration to enable this when using Servlet's. false boolean eagerCheckContentAvailable (consumer) Whether to eager check whether the HTTP requests has content if the content-length header is 0 or not present. This can be turned on in case HTTP clients do not send streamed data. false boolean exceptionHandler (consumer) To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored. ExceptionHandler exchangePattern (consumer) Sets the exchange pattern when the consumer creates an exchange. ExchangePattern fileNameExtWhitelist (consumer) Whitelist of accepted filename extensions for accepting uploaded files. Multiple extensions can be separated by comma, such as txt,xml. String optionsEnabled (consumer) Specifies whether to enable HTTP OPTIONS for this Servlet consumer. By default OPTIONS is turned off. false boolean traceEnabled (consumer) Specifies whether to enable HTTP TRACE for this Servlet consumer. By default TRACE is turned off. false boolean mapHttpMessageBody (advanced) If this option is true then IN exchange Body of the exchange will be mapped to HTTP body. Setting this to false will avoid the HTTP mapping. true boolean mapHttpMessageFormUrl EncodedBody (advanced) If this option is true then IN exchange Form Encoded body of the exchange will be mapped to HTTP. Setting this to false will avoid the HTTP Form Encoded body mapping. true boolean mapHttpMessageHeaders (advanced) If this option is true then IN exchange Headers of the exchange will be mapped to HTTP headers. Setting this to false will avoid the HTTP Headers mapping. true boolean synchronous (advanced) Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported). false boolean 301.3. Spring Boot Auto-Configuration The component supports 13 options, which are listed below. Name Description Default Type camel.component.servlet.allow-java-serialized-object Whether to allow java serialization when a request uses context-type=application/x-java-serialized-object. This is by default turned off. If you enable this then be aware that Java will deserialize the incoming data from the request to Java and that can be a potential security risk. false Boolean camel.component.servlet.attachment-multipart-binding Whether to automatic bind multipart/form-data as attachments on the Camel Exchange. The options attachmentMultipartBinding=true and disableStreamCache=false cannot work together. Remove disableStreamCache to use AttachmentMultipartBinding. This is turn off by default as this may require servlet specific configuration to enable this when using Servlet's. false Boolean camel.component.servlet.enabled Enable servlet component true Boolean camel.component.servlet.file-name-ext-whitelist Whitelist of accepted filename extensions for accepting uploaded files. Multiple extensions can be separated by comma, such as txt,xml. String camel.component.servlet.header-filter-strategy To use a custom org.apache.camel.spi.HeaderFilterStrategy to filter header to and from Camel message. The option is a org.apache.camel.spi.HeaderFilterStrategy type. String camel.component.servlet.http-binding To use a custom HttpBinding to control the mapping between Camel message and HttpClient. The option is a org.apache.camel.http.common.HttpBinding type. String camel.component.servlet.http-configuration To use the shared HttpConfiguration as base configuration. The option is a org.apache.camel.http.common.HttpConfiguration type. String camel.component.servlet.http-registry To use a custom org.apache.camel.component.servlet.HttpRegistry. The option is a org.apache.camel.component.servlet.HttpRegistry type. String camel.component.servlet.mapping.context-path Context path used by the servlet component for automatic mapping. /camel/* String camel.component.servlet.mapping.enabled Enables the automatic mapping of the servlet component into the Spring web context. true Boolean camel.component.servlet.mapping.servlet-name The name of the Camel servlet. CamelServlet String camel.component.servlet.resolve-property-placeholders Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders. true Boolean camel.component.servlet.servlet-name Default name of servlet to use. The default name is CamelServlet. CamelServlet String 301.4. Message Headers Camel will apply the same Message Headers as the HTTP component. Camel will also populate all request.parameter and request.headers . For example, if a client request has the URL, http://myserver/myserver?orderid=123 , the exchange will contain a header named orderid with the value 123. 301.5. Usage You can consume only from endpoints generated by the Servlet component. Therefore, it should be used only as input into your Camel routes. To issue HTTP requests against other HTTP endpoints, use the HTTP Component . 301.6. Putting Camel JARs in the app server boot classpath If you put the Camel JARs such as camel-core , camel-servlet , etc. in the boot classpath of your application server (eg usually in its lib directory), then mind that the servlet mapping list is now shared between multiple deployed Camel application in the app server. Mind that putting Camel JARs in the boot classpath of the application server is generally not best practice! So in those situations you must define a custom and unique servlet name in each of your Camel application, eg in the web.xml define: <servlet> <servlet-name>MyServlet</servlet-name> <servlet-class>org.apache.camel.component.servlet.CamelHttpTransportServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>MyServlet</servlet-name> <url-pattern>/*</url-pattern> </servlet-mapping> And in your Camel endpoints then include the servlet name as well <route> <from uri="servlet://foo?servletName=MyServlet"/> ... </route> From Camel 2.11 onwards Camel will detect this duplicate and fail to start the application. You can control to ignore this duplicate by setting the servlet init-parameter ignoreDuplicateServletName to true as follows: <servlet> <servlet-name>CamelServlet</servlet-name> <display-name>Camel Http Transport Servlet</display-name> <servlet-class>org.apache.camel.component.servlet.CamelHttpTransportServlet</servlet-class> <init-param> <param-name>ignoreDuplicateServletName</param-name> <param-value>true</param-value> </init-param> </servlet> But it is strongly advised to use unique servlet-name for each Camel application to avoid this duplication clash, as well any unforeseen side-effects. 301.7. Sample Note From Camel 2.7 onwards it's easier to use Servlet in Spring web applications. See Servlet Tomcat Example for details. In this sample, we define a route that exposes a HTTP service at http://localhost:8080/camel/services/hello . First, you need to publish the CamelHttpTransportServlet through the normal Web Container, or OSGi Service. Use the Web.xml file to publish the CamelHttpTransportServlet as follows: <web-app> <servlet> <servlet-name>CamelServlet</servlet-name> <display-name>Camel Http Transport Servlet</display-name> <servlet-class>org.apache.camel.component.servlet.CamelHttpTransportServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>CamelServlet</servlet-name> <url-pattern>/services/*</url-pattern> </servlet-mapping> </web-app> Then you can define your route as follows: from("servlet:hello?matchOnUriPrefix=true").process(new Processor() { public void process(Exchange exchange) throws Exception { String contentType = exchange.getIn().getHeader(Exchange.CONTENT_TYPE, String.class); String path = exchange.getIn().getHeader(Exchange.HTTP_URI, String.class); path = path.substring(path.lastIndexOf("/")); assertEquals("Get a wrong content type", CONTENT_TYPE, contentType); // assert camel http header String charsetEncoding = exchange.getIn().getHeader(Exchange.HTTP_CHARACTER_ENCODING, String.class); assertEquals("Get a wrong charset name from the message heaer", "UTF-8", charsetEncoding); // assert exchange charset assertEquals("Get a wrong charset naem from the exchange property", "UTF-8", exchange.getProperty(Exchange.CHARSET_NAME)); exchange.getOut().setHeader(Exchange.CONTENT_TYPE, contentType + "; charset=UTF-8"); exchange.getOut().setHeader("PATH", path); exchange.getOut().setBody("<b>Hello World</b>"); } }); Note Specify the relative path for camel-servlet endpoint Since we are binding the HTTP transport with a published servlet, and we don't know the servlet's application context path, the camel-servlet endpoint uses the relative path to specify the endpoint's URL. A client can access the camel-servlet endpoint through the servlet publish address: ("http://localhost:8080/camel/services") + RELATIVE_PATH("/hello") 301.7.1. Sample when using Spring 3.x See Servlet Tomcat Example . 301.7.2. Sample when using Spring 2.x When using the Servlet component in a Camel/Spring application it's often required to load the Spring ApplicationContext after the Servlet component has started. This can be accomplished by using Spring's ContextLoaderServlet instead of ContextLoaderListener . In that case you'll need to start ContextLoaderServlet after CamelHttpTransportServlet like this: <web-app> <servlet> <servlet-name>CamelServlet</servlet-name> <servlet-class> org.apache.camel.component.servlet.CamelHttpTransportServlet </servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet> <servlet-name>SpringApplicationContext</servlet-name> <servlet-class> org.springframework.web.context.ContextLoaderServlet </servlet-class> <load-on-startup>2</load-on-startup> </servlet> <web-app> 301.7.3. Sample when using OSGi From Camel 2.6.0 , you can publish the CamelHttpTransportServlet as an OSGi service with Blueprint like this: <blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://www.osgi.org/xmlns/blueprint/v1.0.0 https://www.osgi.org/xmlns/blueprint/v1.0.0/blueprint.xsd"> <bean id="camelServlet" class="org.apache.camel.component.servlet.CamelHttpTransportServlet" /> <!-- Enlist it in OSGi service registry. This will cause two things: 1) As the pax web whiteboard extender is running the CamelServlet will be registered with the OSGi HTTP Service 2) It will trigger the HttpRegistry in other bundles so the servlet is made known there too --> <service ref="camelServlet"> <interfaces> <value>javax.servlet.Servlet</value> <value>org.apache.camel.http.common.CamelServlet</value> </interfaces> <service-properties> <entry key="alias" value="/camel/services" /> <entry key="matchOnUriPrefix" value="true" /> <entry key="servlet-name" value="CamelServlet" /> </service-properties> </service> </blueprint> Then use this service in your Camel route like this: <blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0" xmlns:ext="http://aries.apache.org/blueprint/xmlns/blueprint-ext/v1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://www.osgi.org/xmlns/blueprint/v1.0.0 https://www.osgi.org/xmlns/blueprint/v1.0.0/blueprint.xsd"> <reference id="servletref" ext:proxy-method="classes" interface="org.apache.camel.http.common.CamelServlet"> <reference-listener ref="httpRegistry" bind-method="register" unbind-method="unregister" /> </reference> <bean id="httpRegistry" class="org.apache.camel.component.servlet.DefaultHttpRegistry" /> <bean id="servlet" class="org.apache.camel.component.servlet.ServletComponent"> <property name="httpRegistry" ref="httpRegistry" /> </bean> <bean id="servletProcessor" class="org.apache.camel.example.servlet.ServletProcessor" /> <camelContext xmlns="http://camel.apache.org/schema/blueprint"> <route> <!-- Notice how we can use the servlet scheme which is that reference above --> <from uri="servlet://hello" /> <process ref="servletProcessor" /> </route> </camelContext> </blueprint> For versions prior to Camel 2.6 you can use an Activator to publish the CamelHttpTransportServlet on the OSGi platform: import java.util.Dictionary; import java.util.Hashtable; import org.apache.camel.component.servlet.CamelHttpTransportServlet; import org.osgi.framework.BundleActivator; import org.osgi.framework.BundleContext; import org.osgi.framework.ServiceReference; import org.osgi.service.http.HttpContext; import org.osgi.service.http.HttpService; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.osgi.context.BundleContextAware; public final class ServletActivator implements BundleActivator, BundleContextAware { private static final Logger LOG = LoggerFactory.getLogger(ServletActivator.class); private static boolean registerService; /** * HttpService reference. */ private ServiceReference<?> httpServiceRef; /** * Called when the OSGi framework starts our bundle */ public void start(BundleContext bc) throws Exception { registerServlet(bc); } /** * Called when the OSGi framework stops our bundle */ public void stop(BundleContext bc) throws Exception { if (httpServiceRef != null) { bc.ungetService(httpServiceRef); httpServiceRef = null; } } protected void registerServlet(BundleContext bundleContext) throws Exception { httpServiceRef = bundleContext.getServiceReference(HttpService.class.getName()); if (httpServiceRef != null && !registerService) { LOG.info("Register the servlet service"); final HttpService httpService = (HttpService)bundleContext.getService(httpServiceRef); if (httpService != null) { // create a default context to share between registrations final HttpContext httpContext = httpService.createDefaultHttpContext(); // register the hello world servlet final Dictionary<String, String> initParams = new Hashtable<String, String>(); initParams.put("matchOnUriPrefix", "false"); initParams.put("servlet-name", "CamelServlet"); httpService.registerServlet("/camel/services", // alias new CamelHttpTransportServlet(), // register servlet initParams, // init params httpContext // http context ); registerService = true; } } } public void setBundleContext(BundleContext bc) { try { registerServlet(bc); } catch (Exception e) { LOG.error("Cannot register the servlet, the reason is " + e); } } } 301.7.4. Usage with Spring-Boot From Camel 2.19.0 onwards, the camel-servlet-starter library binds automatically all the rest endpoints under the /camel/* context path. The following table summarizes the additional configuration properties available in the camel-servlet-starter library. The automatic mapping of the Camel servlet can also be disabled. Spring-Boot Property Default Description camel.component.servlet.mapping.enabled true Enables the automatic mapping of the servlet component into the Spring web context camel.component.servlet.mapping.context-path /camel/* Context path used by the servlet component for automatic mapping camel.component.servlet.mapping.servlet-name CamelServlet The name of the Camel servlet 301.8. See Also Configuring Camel Component Endpoint Getting Started Servlet Tomcat Example Servlet Tomcat No Spring Example HTTP Jetty 301.9. ServletListener Component Available as of Camel 2.11 This component is used for bootstrapping Camel applications in web applications. For example beforehand people would have to find their own way of bootstrapping Camel, or rely on 3rd party frameworks such as Spring to do it. Note Sidebar This component supports Servlet 2.x onwards, which mean it works also in older web containers; which is the goal of this component. Though Servlet 2.x requires to use a web.xml file as configuration. For Servlet 3.x containers you can use annotation driven configuration to boostrap Camel using the @WebListener, and implement your own class, where you boostrap Camel. Doing this still puts the challenge how to let end users easily configure Camel, which you get for free with the old school web.xml file. Maven users will need to add the following dependency to their pom.xml for this component: <dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-servletlistener</artifactId> <version>x.x.x</version> <!-- use the same version as your Camel core version --> </dependency> 301.9.1. Using You would need to chose one of the following implementations of the abstract class org.apache.camel.component.servletlistener.CamelServletContextListener . JndiCamelServletContextListener which uses the JndiRegistry to leverage JNDI for its registry. SimpleCamelServletContextListener which uses the SimpleRegistry to leverage a java.util.Map as its registry. To use this you need to configure the org.apache.camel.component.servletlistener.CamelServletContextListener in the WEB-INF/web.xml file as shown below: 301.9.2. Options The org.apache.camel.component.servletlistener.CamelServletContextListener supports the following options which can be configured as context-param in the web.xml file. Option Type Description propertyPlaceholder.XXX To configure property placeholders in Camel. You should prefix the option with "propertyPlaceholder.", for example to configure the location, use propertyPlaceholder.location as name. You can configure all the options from the Properties component. jmx.XXX To configure JMX. You should prefix the option with "jmx.", for example to disable JMX, use jmx.disabled as name. You can configure all the options from org.apache.camel.spi.ManagementAgent . As well the options mentioned on the JMX page. name String To configure the name of the CamelContext. messageHistory Boolean Camel 2.12.2: Whether to enable or disable Message History (enabled by default). streamCache Boolean Whether to enable Stream caching. trace Boolean Whether to enable Tracer. delayer Long To set a delay value for Delay Interceptor. handleFault Boolean Whether to enable handle fault. errorHandlerRef String Refers to a context scoped Error Handler to be used. autoStartup Boolean Whether to start all routes when starting Camel. useMDCLogging Boolean Whether to use MDC logging. useBreadcrumb Boolean Whether to use breadcrumb. managementNamePattern String To set a custom naming pattern for JMX MBeans. threadNamePattern String To set a custom naming pattern for threads. properties.XXX To set custom properties on CamelContext.getProperties . This is seldom in use. routebuilder.XXX To configure routes to be used. See below for more details. CamelContextLifecycle Refers to a FQN classname of an implementation of org.apache.camel.component.servletlistener.CamelContextLifecycle . Which allows to execute custom code before and after CamelContext has been started or stopped. See below for further details. XXX To set any option on CamelContext. 301.9.3. Examples See Servlet Tomcat No Spring Example . 301.9.4. Accessing the created CamelContext Available as of Camel 2.14/2.13.3/2.12.5 The created CamelContext is stored on the ServletContext as an attribute with the key "CamelContext". You can get hold of the CamelContext if you can get hold of the ServletContext as shown below: ServletContext sc = ... CamelContext camel = (CamelContext) sc.getAttribute("CamelContext"); 301.9.5. Configuring routes You need to configure which routes to use in the web.xml file. You can do this in a number of ways, though all the parameters must be prefixed with "routeBuilder". 301.9.5.1. Using a RouteBuilder class By default Camel will assume the param-value is a FQN classname for a Camel RouteBuilder class, as shown below: <context-param> <param-name>routeBuilder-MyRoute</param-name> <param-value>org.apache.camel.component.servletlistener.MyRoute</param-value> </context-param> You can specify multiple classes in the same param-value as shown below: <context-param> <param-name>routeBuilder-routes</param-name> <!-- we can define multiple values separated by comma --> <param-value> org.apache.camel.component.servletlistener.MyRoute, org.apache.camel.component.servletlistener.routes.BarRouteBuilder </param-value> </context-param> The name of the parameter does not have a meaning at runtime. It just need to be unique and start with "routeBuilder". In the example above we have "routeBuilder-routes". But you could just as well have named it "routeBuilder.foo". 301.9.5.2. Using package scanning You can also tell Camel to use package scanning, which mean it will look in the given package for all classes of RouteBuilder types and automatic adding them as Camel routes. To do that you need to prefix the value with "packagescan:" as shown below: <context-param> <param-name>routeBuilder-MyRoute</param-name> <!-- define the routes using package scanning by prefixing with packagescan: --> <param-value>packagescan:org.apache.camel.component.servletlistener.routes</param-value> </context-param> 301.9.5.3. Using a XML file You can also define Camel routes using XML DSL, though as we are not using Spring or Blueprint the XML file can only contain Camel route(s). In the web.xml you refer to the XML file which can be from "classpath", "file" or a "http" url, as shown below: <context-param> <param-name>routeBuilder-MyRoute</param-name> <param-value>classpath:routes/myRoutes.xml</param-value> </context-param> And the XML file is: routes/myRoutes.xml <?xml version="1.0" encoding="UTF-8"?> <!-- the xmlns="http://camel.apache.org/schema/spring" is needed --> <routes xmlns="http://camel.apache.org/schema/spring"> <route id="foo"> <from uri="direct:foo"/> <to uri="mock:foo"/> </route> <route id="bar"> <from uri="direct:bar"/> <to uri="mock:bar"/> </route> </routes> Notice that in the XML file the root tag is <routes> which must use the namespace "http://camel.apache.org/schema/spring". This namespace is having the spring in the name, but that is because of historical reasons, as Spring was the first and only XML DSL back in the time. At runtime no Spring JARs is needed. Maybe in Camel 3.0 the namespace can be renamed to a generic name. 301.9.5.4. Configuring propert placeholders Here is a snippet of a web.xml configuration for setting up property placeholders to load myproperties.properties from the classpath <!-- setup property placeholder to load properties from classpath --> <!-- we do this by setting the param-name with propertyPlaceholder. as prefix and then any options such as location, cache etc --> <context-param> <param-name>propertyPlaceholder.location</param-name> <param-value>classpath:myproperties.properties</param-value> </context-param> <!-- for example to disable cache on properties component, you do --> <context-param> <param-name>propertyPlaceholder.cache</param-name> <param-value>false</param-value> </context-param> 301.9.5.5. Configuring JMX Here is a snippet of a web.xml configuration for configuring JMX, such as disabling JMX. <!-- configure JMX by using names that is prefixed with jmx. --> <!-- in this example we disable JMX --> <context-param> <param-name>jmx.disabled</param-name> <param-value>true</param-value> </context-param> JNDI or Simple as Camel Registry ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ This component uses either JNDI or Simple as the Registry. This allows you to lookup Bean s and other services in JNDI, and as well to bind and unbind your own Bean s. This is done from Java code by implementing the org.apache.camel.component.servletlistener.CamelContextLifecycle . 301.9.5.6. Using custom CamelContextLifecycle In the code below we use the callbacks beforeStart and afterStop to enlist our custom bean in the Simple Registry, and as well to cleanup when we stop. Then we need to register this class in the web.xml file as shown below, using the parameter name "CamelContextLifecycle". The value must be a FQN which refers to the class implementing the org.apache.camel.component.servletlistener.CamelContextLifecycle interface. <context-param> <param-name>CamelContextLifecycle</param-name> <param-value>org.apache.camel.component.servletlistener.MyLifecycle</param-value> </context-param> As we enlisted our HelloBean Bean using the name "myBean" we can refer to this Bean in the Camel routes as shown below: public class MyBeanRoute extends RouteBuilder { @Override public void configure() throws Exception { from("seda:foo").routeId("foo") .to("bean:myBean") .to("mock:foo"); } } Important: If you use org.apache.camel.component.servletlistener.JndiCamelServletContextListener then the CamelContextLifecycle must use the JndiRegistry as well. And likewise if the servlet is org.apache.camel.component.servletlistener.SimpleCamelServletContextListener then the CamelContextLifecycle must use the SimpleRegistry 301.9.6. See Also SERVLET Servlet Tomcat Example Servlet Tomcat No Spring Example

Commands:
<dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-servlet</artifactId> <version>x.x.x</version> <!-- use the same version as your Camel core version --> </dependency>
servlet://relative_path[?options]
servlet:contextPath
<servlet> <servlet-name>MyServlet</servlet-name> <servlet-class>org.apache.camel.component.servlet.CamelHttpTransportServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>MyServlet</servlet-name> <url-pattern>/*</url-pattern> </servlet-mapping>
<route> <from uri="servlet://foo?servletName=MyServlet"/> </route>
<servlet> <servlet-name>CamelServlet</servlet-name> <display-name>Camel Http Transport Servlet</display-name> <servlet-class>org.apache.camel.component.servlet.CamelHttpTransportServlet</servlet-class> <init-param> <param-name>ignoreDuplicateServletName</param-name> <param-value>true</param-value> </init-param> </servlet>
<web-app> <servlet> <servlet-name>CamelServlet</servlet-name> <display-name>Camel Http Transport Servlet</display-name> <servlet-class>org.apache.camel.component.servlet.CamelHttpTransportServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>CamelServlet</servlet-name> <url-pattern>/services/*</url-pattern> </servlet-mapping> </web-app>
from("servlet:hello?matchOnUriPrefix=true").process(new Processor() { public void process(Exchange exchange) throws Exception { String contentType = exchange.getIn().getHeader(Exchange.CONTENT_TYPE, String.class); String path = exchange.getIn().getHeader(Exchange.HTTP_URI, String.class); path = path.substring(path.lastIndexOf("/")); assertEquals("Get a wrong content type", CONTENT_TYPE, contentType); // assert camel http header String charsetEncoding = exchange.getIn().getHeader(Exchange.HTTP_CHARACTER_ENCODING, String.class); assertEquals("Get a wrong charset name from the message heaer", "UTF-8", charsetEncoding); // assert exchange charset assertEquals("Get a wrong charset naem from the exchange property", "UTF-8", exchange.getProperty(Exchange.CHARSET_NAME)); exchange.getOut().setHeader(Exchange.CONTENT_TYPE, contentType + "; charset=UTF-8"); exchange.getOut().setHeader("PATH", path); exchange.getOut().setBody("<b>Hello World</b>"); } });
<web-app> <servlet> <servlet-name>CamelServlet</servlet-name> <servlet-class> org.apache.camel.component.servlet.CamelHttpTransportServlet </servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet> <servlet-name>SpringApplicationContext</servlet-name> <servlet-class> org.springframework.web.context.ContextLoaderServlet </servlet-class> <load-on-startup>2</load-on-startup> </servlet> <web-app>
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://www.osgi.org/xmlns/blueprint/v1.0.0 https://www.osgi.org/xmlns/blueprint/v1.0.0/blueprint.xsd"> <bean id="camelServlet" class="org.apache.camel.component.servlet.CamelHttpTransportServlet" /> <!-- Enlist it in OSGi service registry. This will cause two things: 1) As the pax web whiteboard extender is running the CamelServlet will be registered with the OSGi HTTP Service 2) It will trigger the HttpRegistry in other bundles so the servlet is made known there too --> <service ref="camelServlet"> <interfaces> <value>javax.servlet.Servlet</value> <value>org.apache.camel.http.common.CamelServlet</value> </interfaces> <service-properties> <entry key="alias" value="/camel/services" /> <entry key="matchOnUriPrefix" value="true" /> <entry key="servlet-name" value="CamelServlet" /> </service-properties> </service> </blueprint>
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0" xmlns:ext="http://aries.apache.org/blueprint/xmlns/blueprint-ext/v1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://www.osgi.org/xmlns/blueprint/v1.0.0 https://www.osgi.org/xmlns/blueprint/v1.0.0/blueprint.xsd"> <reference id="servletref" ext:proxy-method="classes" interface="org.apache.camel.http.common.CamelServlet"> <reference-listener ref="httpRegistry" bind-method="register" unbind-method="unregister" /> </reference> <bean id="httpRegistry" class="org.apache.camel.component.servlet.DefaultHttpRegistry" /> <bean id="servlet" class="org.apache.camel.component.servlet.ServletComponent"> <property name="httpRegistry" ref="httpRegistry" /> </bean> <bean id="servletProcessor" class="org.apache.camel.example.servlet.ServletProcessor" /> <camelContext xmlns="http://camel.apache.org/schema/blueprint"> <route> <!-- Notice how we can use the servlet scheme which is that reference above --> <from uri="servlet://hello" /> <process ref="servletProcessor" /> </route> </camelContext> </blueprint>
import java.util.Dictionary; import java.util.Hashtable; import org.apache.camel.component.servlet.CamelHttpTransportServlet; import org.osgi.framework.BundleActivator; import org.osgi.framework.BundleContext; import org.osgi.framework.ServiceReference; import org.osgi.service.http.HttpContext; import org.osgi.service.http.HttpService; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.osgi.context.BundleContextAware; public final class ServletActivator implements BundleActivator, BundleContextAware { private static final Logger LOG = LoggerFactory.getLogger(ServletActivator.class); private static boolean registerService; /** * HttpService reference. */ private ServiceReference<?> httpServiceRef; /** * Called when the OSGi framework starts our bundle */ public void start(BundleContext bc) throws Exception { registerServlet(bc); } /** * Called when the OSGi framework stops our bundle */ public void stop(BundleContext bc) throws Exception { if (httpServiceRef != null) { bc.ungetService(httpServiceRef); httpServiceRef = null; } } protected void registerServlet(BundleContext bundleContext) throws Exception { httpServiceRef = bundleContext.getServiceReference(HttpService.class.getName()); if (httpServiceRef != null && !registerService) { LOG.info("Register the servlet service"); final HttpService httpService = (HttpService)bundleContext.getService(httpServiceRef); if (httpService != null) { // create a default context to share between registrations final HttpContext httpContext = httpService.createDefaultHttpContext(); // register the hello world servlet final Dictionary<String, String> initParams = new Hashtable<String, String>(); initParams.put("matchOnUriPrefix", "false"); initParams.put("servlet-name", "CamelServlet"); httpService.registerServlet("/camel/services", // alias new CamelHttpTransportServlet(), // register servlet initParams, // init params httpContext // http context ); registerService = true; } } } public void setBundleContext(BundleContext bc) { try { registerServlet(bc); } catch (Exception e) { LOG.error("Cannot register the servlet, the reason is " + e); } } }
<dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-servletlistener</artifactId> <version>x.x.x</version> <!-- use the same version as your Camel core version --> </dependency>
ServletContext sc = CamelContext camel = (CamelContext) sc.getAttribute("CamelContext");
<context-param> <param-name>routeBuilder-MyRoute</param-name> <param-value>org.apache.camel.component.servletlistener.MyRoute</param-value> </context-param>
<context-param> <param-name>routeBuilder-routes</param-name> <!-- we can define multiple values separated by comma --> <param-value> org.apache.camel.component.servletlistener.MyRoute, org.apache.camel.component.servletlistener.routes.BarRouteBuilder </param-value> </context-param>
<context-param> <param-name>routeBuilder-MyRoute</param-name> <!-- define the routes using package scanning by prefixing with packagescan: --> <param-value>packagescan:org.apache.camel.component.servletlistener.routes</param-value> </context-param>
<context-param> <param-name>routeBuilder-MyRoute</param-name> <param-value>classpath:routes/myRoutes.xml</param-value> </context-param>
<?xml version="1.0" encoding="UTF-8"?> <!-- the xmlns="http://camel.apache.org/schema/spring" is needed --> <routes xmlns="http://camel.apache.org/schema/spring"> <route id="foo"> <from uri="direct:foo"/> <to uri="mock:foo"/> </route> <route id="bar"> <from uri="direct:bar"/> <to uri="mock:bar"/> </route> </routes>
<!-- setup property placeholder to load properties from classpath --> <!-- we do this by setting the param-name with propertyPlaceholder. as prefix and then any options such as location, cache etc --> <context-param> <param-name>propertyPlaceholder.location</param-name> <param-value>classpath:myproperties.properties</param-value> </context-param> <!-- for example to disable cache on properties component, you do --> <context-param> <param-name>propertyPlaceholder.cache</param-name> <param-value>false</param-value> </context-param>
<!-- configure JMX by using names that is prefixed with jmx. --> <!-- in this example we disable JMX --> <context-param> <param-name>jmx.disabled</param-name> <param-value>true</param-value> </context-param>
<context-param> <param-name>CamelContextLifecycle</param-name> <param-value>org.apache.camel.component.servletlistener.MyLifecycle</param-value> </context-param>
public class MyBeanRoute extends RouteBuilder { @Override public void configure() throws Exception { from("seda:foo").routeId("foo") .to("bean:myBean") .to("mock:foo"); } }