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Maven users will need to add the following dependency to their pom.xml for this component:
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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
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caching or convert the message body to a String which is safe to be read multiple times.
URI format
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You can append query options to the URI in the following format, ?option=value&option=value&...
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Name | Default Value | Description |
|---|---|---|
|
| Reference to an |
httpBinding | null | Camel 2.16: Reference to an org.apache.camel.component.http.HttpBinding in the Registry. A HttpBinding implementation can be used to customize how to write a response. |
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| Whether or not the |
|
| Specifies the servlet name that the servlet endpoint will bind to. This name should match the name you define in |
| null | Camel 2.11: Consumer only: Used to only allow consuming if the HttpMethod matches, such as GET/POST/PUT etc. From Camel 2.15 onwards multiple methods can be specified separated by comma. |
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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
Using Servlet 3.0 Async Mode
Available as of Camel 2.18
You can configure the servlet with an init-param to turn on async mode when using a Servlet 3.x container. There is a sample XML configuration below:
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Putting Camel JARs in the app server boot classpath
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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:
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And in your Camel endpoints then include the servlet name as well
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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:
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But its strongly advised to use unique servlet-name for each Camel application to avoid this duplication clash, as well any unforeseen side-effects.
Sample
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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:
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Then you can define your route as follows:
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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").
Sample when using Spring 3.x
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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:
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Sample when using OSGi
From Camel 2.6.0, you can publish the CamelHttpTransportServlet as an OSGi service with help of SpringDM like this.
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Then use this service in your camel route like this:
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For versions prior to Camel 2.6 you can use an Activator to publish the CamelHttpTransportServlet on the OSGi platform
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