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Maven users will need to add the following dependency to their pom.xml
in order to use this component:
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<dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-spring-boot</artifactId> <version>${camel.version}</version> <!-- use the same version as your Camel core version --> </dependency> |
camel-spring-boot
jar comes with the spring.factories
file, so as soon as you add that dependency into your classpath, Spring Boot will automatically auto-configure Camel for you.
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To use the starter, add the following to your spring boot boot pom.xml
file:
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<dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-spring-boot-starter</artifactId> <version>2.17.0</version> </dependency> |
Then you can just add classes with your Camel routes such as:
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package com.example; import org.apache.camel.builder.RouteBuilder; import org.springframework.stereotype.Component; @Component public class MyRoute extends RouteBuilder { @Override public void configure() throws Exception { from("timer:foo").to("log:bar"); } } |
Then these routes will be started automatically. To keep the main thread blocked so that Camel stays up, either include the spring-boot-starter-web
dependency, or add cameladd camel.springboot.main-run-controller=true
to your application.properties
or application.yml
file.
You can further customize the Camel application in the application.properties
or application.yml
file with camel.springboot.* properties
.
Auto-
...
Configured Camel
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Context
The most important piece of functionality provided by the Camel auto-configuration is CamelContext
instance. Camel auto-configuration creates a SpringCamelContext
for you and takes care of the proper initialization and shutdown of that context. The created Camel context is also registered in the Spring application context (under camelContext
bean name), so you can access it just as any other Spring bean.
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@Configuration public class MyAppConfig { @Autowired CamelContext camelContext; @Bean MyService myService() { return new DefaultMyService(camelContext); } } |
Auto-
...
Detecting Camel
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Routes
Camel auto-configuration collects all the RouteBuilder
instances from the Spring context and automatically injects them into the provided CamelContext
. That means that creating new Camel route with the Spring Boot starter is as simple as adding the @Component
annotated class to your classpath:
...
...or creating a new route RouteBuilder
bean in your @Configuration
class:
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@Configuration public class MyRouterConfiguration { @Bean RoutesBuilder myRouter() { return new RouteBuilder() { @Override public void configure() throws Exception { from("jms:invoices") .to("file:/invoices"); } }; } } |
Camel properties
Spring Boot auto-configuration automatically connects to Spring Boot external configuration (like properties placeholders, OS environment variables or system properties) with the Camel properties support. It basically means that any property defined in application.properties
file:
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route.from = jms:invoices |
...
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@Component public class MyRouter extends RouteBuilder { @Override public void configure() throws Exception { from("{{route.from}}") .to("{{route.to}}"); } } |
Custom Camel
...
Context Configuration
If you would like to perform some operations on CamelContext
bean created by Camel auto-configuration, register CamelContextConfiguration
instance in your Spring context:
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@Configuration public class MyAppConfig { ... @Bean CamelContextConfiguration contextConfiguration() { return new CamelContextConfiguration() { @Override void beforeApplicationStart(CamelContext context) { // your custom configuration goes here } }; } } |
Method CamelContextConfiguration#
beforeApplicationStart(CamelContext)
will be called just before the Spring context is started, so the CamelContext
instance passed to this callback is fully auto-configured. You can add many instances of CamelContextConfiguration
CamelContextConfiguration
into your Spring context - all of them will be executed.
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To disable JMX of the auto-configured CamelContext
use camel.springboot.jmxEnabled
property (JMX is enabled by default). For example you could add the following property to your application.properties
file:
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camel.springboot.jmxEnabled = false |
Auto-
...
Configured Consumer and Producer Templates
Camel auto-configuration provides pre-configured ConsumerTemplate
and ProducerTemplate
instances. You can simply inject them into your Spring-managed beans:
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By default consumer templates and producer templates come with the endpoint cache sizes set to 1000
. You can change those values via the following Spring properties:
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camel.springboot.consumerTemplateCacheSize = 100 camel.springboot.producerTemplateCacheSize = 200 |
Auto-
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Configured TypeConverter
Camel auto-configuration registers a TypeConverter
instance named typeConverter
in the Spring context.
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@Component
public class InvoiceProcessor {
@Autowired
private TypeConverter typeConverter;
public long parseInvoiceValue(Invoice invoice) {
String invoiceValue = invoice.grossValue();
return typeConverter.convertTo(Long.class, invoiceValue);
}
} |
Spring
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Type Conversion API
...
Bridge
Spring comes with the powerful type conversion API. Spring API happens to be very similar to the Camel type converter API. As those APIs are so similar, Camel Spring Boot automatically registers a bridge converter (SpringTypeConverter
) that delegates to the Spring conversion API.That means that out-of-the-box Camel will treat Spring Converters like Camel ones. With this approach you can enjoy both Camel and Spring converters accessed via Camel TypeConverter
API:
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| ||
@Component
public class InvoiceProcessor {
@Autowired
private TypeConverter typeConverter;
public UUID parseInvoiceId(Invoice invoice) {
// Using Spring's StringToUUIDConverter
UUID id = invoice.typeConverter.convertTo(UUID.class, invoice.getId());
}
} |
Under the hood Camel Spring Boot delegates conversion to the Spring's ConversionService
instances available in the application context. If no ConversionService
instance is available, Camel Spring Boot auto-configuration will create one for you.
Disabling
...
Type Conversions Features
If you don't want Camel Spring Boot to register type-conversions related features (like TypeConverter
instance or Spring bridge) set the camel.springboot.typeConversion
property to false
.
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| ||||
camel.springboot.typeConversion = false |
Fat
...
Jars and
...
Fat Wars
The easiest way to create a Camel-aware Spring Boot fat jar/war is to extend the org.apache.camel.spring.boot.F
class...:atJarRouter
Code Block | ||
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| ||
package com.example;
... // imports
@SpringBootApplication
public class MyFatJarRouter extends FatJarRouter {
@Override
public void configure() throws Exception {
from("netty-http:http://0.0.0.0:18080").
setBody().simple("ref:helloWorld");
}
@Bean
String helloWorld() {
return "helloWorld";
}
} |
...and add the following property to your application.properties
file:
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spring.main.sources = com.example.MyFatJarRouter |
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In order to turn your fat jar into fat war, add the following class extending org.apache.camel.spring.boot.F
to your project:atWarInitializer
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| ||
package com.example; ... // imports public class MyFatJarRouterWarInitializer extends FatWarInitializer { @Override protected Class<? extends FatJarRouter> routerClass() { return MyFatJarRouter.class; } } |
Blocking
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Main Thread
This feature is available starting from Camel 2.15.2. Camel applications extending FatJarRouter by default block the main thread of the application. It means that after you start your fat jar, your application waits for for Ctrl+C
signal and does not exit immediately. If you would like to achieve similar behavior for non-FatJarRouter
applications, retrieve CamelSpringBootApplicationController
bean from your ApplicationContext
and use the former to block the main thread of your application using CamelSpringBootApplicationController#blockMainThread()
method.
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public static void main(String... args) { ApplicationContext applicationContext = new SpringApplication(MyCamelApplication.class).run(args); CamelSpringBootApplicationController applicationController = applicationContext.getBean(CamelSpringBootApplicationController.class); applicationController.blockMainThread(); } |
Adding XML
...
Routes
By default you can put Camel XML routes in the classpath under the directory camel, which camel-spring-boot will auto detect and include. From Camel 2.17 onwards : you can configure the directory name or turn this off using the configuration option:
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// turn off camel.springboot.xmlRoutes = false // scan in the com/foo/routes classpath camel.springboot.xmlRoutes = classpath:com/foo/routes/*.xml |
...
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| ||||
<routes xmlns="http://camel.apache.org/schema/spring"> <route id="test"> <from uri="timer://trigger"/> <transform> <simple>ref:myBean</simple> </transform> <to uri="log:out"/> </route> </routes> |
Adding
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Rest-
...
DSL
Available since Camel 2.18
By default you can put Camel Rest-DSL XML routes in the classpath under the directory camel-rest
, which camel-spring-boot which will auto detect and include.
You can configure the directory name or turn this off using the configuration optioncamel-spring-boot
Code Block |
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// turn off camel.springboot.xmlRests = false // scan in the com/foo/routes classpath camel.springboot.xmlRests = classpath:com/foo/rests/*.xml |
...