Chapter 60. Spring Batch
Since Camel 2.10
Only producer is supported
The Spring Batch component and support classes provide integration bridge between Camel and Spring Batch infrastructure.
Maven users must add the following dependency to their pom.xml
for this component:
<dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-spring-batch</artifactId> <version>x.x.x</version> <!-- use the same version as your Camel core version --> </dependency>
60.1. URI format
spring-batch:jobName[?options]
jobName
represents the name of the Spring Batch job located in the Camel registry. If a JobRegistry is provided is used to locate the job.
This component is only used to define producer endpoints, that means you cannot use the Spring Batch component in a from()
statement.
60.2. Configuring Options
Camel components are configured on two levels:
- Component level
- Endpoint level
60.2.1. Component Level Options
The component level is the highest level. The configurations you define at this level are inherited by all the endpoints. For example, a component can have security settings, credentials for authentication, urls for network connection, and so on.
Since components typically have pre-configured defaults for the most common cases, you may need to only configure a few component options, or maybe none at all.
You can configure components with Component DSL in a configuration file (application.properties|yaml), or directly with Java code.
60.2.2. Endpoint Level Options
At the Endpoint level you have many options, which you can use to configure what you want the endpoint to do. The options are categorized according to whether the endpoint is used as a consumer (from) or as a producer (to) or used for both.
You can configure endpoints directly in the endpoint URI as path
and query
parameters. You can also use Endpoint DSL and DataFormat DSL as type safe ways of configuring endpoints and data formats in Java.
When configuring options, use Property Placeholders for urls, port numbers, sensitive information, and other settings.
Placeholders allows you to externalize the configuration from your code, giving you more flexible and reusable code.
60.3. Component Options
The Spring Batch component supports 4 options, which are listed below.
Name | Description | Default | Type |
---|---|---|---|
jobLauncher (producer) | Explicitly specifies a JobLauncher to be used. | JobLauncher | |
jobRegistry (producer) | Explicitly specifies a JobRegistry to be used. | JobRegistry | |
lazyStartProducer (producer) | Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. | false | boolean |
autowiredEnabled (advanced) | Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc. | true | boolean |
60.4. Endpoint Options
The Spring Batch endpoint is configured using URI syntax:
spring-batch:jobName
Following are the path and query parameters:
60.4.1. Path Parameters (1 parameters)
Name | Description | Default | Type |
---|---|---|---|
jobName (producer) | Required The name of the Spring Batch job located in the registry. | String |
60.4.2. Query Parameters (4 parameters)
Name | Description | Default | Type |
---|---|---|---|
jobFromHeader (producer) | Explicitly defines if the jobName should be taken from the headers instead of the URI. | false | boolean |
jobLauncher (producer) | Explicitly specifies a JobLauncher to be used. | JobLauncher | |
jobRegistry (producer) | Explicitly specifies a JobRegistry to be used. | JobRegistry | |
lazyStartProducer (producer (advanced)) | Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. | false | boolean |
60.5. Usage
When Spring Batch component receives the message, it triggers the job execution. The job is executed using the org.springframework.batch.core.launch.JobLaucher
instance resolved according to the following algorithm.
-
if
JobLauncher
is manually set on the component, then use it. -
if
jobLauncherRef
option is set on the component, then search Camel Registry for theJobLauncher
with the given name. -
if there is
JobLauncher
registered in the Camel Registry under jobLauncher name, then use it. -
if none of the steps above allow to resolve the
JobLauncher
and there is exactly oneJobLauncher
instance in the Camel Registry, then use it.
All headers found in the message are passed to the JobLauncher
as job parameters. String
, Long
, Double
and java.util.Date
values are copied to the org.springframework.batch.core.JobParametersBuilder
and other data types are converted to Strings.
60.6. Examples
Triggering the Spring Batch job execution:
from("direct:startBatch").to("spring-batch:myJob");
Triggering the Spring Batch job execution with the JobLauncher
set explicitly.
from("direct:startBatch").to("spring-batch:myJob?jobLauncherRef=myJobLauncher");
A JobExecution
instance returned by the JobLauncher
is forwarded by the SpringBatchProducer
as the output message. You can use the JobExecution
instance to perform some operations using the Spring Batch API directly.
from("direct:startBatch").to("spring-batch:myJob").to("mock:JobExecutions"); ... MockEndpoint mockEndpoint = ...; JobExecution jobExecution = mockEndpoint.getExchanges().get(0).getIn().getBody(JobExecution.class); BatchStatus currentJobStatus = jobExecution.getStatus();
60.7. Support classes
Apart from the component, Camel Spring Batch also provides support classes that you can use to hook into Spring Batch infrastructure.
60.7.1. CamelItemReader
CamelItemReader
can be used to read batch data directly from the Camel infrastructure.
For example, the snippet below configures Spring Batch to read data from JMS queue:
<bean id="camelReader" class="org.apache.camel.component.spring.batch.support.CamelItemReader"> <constructor-arg ref="consumerTemplate"/> <constructor-arg value="jms:dataQueue"/> </bean> <batch:job id="myJob"> <batch:step id="step"> <batch:tasklet> <batch:chunk reader="camelReader" writer="someWriter" commit-interval="100"/> </batch:tasklet> </batch:step> </batch:job>
60.7.2. CamelItemWriter
CamelItemWriter
has similar purpose as CamelItemReader
, but it is dedicated to write chunk of the processed data.
For example the snippet below configures Spring Batch to read data from JMS queue.
<bean id="camelwriter" class="org.apache.camel.component.spring.batch.support.CamelItemWriter"> <constructor-arg ref="producerTemplate"/> <constructor-arg value="jms:dataQueue"/> </bean> <batch:job id="myJob"> <batch:step id="step"> <batch:tasklet> <batch:chunk reader="someReader" writer="camelwriter" commit-interval="100"/> </batch:tasklet> </batch:step> </batch:job>
60.7.3. CamelItemProcessor
CamelItemProcessor
is the implementation of Spring Batch org.springframework.batch.item.ItemProcessor
interface. The latter implementation relays on Request Reply pattern to delegate the processing of the batch item to the Camel infrastructure. The item to process is sent to the Camel endpoint as the body of the message.
For example the snippet below performs simple processing of the batch item using the Direct endpoint and the Simple expression language.
<camel:camelContext> <camel:route> <camel:from uri="direct:processor"/> <camel:setExchangePattern pattern="InOut"/> <camel:setBody> <camel:simple>Processed ${body}</camel:simple> </camel:setBody> </camel:route> </camel:camelContext> <bean id="camelProcessor" class="org.apache.camel.component.spring.batch.support.CamelItemProcessor"> <constructor-arg ref="producerTemplate"/> <constructor-arg value="direct:processor"/> </bean> <batch:job id="myJob"> <batch:step id="step"> <batch:tasklet> <batch:chunk reader="someReader" writer="someWriter" processor="camelProcessor" commit-interval="100"/> </batch:tasklet> </batch:step> </batch:job>
60.7.4. CamelJobExecutionListener
CamelJobExecutionListener
is the implementation of the org.springframework.batch.core.JobExecutionListener
interface sending job execution events to the Camel endpoint.
The org.springframework.batch.core.JobExecution
instance produced by the Spring Batch is sent as a body of the message. To distinguish between before- and after-callbacks SPRING_BATCH_JOB_EVENT_TYPE
header is set to the BEFORE
or AFTER
value.
The example snippet below sends Spring Batch job execution events to the JMS queue.
<bean id="camelJobExecutionListener" class="org.apache.camel.component.spring.batch.support.CamelJobExecutionListener"> <constructor-arg ref="producerTemplate"/> <constructor-arg value="jms:batchEventsBus"/> </bean> <batch:job id="myJob"> <batch:step id="step"> <batch:tasklet> <batch:chunk reader="someReader" writer="someWriter" commit-interval="100"/> </batch:tasklet> </batch:step> <batch:listeners> <batch:listener ref="camelJobExecutionListener"/> </batch:listeners> </batch:job>
60.8. Spring Boot Auto-Configuration
When using spring-batch
with Spring Boot, use the following Maven dependency to enable support for auto-configuration:
<dependency> <groupId>org.apache.camel.springboot</groupId> <artifactId>camel-spring-batch-starter</artifactId> <version>x.x.x</version> <!-- use the same version as your Camel core version --> </dependency>
The component supports 5 options, which are listed below.
Name | Description | Default | Type |
---|---|---|---|
camel.component.spring-batch.autowired-enabled | Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc. | true | Boolean |
camel.component.spring-batch.enabled | Whether to enable auto-configuration of the spring-batch component. This is enabled by default. | Boolean | |
camel.component.spring-batch.job-launcher | Explicitly specifies a JobLauncher to be used. The option is a org.springframework.batch.core.launch.JobLauncher type. | JobLauncher | |
camel.component.spring-batch.job-registry | Explicitly specifies a JobRegistry to be used. The option is a org.springframework.batch.core.configuration.JobRegistry type. | JobRegistry | |
camel.component.spring-batch.lazy-start-producer | Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing. | false | Boolean |