For the latest stable version, please use Spring Batch Documentation 5.2.0! |
Controlling Rollback
By default, regardless of retry or skip, any exceptions thrown from the ItemWriter
cause the transaction controlled by the Step
to rollback. If skip is configured as
described earlier, exceptions thrown from the ItemReader
do not cause a rollback.
However, there are many scenarios in which exceptions thrown from the ItemWriter
should
not cause a rollback, because no action has taken place to invalidate the transaction.
For this reason, you can configure the Step
with a list of exceptions that should not
cause rollback.
-
Java
-
XML
In Java, you can control rollback as follows:
@Bean
public Step step1(JobRepository jobRepository, PlatformTransactionManager transactionManager) {
return new StepBuilder("step1", jobRepository)
.<String, String>chunk(2, transactionManager)
.reader(itemReader())
.writer(itemWriter())
.faultTolerant()
.noRollback(ValidationException.class)
.build();
}
In XML, you can control rollback as follows:
<step id="step1">
<tasklet>
<chunk reader="itemReader" writer="itemWriter" commit-interval="2"/>
<no-rollback-exception-classes>
<include class="org.springframework.batch.item.validator.ValidationException"/>
</no-rollback-exception-classes>
</tasklet>
</step>
Transactional Readers
The basic contract of the ItemReader
is that it is forward-only. The step buffers
reader input so that, in case of a rollback, the items do not need to be re-read
from the reader. However, there are certain scenarios in which the reader is built on
top of a transactional resource, such as a JMS queue. In this case, since the queue is
tied to the transaction that is rolled back, the messages that have been pulled from the
queue are put back on. For this reason, you can configure the step to not buffer the
items.
-
Java
-
XML
The following example shows how to create a reader that does not buffer items in Java:
@Bean
public Step step1(JobRepository jobRepository, PlatformTransactionManager transactionManager) {
return new StepBuilder("step1", jobRepository)
.<String, String>chunk(2, transactionManager)
.reader(itemReader())
.writer(itemWriter())
.readerIsTransactionalQueue()
.build();
}
The following example shows how to create a reader that does not buffer items in XML:
<step id="step1">
<tasklet>
<chunk reader="itemReader" writer="itemWriter" commit-interval="2"
is-reader-transactional-queue="true"/>
</tasklet>
</step>