For the latest stable version, please use Spring Batch Documentation 5.2.0!

Multi-File Input

It is a common requirement to process multiple files within a single Step. Assuming the files all have the same formatting, the MultiResourceItemReader supports this type of input for both XML and flat file processing. Consider the following files in a directory:

file-1.txt  file-2.txt  ignored.txt

file-1.txt and file-2.txt are formatted the same and, for business reasons, should be processed together. The MultiResourceItemReader can be used to read in both files by using wildcards.

  • Java

  • XML

The following example shows how to read files with wildcards in Java:

Java Configuration
@Bean
public MultiResourceItemReader multiResourceReader() {
	return new MultiResourceItemReaderBuilder<Foo>()
					.delegate(flatFileItemReader())
					.resources(resources())
					.build();
}

The following example shows how to read files with wildcards in XML:

XML Configuration
<bean id="multiResourceReader" class="org.spr...MultiResourceItemReader">
    <property name="resources" value="classpath:data/input/file-*.txt" />
    <property name="delegate" ref="flatFileItemReader" />
</bean>

The referenced delegate is a simple FlatFileItemReader. The above configuration reads input from both files, handling rollback and restart scenarios. It should be noted that, as with any ItemReader, adding extra input (in this case a file) could cause potential issues when restarting. It is recommended that batch jobs work with their own individual directories until completed successfully.

Input resources are ordered by using MultiResourceItemReader#setComparator(Comparator) to make sure resource ordering is preserved between job runs in restart scenario.