Spring Integration input file adapter - Where/when should file contents enter message payload?

Question

I'd started a Spring Integration project using a file-based inbound-channel-adapter and so far it's working well. But I realized that I don't seem to have implemented the concept correctly and would like to seek some advice here on how to correct it.

In the Spring XML declaration, the adapter is declared as:

<file:inbound-channel-adapter id="filesIn" directory="file:/tmp/input" prevent-duplicates="true">
    <int:poller id="poller" fixed-delay="500"/>
</file:inbound-channel-adapter>
<int:service-activator input-channel="filesIn" output-channel="filesOut" ref="fileHandler" method="handleUpdate" />
<bean id="fileHandler" class="com.myproj.integration.FileUpdater"/>
<file:outbound-channel-adapter id="filesOut" directory="file:/tmp/output" delete-source-files="true" />

In my FileUpdater class, method handleUpdate() is given an input of type File:

public File handleUpdate(File input) throws ParseException, FileNotFoundException, IOException {
    ......
}

Since I'm able to read the file using the input parameter and get all I need, I've been able to do everything that I need to in order to complete my business logic.

However, I know very well that the way I'm handling this right now (reading the File directly from file system in all my service activators) means that I am unable to change to use another inbound channel adapter (say HTTP) without impacting the code for the entire integration chain.

I reckon that the Message object passed through the integration chain should be the contents of the File itself rather than a reference to the File on the file system itself.

Question is: does Spring Integration do the work of getting the contents of the file into my Message payload? Or do I need to do some transformation to do that myself?

Gary Russell Gary Russell · Accepted Answer · 2015-05-21T09:22:30

The FileSplitterwill read a line at a time (for text-based files with lines). You will need custom code for any other file format. You can also use a file to string (or bytes) transformer if you can live with loading the whole file into memory.

See the Spring XD file source and its common import file for examples.

Spring Integration input file adapter - Where/when should file contents enter message payload?

1 Answers