How to Resolve Input resource must exist Error in Spring Batch CSV Reader

Learn how to resolve the "Input resource must exist" error while using Spring Batch CSV Reader by configuring the reader's mode for handling missing files.
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How to Resolve Input resource must exist Error in Spring Batch CSV Reader

When working with Spring Batch to process CSV files, developers may encounter the error message: Input resource must exist (reader is in 'strict' mode). This typically happens because the CSV Reader in Spring Batch is configured to require the input file to exist by default. Here's how to resolve this issue.

Understanding the Error

Spring Batch includes a feature known as 'strict' mode in its CSV file reader. The purpose of this mode is to enforce the existence of the specified input file. If the file is not found, the reader throws an error to prevent further processing. While this is a useful safeguard in many scenarios, there are situations where you might want to handle missing files more gracefully.

Solution: Adjusting the Strict Mode

To resolve the "Input resource must exist" error, you can configure the CSV Reader to operate in non-strict mode. This tells Spring Batch to proceed normally even if the input file does not exist.

Steps to Adjust Strict Mode

Open your Batch Configuration Class: Locate the class where you configure your Spring Batch job.

Locate the CSV Reader Bean: This is typically defined as a FlatFileItemReader or a derivative class.

Set Strict Mode to False: Within the CSV reader configuration, set the strict property to false.

Here is an example configuration:

[[See Video to Reveal this Text or Code Snippet]]

Verify the Adjustment

After making the above changes, Spring Batch will no longer throw an error when the specified CSV file does not exist. Instead, the job will handle the missing file according to how you've configured error handling in subsequent steps.

Additional Considerations

While disabling the strict mode can help you avoid job failures due to missing input files, it's important to consider how your application should behave in such scenarios. Ensure you handle the absence of data files in a way that fits your application's requirements.

Conclusion

By disabling the strict mode on your CSV Reader in Spring Batch, you can prevent errors related to missing input files and handle such cases more smoothly. Adjusting this setting can provide flexibility in scenarios where the presence of the input file is not guaranteed.