如何在Spring Batch中使用不同的文件名多次调用FlatFileItemReader？

Question

Goal: Have one file reader that can be called from 1 to N times, with different file names in Spring batch without have to close/reopen files every read.

What I have so far:

I roughed out the program using the following bean for reading the CSV files:

@Bean
    public ItemReader<DataLoadRecordClass> dataLoadFileItemReader() {
        this.inputRecords = new DataLoadRecordListClass();
        FlatFileItemReader<DataLoadRecordClass> reader = new FlatFileItemReader<DataLoadRecordClass>();
        reader.setEncoding("UTF-8");
        reader.setLinesToSkip(1); //skip header line
        reader.setResource(new FileSystemResource(String.format(this.fileSystemBasePath,storeName) + this.fileBasePath + this.inFileName));
        LineMapper<DataLoadRecordClass> dataFileLineMapper = buildLineMapper();
        reader.setLineMapper(dataFileLineMapper);
        return reader;
    }

StoreName and inFileName will be specified at run time, and there will normally be at least 4 stores this will need to be run for, but the requirements are for it to run for 1 to N stores.

Obviously, as the code is written it will only work for 1 store and 1 file. How can I scale this so that it can run for 1 to N stores with 1 to N files in each store, and in parallel? I do not want to create beans for each possible store and file obviously since the only difference in them will be the file name and path.

Thanks!

Answer 1

This allows me to pass in variables

@Bean
@StepScope
public FlatFileItemReader<DataLoadRecordClass> dataLoadFileItemReader(@Value("#{jobParameters['myParam']}" String storeNameEntry) {  
..etc..
}

The big catch was you can not use ItemReader for this, you have to return the FlatFileItemReader or you will get an error that it can not open the reader. This only happened with StepScope.