How to create a generic FlatFileItemReader to read CSV files with different headers?

Question

I\'m creating a job that will read and process different .csv files based on an input parameter. There are 3 different types of .csv files with different headers. I want to

Answer 1

You wrote:

A tasklet will first read the input parameter to decide which file type needs to be read.

Because the tasklet or infoHolder knows about type of file you can implement the creation of specific FieldSetMapper instance.

This is a demo example how it can be implemented:

public class Solution {
    private InfoHolder infoHolder = new InfoHolder();

    @Bean
    public FlatFileItemReader reader()
    {
        FlatFileItemReader reader = new FlatFileItemReader();
        reader.setLinesToSkip(1);

        reader.setLineMapper(new DefaultLineMapper() {
            {
                setLineTokenizer(infoHolder.getLineTokenizer());
                setFieldSetMapper(infoHolder.getFieldSetMapper());
            }
        });
        return reader;
    }

    private class InfoHolder {
        DelimitedLineTokenizer getLineTokenizer() {
            return ;
        }

        FieldSetMapper getFieldSetMapper() {
            if (some condition for specific file POJO 1){
                return new BeanWrapperFieldSetMapper() {
                    {
                        setTargetType(FileSpecificPOJO_1.class);
                    }
                };
            } else if (some condition for specific file POJO 2){
                return new BeanWrapperFieldSetMapper() {
                    {
                        setTargetType(FileSpecificPOJO_2.class);
                    }
                };
            }
        }
    }
}