Spring Batch: Writing data to multiple files with dynamic File Name

Question

I have a requirement to get the data from a database and write that data to files based on the filename given in the database.

This is how data is defined in the da

Answer 1

I'm not sure but I don't think there is an easy way of obtaining this. You could try to build your own ItemWriter like this:

public class DynamicItemWriter  implements ItemStream, ItemWriter {

    private Map> writers = new HashMap<>();

    private LineAggregator lineAggregator;

    private ExecutionContext executionContext;

    @Override
    public void open(ExecutionContext executionContext) throws ItemStreamException {
        this.executionContext = executionContext;
    }

    @Override
    public void update(ExecutionContext executionContext) throws ItemStreamException {
    }

    @Override
    public void close() throws ItemStreamException {
        for(FlatFileItemWriter f:writers.values()){
            f.close();
        }
    }

    @Override
    public void write(List items) throws Exception {
        for (YourEntry item : items) {
            FlatFileItemWriter ffiw = getFlatFileItemWriter(item);
            ffiw.write(Arrays.asList(item));
        }
    }

    public LineAggregator getLineAggregator() {
        return lineAggregator;
    }

    public void setLineAggregator(LineAggregator lineAggregator) {
        this.lineAggregator = lineAggregator;
    }


    public FlatFileItemWriter getFlatFileItemWriter(YourEntry item) {
        String key = item.FileName();
        FlatFileItemWriter rr = writers.get(key);
        if(rr == null){
            rr = new FlatFileItemWriter<>();
            rr.setLineAggregator(lineAggregator);
            try {
                UrlResource resource = new UrlResource("file:"+key);
                rr.setResource(resource);
                rr.open(executionContext);
            } catch (MalformedURLException e) {
                e.printStackTrace();
            }
            writers.put(key, rr);
            //rr.afterPropertiesSet();
        }
        return rr;
    }
}

and configure it as a writer: