FlatFileItemWriter not generating the file when using Tasklet approach

Question

I wrote the following code using tasklet approach to generate a file with data.

    public class PersonInfoFileWriter implements Tasklet {
        @Autowired
        PersonInfoFileUtil personInfoFileUtil;
    
        public void write(ExecutionContext executionContext) throws IOException {
List<PersonInfo> personInfoList = null;
            FlatFileItemWriter<PersonInfo> flatFileWriter = new FlatFileItemWriter<PersonInfo>();
flatFileWriter.setResource(new FileSystemResource("C:\\test\\"
                        + LocalDate.now().format(DateTimeFormatter.BASIC_ISO_DATE) + ".txt"));
            try {
flatFileWriter.open(executionContext);
                String personName = (String) executionContext.get("personInfo");
                //gets the details of the person by name from the database and assign the values to PersonInfo
                personInfoList  = personInfoFileUtil.setDataForPersonInfoFile(personName);
                
    
                flatFileWriter.setName("Person-Detail-File");
                flatFileWriter.setShouldDeleteIfEmpty(true);
                flatFileWriter.setAppendAllowed(true);
                flatFileWriter.setLineSeparator("\n");
                flatFileWriter.setHeaderCallback(new FlatFileHeaderCallback() {
                    @Override
                    public void writeHeader(Writer writer) throws IOException {
                        writer.write(
                                "PersonId^Name^Program^ProgramType");
                    }
                });
                flatFileWriter.setLineAggregator(new DelimitedLineAggregator<PersonInfo>() {
                    {
                        setDelimiter("^");
                        setFieldExtractor((FieldExtractor<PersonInfo>) new BeanWrapperFieldExtractor<PersonInfo>() {
                            {
                                setNames(new String[] { "personId", "name", "program", "programType" });
                            }
                        });
                    }
                });
                String lines = flatFileWriter.doWrite((List<? extends PersonInfo>) personInfoList);
                logger.info(lines); //this prints the information correctly
            } finally {
                flatFileWriter.close();
            }
            
        }
    
        @Override
        public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception {
            ExecutionContext executionContext = contribution.getStepExecution().getJobExecution().getExecutionContext();
            write(executionContext);
            return RepeatStatus.FINISHED;
        }
    }

The above code compiles and runs without errors but it is not generating any file on to the disk.

I tried debugging to check if the fileName and etc values are getting created on to a buffer to write to a disk and everything works as intended except generating and writing the data to a file.

If I write the code using chunk based approach it is working fine.

Please let me know if I am doing any mistake. Thanks for the help in advance.

EDIT: after adding the changes that were suggested the file is getting created on the disk but the file is missing out the header that I have set using setHeaderCallback()

Answer 1

In your write method, you create an instance of FlatFileItemWriter , set some properties on it and then call close on it.

You did not call open() and write() methods, that's why it is not generating an file.