Spring batch FlatFileItemWriter - Showing exponential value in csv after writing it

Question

I have a Spring batch application where it reads the data from mysql database and writing the same to csv file.

Issue: Problem I'm facing when I see the data in csv, some large numbers are showing as exponential value. for example for this number '4491611100277480' it is showing as '4.49161E+15"

Below is my code snippet which i am using

// Job
@Bean
public Job databaseToCsvJob() {
    return jobBuilderFactory.get("databaseToCsvJob").incrementer(new RunIdIncrementer())
            // .listener(listener)
            .start(databaseToCsvJob_step()).build();
}

// Step
@Bean
public Step databaseToCsvJob_step() {
    return stepBuilderFactory.get("databaseToCsvJob_step").<Person, Person>chunk(1000).reader(personReader())
            .writer(personWriter()).build();
}

// Reader
@Bean
public JdbcCursorItemReader<Person> personReader() {
    JdbcCursorItemReader<Person> reader = new JdbcCursorItemReader<>();
    reader.setSql("select empCode , empName , profileName, ID from profile");
    reader.setDataSource(mysqlDataSource);
    reader.setRowMapper(personRowmapper());
    return reader;
}

// Writer
@Bean
public FlatFileItemWriter<Person> personWriter() {
    // Create writer instance
    FlatFileItemWriter<Person> writer = new FlatFileItemWriter<>();

    // Set output file location
    writer.setResource(new FileSystemResource("src/main/resources/people-data.csv"));

    // All job repetitions should "append" to same output file
    writer.setAppendAllowed(true);

    // Name field values sequence based on object properties
    writer.setLineAggregator(new DelimitedLineAggregator<Person>() {
        {
            setDelimiter(",");
            setFieldExtractor(new BeanWrapperFieldExtractor<Person>() {
                {
                    setNames(new String[] { "empCode", "empName", "profileName", "id" });
                }
            });
        }
    });
    return writer;
}

Answer 1

It happens when you use double as a data type. Change it to long and it should work fine.

If for some reason it has to remain double you can convert the value during extraction:

new BeanWrapperFieldExtractor<Person>() {
  {
    setNames(new String[] { "empCode", "empName", "profileName", "id" });
  }
  public Object[] extract(Person person) {
    return new Object[] { person.getEmpCode(), person.getEmpName(), person.getProfileName(), ((long) person.getId()) };
  }
}