Spring Batch BeanWrapperFieldExtractor for large number of fields - spring

Question

I am in process of writing a Spring Batch application that reads a CSV file, does some transforming and writes a modified CSV to be sent to another batch process.
My writer configuration looks like this:
<beans:property name="lineAggregator">
<beans:bean class="org.springframework.batch.item.file.transform.FormatterLineAggregator">
<beans:property name="fieldExtractor">
<beans:bean class="org.springframework.batch.item.file.transform.BeanWrapperFieldExtractor">
<beans:property name="names" value="column1, column2, column3, column4 ------ 322 fields " />
</beans:bean>
</beans:property>
<beans:property name="format" value="%-8s%-12s%-11s%-16s" ----322 fields />
</beans:bean>
</beans:property>
I have to write around 322 fields. I am unable to get any FormatterLineAggregator to do my work. If I write the format like
<property name="format" value="%s;%s;%s;%s;%s;%s;%s;%f;%f;%s;%f;%f;%td.%tm.%​tY;%td.%tm.%<‌​tY;%s;%td.%tm.%&‌​lt;tY;%s;%s;%s;%s;%t‌​d.%tm.%tY" /> ,
its getting really messy and its tough to make sure all fields are correct.
I thought of 3 different solutions:
Either go with the approach above.
Write a CustomEditorFieldsExtractor but don't know what to write in the class and how to format the fields (preferred).
Use a "non-standard" BeanIO framework jar but I fear my client won't agree to this solution.
Can someone please provide some inputs. Appreciate your help!

Answer 1

You can proceed with solution #2 in this way:
Externalize how to format every property of you bean class (eg, in XML or text file)
Write a custom LineAggregator and make it works coupled with directive at point 1
class Aggregator implements LineAggregator<T> {
private Map<String, String> propertyFormat;
public String aggregate(T item) {
final StringBuilder sb = new StringBuilder();
for(final String property : propertyFormat.keySet()) {
final String format = propertyFormat.get(property);
final Object propertyValue = /* Extract property from item using Spring beans */;
sb.append(String.format(format, propertyValue));
}
return sb.toString();
}
}