OpenCSV: How to create CSV file from POJO with custom column headers and custom column positions?

Question

I have created a MappingsBean class where all the columns of the CSV file are specified. Next I parse XML files and create a list of mappingbeans. Then I write that data int

Answer 1

In the latest version the solution of @Sebast26 does no longer work. However the basic is still very good. Here is a working solution with v5.0

import com.opencsv.bean.BeanField;
import com.opencsv.bean.ColumnPositionMappingStrategy;
import com.opencsv.bean.CsvBindByName;
import com.opencsv.exceptions.CsvRequiredFieldEmptyException;
import org.apache.commons.lang3.StringUtils;

class CustomMappingStrategy extends ColumnPositionMappingStrategy {
    @Override
    public String[] generateHeader(T bean) throws CsvRequiredFieldEmptyException {
        final int numColumns = getFieldMap().values().size();
        super.generateHeader(bean);

        String[] header = new String[numColumns];

        BeanField beanField;
        for (int i = 0; i < numColumns; i++) {
            beanField = findField(i);
            String columnHeaderName = extractHeaderName(beanField);
            header[i] = columnHeaderName;
        }
        return header;
    }

    private String extractHeaderName(final BeanField beanField) {
        if (beanField == null || beanField.getField() == null || beanField.getField().getDeclaredAnnotationsByType(
                CsvBindByName.class).length == 0) {
            return StringUtils.EMPTY;
        }

        final CsvBindByName bindByNameAnnotation = beanField.getField().getDeclaredAnnotationsByType(CsvBindByName.class)[0];
        return bindByNameAnnotation.column();
    }
}

And the model looks like this:

@CsvBindByName(column = "id")
@CsvBindByPosition(position = 0)
private Long id;
@CsvBindByName(column = "name")
@CsvBindByPosition(position = 1)
private String name;

And my generation helper looks something like this:

public static  String createCsv(List data, Class beanClazz) {
    CustomMappingStrategy mappingStrategy = new CustomMappingStrategy();
    mappingStrategy.setType(beanClazz);

    StringWriter writer = new StringWriter();
    String csv = "";
    try {
        StatefulBeanToCsv sbc = new StatefulBeanToCsvBuilder(writer)
                .withSeparator(';')
                .withMappingStrategy(mappingStrategy)
                .build();
        sbc.write(data);
        csv = writer.toString();
    } catch (CsvRequiredFieldEmptyException e) {
        // TODO add some logging...
    } catch (CsvDataTypeMismatchException e) {
        // TODO add some logging...
    } finally {
        try {
            writer.close();
        } catch (IOException e) {
        }
    }
    return csv;
}