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

The following solution works with opencsv 5.0.

First, you need to inherit ColumnPositionMappingStrategy class and override generateHeader method to create your custom header for utilizing both CsvBindByName and CsvBindByPosition annotations as shown below.

import com.opencsv.bean.BeanField;
import com.opencsv.bean.ColumnPositionMappingStrategy;
import com.opencsv.bean.CsvBindByName;
import com.opencsv.exceptions.CsvRequiredFieldEmptyException;

/**
 * @param 
 */
class CustomMappingStrategy extends ColumnPositionMappingStrategy {
    /*
     * (non-Javadoc)
     * 
     * @see com.opencsv.bean.ColumnPositionMappingStrategy#generateHeader(java.lang.
     * Object)
     */
    @Override
    public String[] generateHeader(T bean) throws CsvRequiredFieldEmptyException {
        final int numColumns = getFieldMap().values().size();
        if (numColumns == -1) {
            return super.generateHeader(bean);
        }

        String[] header = new String[numColumns];
        super.setColumnMapping(header);

        BeanField beanField;
        for (int i = 0; i < numColumns; i++) {
            beanField = findField(i);
            String columnHeaderName = beanField.getField().getDeclaredAnnotation(CsvBindByName.class).column();
            header[i] = columnHeaderName;
        }
        return header;
    }
}

The next step is to use this mapping strategy while writing a bean to CSV as below.

CustomMappingStrategy strategy = new CustomMappingStrategy<>();
            strategy.setType(ScanReport.class);

// Write a bean to csv file.
StatefulBeanToCsv beanToCsv = new StatefulBeanToCsvBuilder(writer)
                    .withMappingStrategy(strategy).build();
beanToCsv.write(beanList);