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 works for me to map a POJO to a CSV file with custom column positioning and custom column headers (tested with opencsv-5.0) :

public class CustomBeanToCSVMappingStrategy extends ColumnPositionMappingStrategy {

    @Override
    public String[] generateHeader(T bean) throws CsvRequiredFieldEmptyException {

        String[] headersAsPerFieldName = getFieldMap().generateHeader(bean); // header name based on field name

        String[] header = new String[headersAsPerFieldName.length];

        for (int i = 0; i <= headersAsPerFieldName.length - 1; i++) {

            BeanField beanField = findField(i);

            String columnHeaderName = extractHeaderName(beanField); // header name based on @CsvBindByName annotation

            if (columnHeaderName.isEmpty()) // No @CsvBindByName is present
                columnHeaderName = headersAsPerFieldName[i]; // defaults to header name based on field name

            header[i] = columnHeaderName;
        }

        headerIndex.initializeHeaderIndex(header);

        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();
    }
}

Pojo

Column Positioning in the generated CSV file:

• The column positioing in the generated CSV file will be as per the annotation @CsvBindByPosition

Header name in the generated CSV file:

• If the field has @CsvBindByName, the generated header will be as per the annonation

• If the field doesn't have @CsvBindByName, then the generated header will be as per the field name

  @Getter @Setter @ToString
  public class Pojo {
  
      @CsvBindByName(column="Voucher Series") // header: "Voucher Series"
      @CsvBindByPosition(position=0)
      private String voucherSeries;
  
      @CsvBindByPosition(position=1) // header: "salePurchaseType"
      private String salePurchaseType;
  }
  

Using the above Custom Mapping Strategy:

CustomBeanToCSVMappingStrategy mappingStrategy = new CustomBeanToCSVMappingStrategy<>();
            mappingStrategy.setType(Pojo.class);

StatefulBeanToCsv beanToCsv = new StatefulBeanToCsvBuilder(writer)
                    .withSeparator(CSVWriter.DEFAULT_SEPARATOR)
                    .withMappingStrategy(mappingStrategy)
                    .build();

beanToCsv.write(pojoList);