Opencsv convertion bean enums to csv

Question

I would like to write a csv file from a bean with enums. My bean contains:

@NotNull(message = "userRole should not be blank")
private UserRole userRole;

UserRole class:

@Getter
@RequiredArgsConstructor
public enum UserRole {
    STUDENT("student"),
    TEACHER("teacher");

    private final String value;
}

Building csv file looks like that:

private <T extends CsvBean> String writeCsvFromBean(Path ddir, String fileName, List<T> obj) throws IOException, CsvDataTypeMismatchException, CsvRequiredFieldEmptyException {
    String filePath = ddir.resolve(fileName).toString();
    try (Writer writer  = new FileWriter(filePath)) {
        StatefulBeanToCsv<T> sbc = new StatefulBeanToCsvBuilder<T>(writer)
        .withSeparator(ICSVWriter.DEFAULT_SEPARATOR)
        .build();

        sbc.write(obj);
    }
    return filePath;
}

In the resulted csv file I can see the enum values listed as STUDENT/TEACHER (capital letters) instead of enum's valueOf results student/teacher. How to force opencsv to generate csv based on enum valueOf?

BR

Answer 1

By default enum conversion is using name() of the enum, referring to ConverterEnum. You may override this conversion using CsvCustomBindByName and create a custom converter.

import com.opencsv.bean.CsvCustomBindByName;
import lombok.Getter;
import lombok.Setter;

@Getter
@Setter
public class CsvBean {
    @CsvCustomBindByName(converter = UserRoleConverter.class)
    private UserRole userRole;
}

import com.opencsv.bean.AbstractBeanField;

import java.util.Arrays;

public class UserRoleConverter extends AbstractBeanField<UserRole, String> {
    // for reading back from csv to bean
    @Override
    protected Object convert(String value) {
        return Arrays.stream(UserRole.values())
                .filter(userRole -> userRole.getValue().equals(value))
                .findFirst().orElse(null);
    }

    @Override
    protected String convertToWrite(Object value) {
        if (value == null) {
            return "";
        }
        return ((UserRole) value).getValue();
    }
}