OpenCSV - How to map selected columns to Java Bean regardless of order?

Question

I have a CSV file with the following columns: id, fname, telephone, lname, address.

I have a P

Answer 1

Use uniVocity-parsers and be done with it. It doesn't matter how the columns are organized in the input CSV, only the ones you need will be parsed.

If writing, the columns you have in class will be written to the correct columns, while the others will be empty.

Here's a class with some examples:

class TestBean {

    // if the value parsed in the quantity column is "?" or "-", it will be replaced by null.
    @NullString(nulls = { "?", "-" })
    // if a value resolves to null, it will be converted to the String "0".
    @Parsed(defaultNullRead = "0")
    private Integer quantity;   // The attribute type defines which conversion will be executed when processing the value.

    @Trim
    @LowerCase
    // the value for the comments attribute is in the column at index 4 (0 is the first column, so this means fifth column in the file)
    @Parsed(index = 4)
    private String comments;

    // you can also explicitly give the name of a column in the file.
    @Parsed(field = "amount")
    private BigDecimal amount;

    @Trim
    @LowerCase
    // values "no", "n" and "null" will be converted to false; values "yes" and "y" will be converted to true
    @BooleanString(falseStrings = { "no", "n", "null" }, trueStrings = { "yes", "y" })
    @Parsed
    private Boolean pending;
}

Here's how to get a list of TestBean

BeanListProcessor rowProcessor = new BeanListProcessor(TestBean.class);

CsvParserSettings parserSettings = new CsvParserSettings();
parserSettings.setRowProcessor(rowProcessor);
parserSettings.setHeaderExtractionEnabled(true);

CsvParser parser = new CsvParser(parserSettings);
parser.parse(getReader("/examples/bean_test.csv"));

List beans = rowProcessor.getBeans();

Disclosure: I am the author of this library. It's open-source and free (Apache V2.0 license).