How to read 2 columns from excel file (xlsx) and write it to resource properties as key=value pair

Question

I am trying to generate messages_[en/da/bg].properties file from the given set for excel (xlsx) files. Each excel sheet is provided with two columns as key-value pair. I have to read each file and write it to generate messages_en.properties file for i18n.

If I have excel sheets with filenames like locales_ENG.xlsx, locales_DAN.xlsx & locales_BGR.xlsx then it should generate files as: messages_en.properties messages_da.properties messages_bg.properties

Answer 1

I tried solving the problem by adding the Apache POI as a dependency in order to read excel file.

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>3.17</version>
</dependency>

and for writing the key-value pair I have used java Properties class.

public class App {

LinkedHashMap<String, String> map = new LinkedHashMap<>();

public static void main(String[] args) throws IOException {

    final App app = new App();

    for (final Locale locale : Locale.values()) {

        app.readExcelFile("locales_" + locale + ".xlsx");

        app.writeToPropertiesFile("messages_" + locale.name().substring(0, 2).toLowerCase() + ".properties");

    }

}

public void writeToPropertiesFile(String propertiesPath) throws IOException {

    final LinkedProperties props = new LinkedProperties();

    map.entrySet().forEach(entry -> props.setProperty(entry.getKey(), entry.getValue()));

    props.store(new FileOutputStream(new File(propertiesPath)), null);

}

public void readExcelFile(String fileName) throws IOException {

    Workbook workbook = null;

    XSSFCell cell1 = null;

    XSSFCell cell2 = null;

    try {

        workbook = WorkbookFactory.create(new File(fileName));

        final XSSFSheet sheet = (XSSFSheet) workbook.getSheetAt(0);

        final Iterator<Row> rowIterator = sheet.rowIterator();

        // skip first row which is header
        rowIterator.next();

        while (rowIterator.hasNext()) {

            final XSSFRow row = (XSSFRow) rowIterator.next();

            final Iterator<Cell> cellIterator = row.cellIterator();

            while (cellIterator.hasNext()) {

                cell1 = (XSSFCell) cellIterator.next();

                final String key = cell1.getRichStringCellValue().toString();

                if (key == "")
                    break;

                cell2 = (XSSFCell) cellIterator.next();

                final String value = cell2.getRichStringCellValue().toString();

                map.put(key, value);

            }
        }
    }

    catch (final Exception e) {

    } finally {

        if (workbook != null)

            workbook.close();
    }
}

}

In order to maintain the order of the key-value in the properties file, I have created custom properties class i.e. LinkedProperties which extends Properties class.

public class LinkedProperties extends Properties {
/**
 *
 */
private static final long serialVersionUID = 1L;

private final HashSet<Object> keys = new LinkedHashSet<>();

public LinkedProperties() {
    // Nothing is done here
}

public Iterable<Object> orderedKeys() {
    return Collections.list(keys());
}

@Override
public Enumeration<Object> keys() {
    return Collections.<Object>enumeration(keys);
}

@Override
public Object put(Object key, Object value) {
    keys.add(key);
    return super.put(key, value);
}

@Override
public synchronized boolean equals(Object o) {
    return super.equals(o);
}

@Override
public synchronized int hashCode() {
    return super.hashCode();
}

}