Java - Write hashmap to a csv file

Question

I have a hashmap with a String key and String value. It contains a large number of keys and their respective values.

For example:

key | value
abc | a         


        

Answer 1

Using the Jackson API, Map or List of Map could be written in CSV file. See complete example here

 /**
 * @param listOfMap
 * @param writer
 * @throws IOException
 */
public static void csvWriter(List> listOfMap, Writer writer) throws IOException {
    CsvSchema schema = null;
    CsvSchema.Builder schemaBuilder = CsvSchema.builder();
    if (listOfMap != null && !listOfMap.isEmpty()) {
        for (String col : listOfMap.get(0).keySet()) {
            schemaBuilder.addColumn(col);
        }
        schema = schemaBuilder.build().withLineSeparator(System.lineSeparator()).withHeader();
    }
    CsvMapper mapper = new CsvMapper();
    mapper.writer(schema).writeValues(writer).writeAll(listOfMap);
    writer.flush();
}