ApchePoiExcel Custom Encoding

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;

import java.io.ByteArrayOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;

/**
 * Add this to your pom for apache poi
 *
 *      <!-- https://mvnrepository.com/artifact/org.apache.poi/poi -->
 *      <dependency>
 *          <groupId>org.apache.poi</groupId>
 *          <artifactId>poi</artifactId>
 *          <version>4.0.0</version>
 *      </dependency>
 *
 *      ONly if you need ".xlsX"
 *      <!-- https://mvnrepository.com/artifact/org.apache.poi/poi-ooxml -->
 *      <dependency>
 *          <groupId>org.apache.poi</groupId>
 *          <artifactId>poi-ooxml</artifactId>
 *          <version>4.0.0</version>
 *      </dependency>
 *
 */
public class ExcelEncoding {

    public static void main(String[] args) throws Exception {
        ApachePoiExcelEncoding excel1Encoded = new ApachePoiExcelEncoding("sheet 1");
        excel1Encoded.writeData();
        excel1Encoded.save("encoded_sheet_iso_8859-15_latin_9");

        ApachePoiExcelEncoding excel2Encoded = new ApachePoiExcelEncoding("sheet test 2", StandardCharsets.ISO_8859_1.name());
        excel2Encoded.writeData();
        excel2Encoded.save("encoded_sheet_ISO-8859-1");
    }

    /**
     * Write an excel with a custom encoding
     */
    static class ApachePoiExcelEncoding {
        private String encoding = "ISO-8859-15";
        private Workbook wb;
        private Sheet sheet;

        ApachePoiExcelEncoding(String sheetName) {
            wb = new HSSFWorkbook();
            sheet = wb.createSheet(sheetName);
        }

        public ApachePoiExcelEncoding(String sheetName, String encoding) {
            this.wb = new HSSFWorkbook();
            this.sheet = wb.createSheet(sheetName);
            this.encoding = encoding;
        }

        void writeData() {
            // Create a row and put some cells in it. Rows are 0 based.
            Row row = sheet.createRow(0);
            Cell cell = row.createCell((short) 0);
            cell.setCellValue(14654);

            //plain string value
            row.createCell(2).setCellValue("This is a string cell");
            //formula
            row.createCell(5).setCellFormula("SUM(A2:B2)");

            row.createCell(6).setCellFormula("HYPERLINK(\"http://google.ch\",\"Google CH\")");
        }

        void save(final String src) throws IOException {
            String fullPath = getPathWithExtension(src);
            // Invoking HSSFWorkbook.getBytes() does not return all the data
            // necessary to re- construct a complete Excel file
            // We need to use write method with the ByteArrayOutputStream to get at the byte array
            ByteArrayOutputStream byteOut = new ByteArrayOutputStream();
            wb.write(byteOut);
            // get the file in string
            String fileString = new String(byteOut.toByteArray(), Charset.forName(encoding));
            //write the file using stream writer
            try (OutputStreamWriter outputStreamWriter = new OutputStreamWriter(new FileOutputStream(fullPath), encoding)) {
                outputStreamWriter.write(fileString);
            }
            byteOut.close();
        }

        private String getPathWithExtension(String src) {
            return !src.endsWith(".xls") ? src + ".xls" : src;
        }
    }
}