java poi read write xlsx

package myjava;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.sql.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

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.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

/**
 * Sample Java program to read and write Excel file in Java using Apache POI
 * http
 * ://java67.blogspot.tw/2014/09/how-to-read-write-xlsx-file-in-java-apache-poi
 * -example.html
 */
public class XLSXReaderWriter {

	public static void main(String[] args) {

		try {
			File excel = new File("/mnt/data/test.xlsx");

			writeXlsx(excel);
			readXlsx(excel);

		} catch (FileNotFoundException fe) {
			fe.printStackTrace();
		} catch (IOException ie) {
			ie.printStackTrace();
		}
	}

	static void writeXlsx(File excel) throws IOException {

		XSSFWorkbook book = new XSSFWorkbook();
		Sheet sheet = book.createSheet();
		// writing data into XLSX file
		Map<String, Object[]> newData = new HashMap<String, Object[]>();
		newData.put("7", new Object[] { 7d, "Sonya", "75K", "SALES", "Rupert" });
		newData.put("8", new Object[] { 8d, "Kris", "85K", "SALES", "Rupert" });
		newData.put("9", new Object[] { 9d, "Dave", "90K", "SALES", "Rupert" });

		Set<String> newRows = newData.keySet();
		int rownum = sheet.getLastRowNum();

		for (String key : newRows) {
			Row row = sheet.createRow(rownum++);
			Object[] objArr = newData.get(key);
			int cellnum = 0;
			for (Object obj : objArr) {
				Cell cell = row.createCell(cellnum++);
				if (obj instanceof String) {
					cell.setCellValue((String) obj);
				} else if (obj instanceof Boolean) {
					cell.setCellValue((Boolean) obj);
				} else if (obj instanceof Date) {
					cell.setCellValue((Date) obj);
				} else if (obj instanceof Double) {
					cell.setCellValue((Double) obj);
				}
			}
		}

		// open an OutputStream to save written data into Excel file
		FileOutputStream os = new FileOutputStream(excel);
		book.write(os);
		System.out.println("Writing on Excel file Finished ...");

		// Close workbook, OutputStream and Excel file to prevent leak
		os.close();
	}

	static void readXlsx(File excel) throws IOException {

		FileInputStream fis = new FileInputStream(excel);
		XSSFWorkbook book = new XSSFWorkbook(fis);
		XSSFSheet sheet = book.getSheetAt(0);

		Iterator<Row> itr = sheet.iterator();

		// Iterating over Excel file in Java
		while (itr.hasNext()) {
			Row row = itr.next();

			// Iterating over each column of Excel file
			Iterator<Cell> cellIterator = row.cellIterator();
			while (cellIterator.hasNext()) {

				Cell cell = cellIterator.next();

				switch (cell.getCellType()) {
				case Cell.CELL_TYPE_STRING:
					System.out.print(cell.getStringCellValue() + "\t");
					break;
				case Cell.CELL_TYPE_NUMERIC:
					System.out.print(cell.getNumericCellValue() + "\t");
					break;
				case Cell.CELL_TYPE_BOOLEAN:
					System.out.print(cell.getBooleanCellValue() + "\t");
					break;
				default:

				}
			}
			System.out.println("");
		}
		book.close();
		fis.close();

	}
}

Maven dependencies for poi:

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>3.11</version>
</dependency>

    <dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>3.11</version>
</dependency>