读写excel(.xls or .xlsx)

     <!--poi-->
        <!-- https://mvnrepository.com/artifact/org.apache.poi/poi -->
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>3.17</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.poi/poi-ooxml -->
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>3.17</version>
        </dependency>

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Iterator;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

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

public class ReadWriteExcelFile {

    public static void readXLSFile() throws IOException
    {
        InputStream ExcelFileToRead = new FileInputStream("E:/excel/Test.xls");
        XSSFWorkbook wb = new XSSFWorkbook(ExcelFileToRead);
//        HSSFWorkbook wb = new HSSFWorkbook(ExcelFileToRead);

//        HSSFSheet sheet=wb.getSheetAt(0);
//        HSSFRow row;
//        HSSFCell cell;
        XSSFSheet sheet = wb.getSheetAt(0);
        XSSFRow row;
        XSSFCell cell;

        Iterator rows = sheet.rowIterator();

        while (rows.hasNext())
        {
            row=(XSSFRow) rows.next();
            Iterator cells = row.cellIterator();

            while (cells.hasNext())
            {
                cell=(XSSFCell) cells.next();

                if (cell.getCellType() == XSSFCell.CELL_TYPE_STRING)
                {
                    System.out.print(cell.getStringCellValue()+" ");
                }
                else if(cell.getCellType() == XSSFCell.CELL_TYPE_NUMERIC)
                {
                    System.out.print(cell.getNumericCellValue()+" ");
                }
                else
                {
                    //U Can Handel Boolean, Formula, Errors
                }
            }
            System.out.println();
        }

    }

    public static void writeXLSFile() throws IOException {

        String excelFileName = "E:/excel/Test001.xls";//name of excel file

        String sheetName = "name";//name of sheet
//        String sheetId = "id";
//        String sheetAge = "age";

        HSSFWorkbook wb = new HSSFWorkbook();
        HSSFSheet sheet = wb.createSheet(sheetName) ;

        //iterating r number of rows
        for (int r=0;r < 5; r++ )
        {
            HSSFRow row = sheet.createRow(r);

            //iterating c number of columns
            for (int c=0;c < 5; c++ )
            {
                HSSFCell cell = row.createCell(c);

                cell.setCellValue("Cell "+r+" "+c);
            }
        }

        FileOutputStream fileOut = new FileOutputStream(excelFileName);

        //write this workbook to an Outputstream.
        wb.write(fileOut);
        fileOut.flush();
        fileOut.close();
    }

    public static void readXLSXFile() throws IOException
    {
        InputStream ExcelFileToRead = new FileInputStream("E:/excel/Test.xlsx");
        XSSFWorkbook  wb = new XSSFWorkbook(ExcelFileToRead);

        XSSFWorkbook test = new XSSFWorkbook();

        XSSFSheet sheet = wb.getSheetAt(0);
        XSSFRow row;
        XSSFCell cell;

        Iterator rows = sheet.rowIterator();

        while (rows.hasNext())
        {
            row=(XSSFRow) rows.next();
            Iterator cells = row.cellIterator();
            while (cells.hasNext())
            {
                cell=(XSSFCell) cells.next();

                if (cell.getCellType() == XSSFCell.CELL_TYPE_STRING)
                {
                    System.out.print(cell.getStringCellValue()+" ");
                }
                else if(cell.getCellType() == XSSFCell.CELL_TYPE_NUMERIC)
                {
                    System.out.print(cell.getNumericCellValue()+" ");
                }
                else
                {
                    //U Can Handel Boolean, Formula, Errors
                }
            }
            System.out.println();
        }

    }

    public static void writeXLSXFile() throws IOException {

        String excelFileName = "E:/excel/Test001.xlss";//name of excel file

        String sheetName = "name";//name of sheet

        XSSFWorkbook wb = new XSSFWorkbook();
        XSSFSheet sheet = wb.createSheet(sheetName) ;

        //iterating r number of rows
        for (int r=0;r < 5; r++ )
        {
            XSSFRow row = sheet.createRow(r);

            //iterating c number of columns
            for (int c=0;c < 5; c++ )
            {
                XSSFCell cell = row.createCell(c);

                cell.setCellValue("Cell "+r+" "+c);
            }
        }

        FileOutputStream fileOut = new FileOutputStream(excelFileName);

        //write this workbook to an Outputstream.
        wb.write(fileOut);
        fileOut.flush();
        fileOut.close();
    }

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

        writeXLSFile();
        readXLSFile();

        writeXLSXFile();
        readXLSXFile();

    }

}