Java開発スキルがわかる：Excelファイルの読み書き機能を実装

import org.apache.poi.ss.usermodel.*; import org.apache.poi.xssf.usermodel.XSSFWorkbook; import java.io.FileInputStream; import java.io.IOException; public class ExcelReader { public static void main(String[] args) { try { FileInputStream fis = new FileInputStream("path/to/excel.xlsx"); Workbook workbook = new XSSFWorkbook(fis); Sheet sheet = workbook.getSheetAt(0); for (Row row : sheet) { for (Cell cell : row) { CellType cellType = cell.getCellType(); if (cellType == CellType.STRING) { String value = cell.getStringCellValue(); System.out.print(value + " "); } else if (cellType == CellType.NUMERIC) { double value = cell.getNumericCellValue(); System.out.print(value + " "); } } System.out.println(); } workbook.close(); fis.close(); } catch (IOException e) { e.printStackTrace(); } } }

import org.apache.poi.ss.usermodel.*; import org.apache.poi.xssf.usermodel.XSSFWorkbook; import java.io.FileOutputStream; import java.io.IOException; public class ExcelWriter { public static void main(String[] args) { try { Workbook workbook = new XSSFWorkbook(); Sheet sheet = workbook.createSheet("Sheet1"); Row headerRow = sheet.createRow(0); Cell headerCell1 = headerRow.createCell(0); headerCell1.setCellValue("Name"); Cell headerCell2 = headerRow.createCell(1); headerCell2.setCellValue("Age"); Row dataRow = sheet.createRow(1); Cell dataCell1 = dataRow.createCell(0); dataCell1.setCellValue("John"); Cell dataCell2 = dataRow.createCell(1); dataCell2.setCellValue(25); FileOutputStream fos = new FileOutputStream("path/to/excel.xlsx"); workbook.write(fos); workbook.close(); fos.close(); } catch (IOException e) { e.printStackTrace(); } } }