编写程序实现JAVA创建EXCEL文件、向EXCEL中输入数据、从EXCEL中读取数据等操作

1. 创建Excel文件：

public class CreateExcel {
    public static void main(String[] args) throws IOException {
        //创建工作簿
        Workbook workbook = new XSSFWorkbook();
        //创建sheet
        Sheet sheet = workbook.createSheet("sheet1");
        //创建行
        Row row = sheet.createRow(0);
        //创建单元格
        Cell cell = row.createCell(0);
        //设置单元格的值
        cell.setCellValue("Hello World!");
        //输出Excel文件
        FileOutputStream outputStream = new FileOutputStream("test.xlsx");
        workbook.write(outputStream);
        outputStream.close();
        System.out.println("Excel文件创建成功！");
    }
}

2. 向Excel中写入数据：

public class WriteExcel {
    public static void main(String[] args) throws IOException {
        //读取已有的Excel文件
        FileInputStream inputStream = new FileInputStream("test.xlsx");
        Workbook workbook = new XSSFWorkbook(inputStream);
        //获取sheet
        Sheet sheet = workbook.getSheet("sheet1");
        //创建行
        Row row = sheet.createRow(1);
        //创建单元格
        Cell cell = row.createCell(0);
        //设置单元格的值
        cell.setCellValue("Java");
        //输出Excel文件
        FileOutputStream outputStream = new FileOutputStream("test.xlsx");
        workbook.write(outputStream);
        outputStream.close();
        System.out.println("Excel文件写入成功！");
    }
}

3. 从Excel中读取数据：

public class ReadExcel {
    public static void main(String[] args) throws IOException {
        //读取已有的Excel文件
        FileInputStream inputStream = new FileInputStream("test.xlsx");
        Workbook workbook = new XSSFWorkbook(inputStream);
        //获取sheet
        Sheet sheet = workbook.getSheet("sheet1");
        //获取行数和列数
        int rowNum = sheet.getLastRowNum();
        int colNum = sheet.getRow(0).getLastCellNum();
        //读取数据
        for (int i = 0; i <= rowNum; i++) {
            Row row = sheet.getRow(i);
            for (int j = 0; j < colNum; j++) {
                Cell cell = row.getCell(j);
                System.out.print(cell.toString() + "\t");
            }
            System.out.println();
        }
        inputStream.close();
        System.out.println("Excel文件读取成功！");
    }
}