poi实现excel导入

Apache POI是一个用Java编写的开放源代码的库，它可以帮助我们处理Microsoft Office格式的文档，如Excel、Word、PowerPoint等。下面是使用Apache POI实现Excel导入的步骤：

1. 引入POI的jar包，可以在官网进行下载：https://poi.apache.org/download.html

2. 创建工作簿对象Workbook，根据Excel文件的版本选择HSSFWorkbook或XSSFWorkbook

   InputStream inputStream = new FileInputStream(new File("file.xlsx"));
   Workbook workbook = new XSSFWorkbook(inputStream);

3. 获取工作表对象Sheet，根据表名或索引获取

   Sheet sheet = workbook.getSheet("Sheet1");

4. 遍历行Row和列Cell，读取数据

   for (Row row : sheet) {
       for (Cell cell : row) {
           //获取单元格的值
           String cellValue = cell.getStringCellValue();
       }
   }

5. 关闭工作簿和输入流

   workbook.close();
   inputStream.close();

完整的代码示例：

public static void main(String[] args) throws IOException {
    InputStream inputStream = new FileInputStream(new File("file.xlsx"));
    Workbook workbook = new XSSFWorkbook(inputStream);
    Sheet sheet = workbook.getSheet("Sheet1");
    for (Row row : sheet) {
        for (Cell cell : row) {
            String cellValue = cell.getStringCellValue();
            System.out.print(cellValue + "\t");
        }
        System.out.println();
    }
    workbook.close();
    inputStream.close();
}