用JAVA写一个excel导入

非常感谢您的提问，我可以为您提供以下JAVA代码来实现excel导入功能：

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Iterator;
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.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class ExcelImporter {
    public static void main(String[] args) {
        try {
            FileInputStream file = new FileInputStream(new File("example.xlsx"));

            // Create Workbook instance holding reference to .xlsx file
            Workbook workbook = new XSSFWorkbook(file);

            // Get first/desired sheet from the workbook
            Sheet sheet = workbook.getSheetAt(0);

            // Iterate through each rows one by one
            Iterator<Row> rowIterator = sheet.iterator();
            while (rowIterator.hasNext()) {
                Row row = rowIterator.next();
                // For each row, iterate through all the columns
                Iterator<Cell> cellIterator = row.cellIterator();

                while (cellIterator.hasNext()) {
                    Cell cell = cellIterator.next();
                    // Check the cell type and format accordingly
                    switch (cell.getCellType()) {
                        case Cell.CELL_TYPE_NUMERIC:
                            System.out.print(cell.getNumericCellValue() + "\t");
                            break;
                        case Cell.CELL_TYPE_STRING:
                            System.out.print(cell.getStringCellValue() + "\t");
                            break;
                    }
                }
                System.out.println("");
            }
            file.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

请注意，这只是一个简单的示例代码，您需要根据您的具体需求进行修改和优化。