java如何导入excel文件

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.ss.usermodel.DataFormatter;
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;

HSSFWorkbook workbook = null;
try {
    // 读取Excel文件
    InputStream inputStream = new FileInputStream('c:\test.xlsx');
    workbook = new HSSFWorkbook(inputStream);
    inputStream.close();
} catch (Exception e) {
    e.printStackTrace();
}

// 遍历Excel Sheetfor (int numSheet = 0; numSheet < workbook.getNumberOfSheets(); numSheet++) {
    workbook.getSheetAt(numSheet);
}

HSSFSheet sheet = workbook.getSheetAt(0);
if (sheet != null) {
    // 循环行
    for     (int rowNum = 1; rowNum <= sheet.getLastRowNum(); rowNum++) {
        HSSFRow row = sheet.getRow(rowNum);
        if (row == null) {
            continue;// 忽略并继续读取
        }
        HSSFCell cell = row.getCell(0);
      if (cell == null) {
            continue;
        }
      //System.out.println(&#39;cell.getStringCellValue0():&#39; + cell.getStringCellValue());
        cell = row.getCell(1);
       if (cell == null) {
            continue;
       }
        //System.out.println(&#39;cell.getStringCellValue1():&#39; + cell.getStringCellValue());
   }
}

DataFormatter formatter = new DataFormatter();
String val = formatter.formatCellValue(sheet.getRow(col).getCell(row));