POI使用案例01---读取excel的数据

1、创建maven项目 2、导入poi的依赖

        
            org.apache.poi
            poi
            3.17
        

        
        
            org.apache.poi
            poi-ooxml
            3.17
        

3、读取excel内容 3.1、读取一个单元格

3.2、遍历单元格

//将一个excel文件转为一个Workbook对象。
            Workbook workbook = WorkbookFactory.create(new File("src/main/resources/13523712402_http.xls"));
            //读取一个sheet
            Sheet sheet = workbook.getSheetAt(0);
            Row row = null;
            for (int i = 0; i < 2; i++) {
                row = sheet.getRow(i);
                for (int j = 0; j < 3; j++) {
                    Cell cell = row.getCell(j);
                    //System.out.println(cell.getCellTypeEnum());
                    System.out.println(cell.getStringCellValue());
                }
            }

报错: java.lang.IllegalStateException: Cannot get a STRING value from a NUMERIC cell, 无法将数值类型转化成String 原因： getStringCellValue()无法将数值类型转化为string

解决方法:根据cell的type, 将结果都转为String

    private String getCellValue(Cell cell) {
        String result = null;
        switch (cell.getCellTypeEnum()) {
        case BLANK:
            result = "";
            break;
        case NUMERIC: 
            result = String.valueOf(cell.getNumericCellValue());
            break;
        case FORMULA:
            result = String.valueOf(cell.getCellFormula());
            break;
        case STRING:
            result = cell.getStringCellValue();
            break;
        default:
            break;
        }
        return result;
    }