poi处理本地excel文件

poi依赖

 <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>4.1.2</version>
        </dependency>

public static void main(String[] args) {
        File file = new File("文件路径");
        Workbook workbook = readExcel(file);
        handleData(workbook);
        try {
            FileOutputStream stream = FileUtils.openOutputStream(file);
            workbook.write(stream);
            stream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

示例1

public static void handleData(Workbook workbook){
        Sheet sheet = workbook.getSheetAt(0);
        Row titleRow = sheet.getRow(0);
        short lastCellNum = titleRow.getLastCellNum();
        int titleNum = -1;
        for (int i = 0; i < lastCellNum; i++) {
            if (titleRow.getCell(i).getStringCellValue().equals("征用")) {
                titleNum = i;
                break;
            }
        }

        for (int rowNum = 0; rowNum <= sheet.getLastRowNum(); rowNum++) {
            Row row = sheet.getRow(rowNum);
            if (row != null) {
                if (row.getLastCellNum() < 1 || "".equals(row.getCell(0))) {
                    continue;
                }
            }
                Cell cell = row.getCell(titleNum);
            if (cell == null) {
                row.createCell(titleNum).setCellValue("呀呀呀");
            } else if ("".equals(cell.getStringCellValue())) {
                cell.setCellValue("呀呀呀呀呀");
            }
        }
    }

获取工作簿

 public static Workbook readExcel(File file) {
        Workbook xssfWorkbook = null;
        try {
            //获取文件名字
            String fileName = file.getName();
            //获取文件类型
            String fileType = fileName.substring(fileName.lastIndexOf(".") + 1);
            //获取输入流
            InputStream stream = new FileInputStream(file);
            //获取工作薄
            xssfWorkbook = null;
            if (fileType.equals("xls")) {
                xssfWorkbook = new HSSFWorkbook(stream);
            } else if (fileType.equals("xlsx")) {
                xssfWorkbook = new XSSFWorkbook(stream);
            } else {
                System.out.println("excel格式不正确");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return xssfWorkbook;
    }
```java
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