SpringBoot集成文件 - 集成POI之Excel导入导出

Apache POI 是用Java编写的免费开源的跨平台的 Java API,Apache POI提供API给Java程序对Microsoft Office格式档案读和写的功能。本文主要介绍通过SpringBoot集成POI工具实现Excel的导入和导出功能。@pdai

知识准备

需要了解POI工具,以及POI对Excel中的对象的封装对应关系。

什么是POI

Apache POI 是用Java编写的免费开源的跨平台的 Java API,Apache POI提供API给Java程序对Microsoft Office格式档案读和写的功能。POI为“Poor Obfuscation Implementation”的首字母缩写,意为“简洁版的模糊实现”。

Apache POI 是创建和维护操作各种符合Office Open XML(OOXML)标准和微软的OLE 2复合文档格式(OLE2)的Java API。用它可以使用Java读取和创建,修改MS Excel文件.而且,还可以使用Java读取和创建MS Word和MSPowerPoint文件。更多请参考官方文档 (opens new window)

POI中基础概念

生成xls和xlsx有什么区别?POI对Excel中的对象的封装对应关系?

生成xls和xlsx有什么区别呢?

XLS XLSX
只能打开xls格式,无法直接打开xlsx格式 可以直接打开xls、xlsx格式
只有65536行、256列 可以有1048576行、16384列
占用空间大 占用空间小,运算速度也会快一点

POI对Excel中的对象的封装对应关系如下:

Excel POI XLS POI XLSX(Excel 2007+)
Excel 文件 HSSFWorkbook (xls) XSSFWorkbook(xlsx)
Excel 工作表 HSSFSheet XSSFSheet
Excel 行 HSSFRow XSSFRow
Excel 单元格 HSSFCell XSSFCell
Excel 单元格样式 HSSFCellStyle HSSFCellStyle
Excel 颜色 HSSFColor XSSFColor
Excel 字体 HSSFFont XSSFFont

实现案例

这里展示SpringBoot集成POI导出用户列表的和导入用户列表的例子。

Pom依赖

引入poi的依赖包

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>5.2.2</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>5.2.2</version>
</dependency>
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导出Excel

UserController中导出的方法

@ApiOperation("Download Excel")
@GetMapping("/excel/download")
public void download(HttpServletResponse response) {
    try {
        SXSSFWorkbook workbook = userService.generateExcelWorkbook();
        response.reset();
        response.setContentType("application/vnd.ms-excel");
        response.setHeader("Content-disposition",
                "attachment;filename=user_excel_" + System.currentTimeMillis() + ".xlsx");
        OutputStream os = response.getOutputStream();
        workbook.write(os);
        workbook.dispose();
    } catch (Exception e) {
        e.printStackTrace();
    }
}
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UserServiceImple中导出Excel的主方法

private static final int POSITION_ROW = 1;
private static final int POSITION_COL = 1;

/**
  * @return SXSSFWorkbook
  */
@Override
public SXSSFWorkbook generateExcelWorkbook() {
    SXSSFWorkbook workbook = new SXSSFWorkbook();
    Sheet sheet = workbook.createSheet();

    int rows = POSITION_ROW;
    int cols = POSITION_COL;

    // 表头
    Row head = sheet.createRow(rows++);
    String[] columns = new String[]{"ID", "Name", "Email", "Phone", "Description"};
    int[] colWidths = new int[]{2000, 3000, 5000, 5000, 8000};
    CellStyle headStyle = getHeadCellStyle(workbook);
    for (int i = 0; i < columns.length; ++i) {
        sheet.setColumnWidth(cols, colWidths[i]);
        addCellWithStyle(head, cols++, headStyle).setCellValue(columns[i]);
    }

    // 表内容
    CellStyle bodyStyle = getBodyCellStyle(workbook);
    for (User user : getUserList()) {
        cols = POSITION_COL;
        Row row = sheet.createRow(rows++);
        addCellWithStyle(row, cols++, bodyStyle).setCellValue(user.getId());
        addCellWithStyle(row, cols++, bodyStyle).setCellValue(user.getUserName());
        addCellWithStyle(row, cols++, bodyStyle).setCellValue(user.getEmail());
        addCellWithStyle(row, cols++, bodyStyle).setCellValue(String.valueOf(user.getPhoneNumber()));
        addCellWithStyle(row, cols++, bodyStyle).setCellValue(user.getDescription());
    }
    return workbook;
}

private Cell addCellWithStyle(Row row, int colPosition, CellStyle cellStyle) {
    Cell cell = row.createCell(colPosition);
    cell.setCellStyle(cellStyle);
    return cell;
}

private List<User> getUserList() {
    return Collections.singletonList(User.builder()
            .id(1L).userName("pdai").email("pdai@pdai.tech").phoneNumber(121231231231L)
            .description("hello world")
            .build());
}

private CellStyle getHeadCellStyle(Workbook workbook) {
    CellStyle style = getBaseCellStyle(workbook);

    // fill
    style.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.getIndex());
    style.setFillPattern(FillPatternType.SOLID_FOREGROUND);

    return style;
}

private CellStyle getBodyCellStyle(Workbook workbook) {
    return getBaseCellStyle(workbook);
}

private CellStyle getBaseCellStyle(Workbook workbook) {
    CellStyle style = workbook.createCellStyle();

    // font
    Font font = workbook.createFont();
    font.setBold(true);
    style.setFont(font);

    // align
    style.setAlignment(HorizontalAlignment.CENTER);
    style.setVerticalAlignment(VerticalAlignment.TOP);

    // border
    style.setBorderBottom(BorderStyle.THIN);
    style.setBottomBorderColor(IndexedColors.BLACK.getIndex());
    style.setBorderLeft(BorderStyle.THIN);
    style.setLeftBorderColor(IndexedColors.BLACK.getIndex());
    style.setBorderRight(BorderStyle.THIN);
    style.setRightBorderColor(IndexedColors.BLACK.getIndex());
    style.setBorderTop(BorderStyle.THIN);
    style.setTopBorderColor(IndexedColors.BLACK.getIndex());

    return style;
}

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导出后的excel如下

导入Excel

我们将上面导出的excel文件导入。

UserController中导入的方法

@ApiOperation("Upload Excel")
@PostMapping("/excel/upload")
public ResponseResult<String> upload(@RequestParam(value = "file", required = true) MultipartFile file) {
    try {
        userService.upload(file.getInputStream());
    } catch (Exception e) {
        e.printStackTrace();
        return ResponseResult.fail(e.getMessage());
    }
    return ResponseResult.success();
}
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UserServiceImple中导入Excel的主方法

@Override
public void upload(InputStream inputStream) throws IOException {
    XSSFWorkbook book = new XSSFWorkbook(inputStream);
    XSSFSheet sheet = book.getSheetAt(0);
    // add some validation here

    // parse data
    int cols;
    for (int i = POSITION_ROW; i < sheet.getLastRowNum(); i++) {
        XSSFRow row = sheet.getRow(i + 1); // 表头不算
        cols = POSITION_COL;
        User user = User.builder()
                .id(getCellLongValue(row.getCell(cols++)))
                .userName(getCellStringValue(row.getCell(cols++)))
                .email(getCellStringValue(row.getCell(cols++)))
                .phoneNumber(Long.parseLong(getCellStringValue(row.getCell(cols++))))
                .description(getCellStringValue(row.getCell(cols++)))
                .build();
        log.info(user.toString());
    }

    book.close();
}

private String getCellStringValue(XSSFCell cell) {
    try {
        if (null!=cell) {
            return String.valueOf(cell.getStringCellValue());
        }
    } catch (Exception e) {
        return String.valueOf(getCellIntValue(cell));
    }
    return "";
}

private long getCellLongValue(XSSFCell cell) {
    try {
        if (null!=cell) {
            return Long.parseLong("" + (long) cell.getNumericCellValue());
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return 0L;
}

private int getCellIntValue(XSSFCell cell) {
    try {
        if (null!=cell) {
            return Integer.parseInt("" + (int) cell.getNumericCellValue());
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return 0;
}
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通过PostMan进行接口测试

执行接口后,后台的日志如下

2022-06-10 21:36:01.720  INFO 15100 --- [nio-8080-exec-2] t.p.s.f.e.p.s.impl.UserServiceImpl       : User(id=1, userName=pdai, email=pdai@pdai.tech, phoneNumber=121231231231, description=hello world)
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示例源码

https://github.com/realpdai/tech-pdai-spring-demos

参考文章

https://poi.apache.org/index.html

联系我

添加@pdai微信

PS:添加时请备注Java全栈,谢谢!