使用easyExcel实现文件读写

实现流程

1.导入依赖

2.定义数据模型

3.定义监听器

4.读取或写入数据

5.释放资源

实现

导入依赖

<dependency><groupId>com.alibaba</groupId><artifactId>easyexcel</artifactId><version>3.1.3</version>
</dependency>

定义数据模型

@@ExcelProperty(value = "id" ,index = 0)  列的字段名称和索引

@Data
@AllArgsConstructor
@NoArgsConstructor
public class CategoryExcelVo {@ExcelProperty(value = "id" ,index = 0)private Long id;@ExcelProperty(value = "名称" ,index = 1)private String name;@ExcelProperty(value = "图片url" ,index = 2)private String imageUrl ;@ExcelProperty(value = "上级id" ,index = 3)private Long parentId;@ExcelProperty(value = "状态" ,index = 4)private Integer status;@ExcelProperty(value = "排序" ,index = 5)private Integer orderNum;}

定义监听器

public class ExcelListener<T> extends AnalysisEventListener<T> {private static final int BATCH_COUNT = 100;private List cacheList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);private CategoryMapper categoryMapper;public ExcelListener(CategoryMapper categoryMapper){this.categoryMapper = categoryMapper;}//读取结束之前，每次调用invoke()方法@Overridepublic void invoke(T t, AnalysisContext analysisContext) {CategoryExcelVo categoryExcelVo = (CategoryExcelVo) t;cacheList.add(categoryExcelVo);if(cacheList.size() >= BATCH_COUNT){saveData();cacheList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);}}@Overridepublic void doAfterAllAnalysed(AnalysisContext analysisContext) {saveData();}private void saveData(){categoryMapper.insertData(cacheList);}
}

读取

@Override
public void importData(MultipartFile file) {try {ExcelListener<CategoryExcelVo> listener = new ExcelListener<>(categoryMapper);EasyExcel.read(file.getInputStream(),CategoryExcelVo.class,listener).sheet().doRead();} catch (IOException e) {throw new GuiguException(ResultCodeEnum.DATA_ERROR);}
}

写入

@Overridepublic void exportData(HttpServletResponse response) {try {// 设置响应结果类型response.setContentType("application/vnd.ms-excel");response.setCharacterEncoding("utf-8");// 这里URLEncoder.encode可以防止中文乱码 当然和easyexcel没有关系String fileName = URLEncoder.encode("分类数据", "UTF-8");response.setHeader("Content-disposition", "attachment;filename=" + fileName + ".xlsx");//response.setHeader("Access-Control-Expose-Headers", "Content-Disposition");// 查询数据库中的数据List<Category> categories = categoryMapper.selectAll();List<CategoryExcelVo> res = new ArrayList<>();categories.forEach(category ->{CategoryExcelVo temp = new CategoryExcelVo();BeanUtils.copyProperties(category,temp,CategoryExcelVo.class);res.add(temp);});EasyExcel.write(response.getOutputStream(),CategoryExcelVo.class).sheet().doWrite(res);} catch (IOException e) {throw new GuiguException(ResultCodeEnum.DATA_ERROR);}}

使用POI实现Excel文件的读写

导入依赖

<dependency><groupId>org.apache.poi</groupId><artifactId>poi</artifactId><version>5.2.0</version>
</dependency>
<dependency><groupId>org.apache.poi</groupId><artifactId>poi-ooxml</artifactId><version>5.2.0</version>
</dependency>

读取

 /*** 通过POI获取Excel文件中的内容* @throws Exception*/public static void read() throws Exception{FileInputStream in = new FileInputStream("E:\\info.xlsx");XSSFWorkbook excel = new XSSFWorkbook(in);XSSFSheet sheet = excel.getSheetAt(0);//获取有文字的最后一行行号int lastRowNum = sheet.getLastRowNum();for(int i = 1;i <= lastRowNum;i++){//获得某一行XSSFRow row = sheet.getRow(i);System.out.println(row.getCell(1).getStringCellValue() + " " +row.getCell(2).getStringCellValue());}excel.close();in.close();}

写入

    /*** 通过POI创建Excel文件且写入文件内容*/public static void write() throws Exception{//在内容中创建一个Excel文件XSSFWorkbook excel = new XSSFWorkbook();//在Excel文件中创建sheet页XSSFSheet sheet = excel.createSheet("info");//在Excel文件中创建对象  索引从0开始XSSFRow row = sheet.createRow(1);//创建单元格并且写入文件内容row.createCell(1).setCellValue("姓名");row.createCell(2).setCellValue("城市");//创建一个新行row = sheet.createRow(2);//创建单元格并且写入文件内容row.createCell(1).setCellValue("张三");row.createCell(2).setCellValue("北京");row = sheet.createRow(3);//创建单元格并且写入文件内容row.createCell(1).setCellValue("李四");row.createCell(2).setCellValue("南京");//通过输出流将内存中的内容写入磁盘OutputStream out = new FileOutputStream(new File("E:\\info.xlsx"));excel.write(out);out.close();excel.close();}

使用场景（数据导出）

 public void exportBusinessData(HttpServletResponse response) {//查数据库，获取营业数据LocalDate dateBegin = LocalDate.now().minusDays(30);LocalDate dateEnd = LocalDate.now().minusDays(1);LocalDateTime begin = LocalDateTime.of(dateBegin, LocalTime.MIN);LocalDateTime end = LocalDateTime.of(dateEnd, LocalTime.MAX);//查询概览数据BusinessDataVO businessDataVO = workspaceService.getBusinessData(begin, end);//通过POI将数据写入到Excel中InputStream in = this.getClass().getClassLoader().getResourceAsStream("template/运营数据报表模板.xlsx");try {//基于模板文件创建一个新的Excel文件XSSFWorkbook excel = new XSSFWorkbook(in);//填充数据//获取表格文件sheet标签页XSSFSheet sheet = excel.getSheet("sheet1");//填充时间段sheet.getRow(1).getCell(1).setCellValue("时间: " + dateBegin + " 至 " + dateEnd);//获得第四行XSSFRow row = sheet.getRow(3);row.getCell(2).setCellValue(businessDataVO.getTurnover());row.getCell(4).setCellValue(businessDataVO.getOrderCompletionRate());row.getCell(6).setCellValue(businessDataVO.getNewUsers());row = sheet.getRow(4);row.getCell(2).setCellValue(businessDataVO.getValidOrderCount());row.getCell(4).setCellValue(businessDataVO.getUnitPrice());for(int i = 0;i < 30;i++){LocalDate date = dateBegin.plusDays(i);//查询某一天的数据BusinessDataVO businessData = workspaceService.getBusinessData(LocalDateTime.of(date, LocalTime.MIN), LocalDateTime.of(date, LocalTime.MAX));row = sheet.getRow(7 + i);row.getCell(1).setCellValue(date.toString());row.getCell(2).setCellValue(businessData.getTurnover());row.getCell(3).setCellValue(businessData.getValidOrderCount());row.getCell(4).setCellValue(businessData.getOrderCompletionRate());row.getCell(5).setCellValue(businessData.getUnitPrice());row.getCell(6).setCellValue(businessData.getNewUsers());}//通过输出流将Excel文件下载到客户端浏览器ServletOutputStream out = response.getOutputStream();excel.write(out);in.close();out.close();excel.close();} catch (IOException e) {e.printStackTrace();}}