POI

POI既可以将数据写入Excel文件也可以读取Excel文件中的数据接下来分别进行实现。

Apache

dependencygroupIdorg.apache.poi/groupIdartifactIdpoi/artifactIdversion3.16/version

/dependency

dependencygroupIdorg.apache.poi/groupIdartifactIdpoi-ooxml/artifactIdversion3.16/version

/dependency2.2.1

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;

import

java.io.FileOutputStream;public

class

Exception{//在内存中创建一个Excel文件对象XSSFWorkbook

excel

XSSFWorkbook();//创建Sheet页XSSFSheet

sheet

excel.createSheet(itcast);//在Sheet页中创建行0表示第1行XSSFRow

row1

sheet.createRow(0);//创建单元格并在单元格中设置值单元格编号也是从0开始1表示第2个单元格row1.createCell(1).setCellValue(姓名);row1.createCell(2).setCellValue(城市);XSSFRow

row2

sheet.createRow(1);row2.createCell(1).setCellValue(张三);row2.createCell(2).setCellValue(北京);XSSFRow

row3

sheet.createRow(2);row3.createCell(1).setCellValue(李四);row3.createCell(2).setCellValue(上海);FileOutputStream

out

File(D:\\itcast.xlsx));//通过输出流将内存中的Excel文件写入到磁盘上excel.write(out);//关闭资源out.flush();out.close();excel.close();}public

static

在D盘中生成itcast.xlsx文件创建名称为itcast的Sheet页同时将内容成功写入。

2.2.2

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;

import

java.io.FileOutputStream;public

class

File(D:\\itcast.xlsx));//通过输入流读取指定的Excel文件XSSFWorkbook

excel

XSSFWorkbook(in);//获取Excel文件的第1个Sheet页XSSFSheet

sheet

excel.getSheetAt(0);//获取Sheet页中的最后一行的行号int

lastRowNum

sheet.getRow(i);//获取行的第2个单元格XSSFCell

cell1

titleRow.getCell(1);//获取单元格中的文本内容String

cellValue1

cell1.getStringCellValue();//获取行的第3个单元格XSSFCell

cell2

titleRow.getCell(2);//获取单元格中的文本内容String

cellValue2

cell2.getStringCellValue();System.out.println(cellValue1

cellValue2);}//关闭资源in.close();excel.close();}public

static

response*/GetMapping(/export)ApiOperation(导出运营数据报表)public

void

response){reportService.exportBusinessData(response);}3.2service层

Overridepublic

LocalDate.now().minusDays(30);LocalDate

end

LocalDate.now().minusDays(1);//查询概览运营数据提供给Excel模板文件BusinessDataVO

businessData

workspaceService.getBusinessData(LocalDateTime.of(begin,LocalTime.MIN),

LocalTime.MAX));/**class.getResourceAsStream如果path不带/,那么就是从当前class文件的路径下找文件如果path带/,那么就是从类路径.classpath中去找文件*/InputStream

inputStream

this.getClass().getClassLoader().getResourceAsStream(template/运营数据报表模板.xlsx);try

{//基于提供好的模板文件创建一个新的Excel表格对象XSSFWorkbook

excel

XSSFWorkbook(inputStream);//获得Excel文件中的一个Sheet页XSSFSheet

sheet

excel.getSheet(Sheet1);sheet.getRow(1).getCell(1).setCellValue(begin

end);//获得第4行XSSFRow

sheet.getRow(3);//获取单元格row.getCell(2).setCellValue(businessData.getTurnover());row.getCell(4).setCellValue(businessData.getOrderCompletionRate());row.getCell(6).setCellValue(businessData.getNewUsers());row

sheet.getRow(4);row.getCell(2).setCellValue(businessData.getValidOrderCount());row.getCell(4).setCellValue(businessData.getUnitPrice());for

(int

begin.plusDays(i);//准备明细数据businessData

workspaceService.getBusinessData(LocalDateTime.of(date,LocalTime.MIN),

LocalTime.MAX));row

i);row.getCell(1).setCellValue(date.toString());if

(Objects.isNull(businessData.getTurnover())){row.getCell(2).setCellValue(0.0);}else

{row.getCell(2).setCellValue(businessData.getTurnover());}if

(Objects.isNull(businessData.getValidOrderCount())){row.getCell(3).setCellValue(0);}else

{row.getCell(3).setCellValue(businessData.getValidOrderCount());}if

(Objects.isNull(businessData.getOrderCompletionRate())){row.getCell(4).setCellValue(0.0);}else

{row.getCell(4).setCellValue(businessData.getOrderCompletionRate());}if

(Objects.isNull(businessData.getUnitPrice())){row.getCell(5).setCellValue(0.0);}else

{row.getCell(5).setCellValue(businessData.getUnitPrice());}if

(Objects.isNull(businessData.getNewUsers())){row.getCell(6).setCellValue(0);}else

{row.getCell(6).setCellValue(businessData.getNewUsers());}}//通过输出流将文件下载到客户端浏览器中ServletOutputStream

out

response.getOutputStream();excel.write(out);//关闭资源out.flush();out.close();excel.close();}catch

(IOException