基于注解和EasyExcel指定单元格下拉选内容
基于注解和EasyExcel指定单元格下拉选内容
１.场景描述
要求基于EasyExcel进行导出，有的单元格的内容必须是通过下拉选内容进行编辑，以便于后续修改导入，规避用户随意录入数据。
2.编写测试
这里只省略部分代码，避免喧宾夺主。
大概思路就是根据业务要求查询出数据，并利用EasyExcel进行导出。
@PostMapping("/export")
@ApiOperation("明细统计导出")
public void exportRiskDetailReport(@Valid DetailReportDto detailReportDto) throws ParseException, IOException {
EasyExcelUtil.excelDropdownExport(1, DetailReportViewDto.class, "风险排查明细统计数据" + DateUtil.format(new Date(), "yyyyMMddHHmmssS"), list, null);
}
}
3.代码实现
导出工具类
在导出时我们需要将自定义的处理器注册到EasyExcel中。
@Slf4j
public class EasyExcelUtil {
public static void excelDropdownExport(int firstRow,Class head, String excelname, List data, String sheetName) {
ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
HttpServletResponse response = requestAttributes.getResponse();
response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
response.setCharacterEncoding("utf-8");
try {
// 这里URLEncoder.encode可以防止浏览器端导出excel文件名中文乱码 当然和easyexcel没有关系
String fileName = URLEncoder.encode(excelname, "UTF-8").replaceAll("\\+", "%20");
response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");
EasyExcel.write(response.getOutputStream(), head)
//导出时将单元格数据转换为Number类型，导入时将数据转换为Long类型
.registerConverter(new LongStringConverter())
//自定义下拉选内容处理器
.registerWriteHandler(new CellDropdownHandler(firstRow,data))
.sheet(sheetName == null ? "Sheet1" : sheetName).doWrite(data);
} catch (Exception e) {
e.printStackTrace();
log.error("导出数据失败: " + e.getMessage());
}
}
}
定义下拉选注解
这里我采用的是固定内容下拉，将需要下拉的内容通过注解进行传递，当然如果需要从数据库中获取下拉内容也可以直接指定Class对象，在后续处理中从Spring上下文中获取对象,比如通过下面这样的代码
@Component
public final class SpringUtils implements BeanFactoryPostProcessor, ApplicationContextAware
{
public static <T> T getBean(Class<T> clz) throws BeansException
{
T result = (T) beanFactory.getBean(clz);
return result;
}
}
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.FIELD})
public @interface SelectData {
/**
* 定义固定下拉内容
* @return
*/
String[] values() default {};
}
核心代码
单元格下拉内容处理
import com.alibaba.excel.annotation.ExcelProperty;
import com.alibaba.excel.metadata.CellData;
import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.write.handler.CellWriteHandler;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.metadata.holder.WriteTableHolder;
import org.apache.commons.collections.CollectionUtils;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddressList;
import java.lang.reflect.Field;
import java.util.List;
/**
* 单元格下拉
*/
public class CellDropdownHandler implements CellWriteHandler {
private int firstRow;
private int lastRow;
private List<Object> list;
private CellDropdownHandler() {
}
//通过构造的方式传入 firstRow 内容的起始行 list要导出的数据集合
public CellDropdownHandler(int firstRow,List<Object> list) {
this.list = list;
this.firstRow = firstRow;
lastRow = list.size();
}
@Override
public void beforeCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Row row, Head head, Integer columnIndex, Integer relativeRowIndex, Boolean isHead) {
if(CollectionUtils.isNotEmpty(list)){
Sheet sheet = writeSheetHolder.getSheet();
DataValidationHelper helper = sheet.getDataValidationHelper();
String fieldName = head.getFieldName();
Class clazz = writeSheetHolder.getClazz();
Field[] fields = clazz.getDeclaredFields();
for (Field field : fields) {
if(fieldName.equals(field.getName()) && field.isAnnotationPresent(SelectData.class) && field.isAnnotationPresent(ExcelProperty.class)){
SelectData selectData = field.getAnnotation(SelectData.class);
// 设置下拉单元格的首行 末行 首列 末列 【因为我的业务是第一行是列头，第二行是内容 所以入参下标从1开始，行数通过外层list集合获取】
CellRangeAddressList rangeList = new CellRangeAddressList(firstRow, lastRow, columnIndex, columnIndex);
// 下拉列表约束数据
DataValidationConstraint constraint = helper.createExplicitListConstraint(selectData.values());
// 设置约束
DataValidation validation = helper.createValidation(constraint, rangeList);
// 阻止输入非下拉选项的值
validation.setErrorStyle(DataValidation.ErrorStyle.STOP);
validation.setShowErrorBox(true);
validation.setSuppressDropDownArrow(true);
validation.createErrorBox("提示", "此值与单元格定义格式不一致");
sheet.addValidationData(validation);
}
}
}
}
@Override
public void afterCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {
}
@Override
public void afterCellDataConverted(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, CellData cellData, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {
}
@Override
public void afterCellDispose(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, List<CellData> cellDataList, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {
}
}
- 参数说明
firstRow是只excel内容从哪一行开始，下表从0开始，除去表头。
lastRow是excel的最后一行
list要导出的数据集合
4.测试效果
当下拉单元格填入和下拉不一致的内容时，给出提示并阻止继续编辑单元格。
下拉内容如下