springboot+easyexcel实现下载excels模板下拉选择

定义下拉注解

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExcelDropDown {/*** 固定下拉选项*/String[] source() default {};/*** 动态数据源key（从上下文中获取）*/String sourceMethod() default "";/*** 下拉框起始行（默认从第2行开始）*/int firstRow() default 1;/*** 下拉框结束行（默认到10000行）*/int lastRow() default 10000;
}

实现CellWriteHandler 接口

@Slf4j
public class DynamicDropDownHandler implements CellWriteHandler {private final ApplicationContext applicationContext;public DynamicDropDownHandler(ApplicationContext applicationContext) {this.applicationContext = applicationContext;}@Overridepublic void beforeCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Row row, Head head, Integer columnIndex, Integer relativeRowIndex, Boolean isHead) {}@Overridepublic void afterCellCreate(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {Class clazz = writeSheetHolder.getClazz();try {String fieldName = head.getFieldName();Field field = clazz.getDeclaredField(fieldName);ExcelDropDown dropDown = field.getAnnotation(ExcelDropDown.class);if (dropDown != null) {String[] source = dropDown.source();if (source.length == 0) {//判断是否有从库中查询数据的方法String method = dropDown.sourceMethod();if (null != method && !"".equals(method)) {source = applicationContext.getBean(method, String[].class);}if (source.length == 0) {return;}}Sheet sheet = writeSheetHolder.getSheet();Workbook workbook = sheet.getWorkbook();// 1. 创建隐藏Sheet存储下拉选项String optionSheetName = fieldName+"_options";Sheet optionsSheet = workbook.getSheet(optionSheetName);if (optionsSheet == null) {optionsSheet = workbook.createSheet(optionSheetName);workbook.setSheetHidden(workbook.getSheetIndex(optionsSheet), true); // 隐藏Sheet}// 2. 写入选项数据到隐藏Sheetint optionCol = 0; // 使用第一列存储选项for (int i = 0; i < source.length; i++) {Row row = optionsSheet.getRow(i);if (row == null) {row = optionsSheet.createRow(i);}row.createCell(optionCol).setCellValue(source[i]);}// 3. 创建名称引用String rangeName = "DROP_DOWN_" + fieldName.toUpperCase();Name namedRange = workbook.getName(rangeName);if (namedRange == null) {namedRange = workbook.createName();namedRange.setNameName(rangeName);}namedRange.setRefersToFormula(String.format(optionSheetName+"!$A$1:$A$%d", source.length));// 4. 设置数据验证（使用公式引用）DataValidationHelper helper = sheet.getDataValidationHelper();DataValidationConstraint constraint =helper.createFormulaListConstraint(rangeName);// 设置下拉范围：从第二行开始到最大行，当前列int columnIndex = cell.getColumnIndex();CellRangeAddressList addressList = new CellRangeAddressList(1, // 从第二行开始2, // Excel最大行号columnIndex,columnIndex);DataValidation validation = helper.createValidation(constraint, addressList);validation.setSuppressDropDownArrow(true);validation.setShowErrorBox(true);sheet.addValidationData(validation);}} catch (Exception e) {log.error(e.getMessage());}}@Overridepublic void afterCellDispose(WriteSheetHolder writeSheetHolder, WriteTableHolder writeTableHolder, List<CellData> cellDataList, Cell cell, Head head, Integer relativeRowIndex, Boolean isHead) {}
}

使用下载模板接口

    public void downloadTemplate(HttpServletResponse response) {try {// 设置响应头response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");response.setCharacterEncoding("utf-8");String fileName = URLEncoder.encode("模板", "UTF-8").replaceAll("\\+", "%20");response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");// 写入ExcelEasyExcel.write(response.getOutputStream(), ImportVo.class).autoCloseStream(true).registerWriteHandler(new DynamicDropDownHandler(applicationContext)).sheet("Sheet").doWrite(Collections.singletonList(Collections.emptyList())); } catch (Exception e) {throw new RuntimeException(e);}}

实体类

public class ImportVo {@ExcelProperty(value = "动态数据下拉")@ExcelDropDown(sourceMethod = "getNameList")private String name;@ExcelProperty(value = "性别")@ExcelDropDown(source = {"男","女"})private String sex;
}