Java反射获取实例并填充注解值

1.场景

下载导入模版

2.普通实现方式

实现很简单，看着不那么优雅

  @GetMapping("/export-detail-template")@Operation(summary = "导出订单需求单明细导入模版 Excel")@OperateLog(type = EXPORT)public void exportTemplate(HttpServletResponse response) throws IOException {final DemandDetailImportTemplateVO templateVO = new DemandDetailImportTemplateVO();templateVO.setSeq(1);templateVO.setCustomerName("黄金大爷");templateVO.setSaleMan("张三");templateVO.setSkuNo("ES01BC0010");templateVO.setProductName("福叠（蝴蝶）");templateVO.setCategoryName("耳饰");templateVO.setBaseWeight("50");templateVO.setWeightSpan("40-50");templateVO.setNum(3);templateVO.setQualityRequired("足金999");templateVO.setPrintContent("无");templateVO.setCreateTime("2023/1/7  15:12:13");templateVO.setTimeRequired("2023/2/7  15:12:13");templateVO.setGuessWeight("49.99");templateVO.setRemark("无备注");ExcelUtils.write(response, "订单需求单明细导入模版.xls", "数据",DemandDetailImportTemplateVO.class,Collections.singletonList(templateVO));}

3. 利用反射+注解设置值方式

3.1 业务代码

@GetMapping("/export-detail-template")@Operation(summary = "导出订单需求单明细导入模版 Excel")@OperateLog(type = EXPORT)public void exportTemplate(HttpServletResponse response) {try {ExcelUtils.write(response, "订单需求单明细导入模版.xls", "数据", DemandDetailImportTemplateVO.class,Collections.singletonList(ReflUtil.getInstanceFillAnnotationValue(DemandDetailImportTemplateVO.class)));} catch (Exception e) {log.error("下载导入模版异常::" + e.getMessage());throw new ServiceException("下载导入模版异常");}}

3.2 业务实体

@Data
@Builder
@Accessors(chain = false)
public class DemandOrderImportVO {@ExcelIgnoreprivate Integer req;@ExcelProperty("客户名称")@Schema(description = "客户名称", example = "黄金大爷")private String customerName;@ExcelProperty("业务")@Schema(description = "业务", example = "张三")private String saleMan;@ExcelProperty("款式编码")@Schema(description = "款式编码", example = "ES01BC0010")private String skuNo;@ExcelProperty("产品图片")@Schema(description = "产品图片")private URL imageUrl;@ExcelProperty("产品名称")@Schema(description = "产品名称", example = "福叠（蝴蝶）")private String productName;@ExcelProperty("品类")@Schema(description = "品类", example = "耳饰")private String categoryName;@ExcelProperty("样板克重")@Schema(description = "样板克重", example = "50")private String baseWeight;@ExcelProperty("克重范围")@Schema(description = "克重范围", example = "40-50")private String weightSpan;@ExcelProperty("件数")@Schema(description = "件数", example = "3")private Integer num;@ExcelProperty("成色要求")@Schema(description = "成色要求", example = "足金999")private String qualityRequired;@ExcelProperty("字印要求")@Schema(description = "字印要求", example = "无")private String printContent;@ExcelProperty("下单时间")@Schema(description = "下单时间", example = "2023/1/7  15:12:13")private String createTime;@ExcelProperty("交期要求")@Schema(description = "交期要求", example = "2023/2/7  15:12:13")private String timeRequired;@ExcelProperty("预估克重")@Schema(description = "预估克重", example = "49.99")private String guessWeight;@ExcelProperty("备注")@Schema(description = "备注", example = "无备注")private String remark;
}

3.3 工具方法

注意：目前值考虑了 Integer与string的字段对象

public class ReflUtil extends ReflectUtil {/*** 反射获取对象并根据Schema注解的example进行值填充** @param tClass* @param <T>* @return* @throws Exception*/public static <T> T getInstanceFillAnnotationValue(Class<T> tClass) throws Exception {final T instance = tClass.newInstance();final Field[] fields = ReflectUtil.getFields(tClass);for (final Field field : fields) {final Class<?> filedType = field.getType();if (filedType != Integer.class && filedType != String.class) {continue;}final Schema annotation = field.getAnnotation(Schema.class);if (ObjUtil.isNull(annotation)) {continue;}final String example = annotation.example();field.setAccessible(true);field.set(instance, filedType == Integer.class ? Integer.valueOf(example) : example);}return instance;}
}