easyExcel中使用String类型去接收Date日期类型问题
easyExcel中使用String类型去接收Date日期类型问题
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- 1 问题复现
-
- 1 导出类
- 2 导出工具类
- 3 导出控制类
- 4 导出结果
- 2 问题排查
- 3 问题总结
在easyExcel导出表格过程中,错误的使用了String类型去接收日期类型,最后导致日期值转换错误.
1 问题复现
1 导出类
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Phone {
@Excel(name = "商品id", width = 15, orderNum = "10")
private int id;
@Excel(name = "更新时间", format = "yyyy-MM-dd HH:mm:ss", width = 25, orderNum = "20")
private Date updateTime;
// 本应该使用Date,此处错误使用String
@Excel(name = "创建时间", format = "yyyy-MM-dd HH:mm:ss" , width = 25, orderNum = "30")
private String createTime;
}
2 导出工具类
public class ExcelUtils {
/**
* excel 导出
*
* @param list 数据
* @param title 标题
* @param sheetName sheet名称
* @param pojoClass pojo类型
* @param fileName 文件名称
* @param response
*/
public static void exportExcel(List<?> list, String title, String sheetName, Class<?> pojoClass, String fileName, HttpServletResponse response) throws IOException {
defaultExport(list, pojoClass, fileName, response, new ExportParams(title, sheetName, ExcelType.XSSF));
}
/**
* 默认的 excel 导出
*
* @param list 数据
* @param pojoClass pojo类型
* @param fileName 文件名称
* @param response
* @param exportParams 导出参数
*/
private static void defaultExport(List<?> list, Class<?> pojoClass, String fileName, HttpServletResponse response, ExportParams exportParams) throws IOException {
Workbook workbook = ExcelExportUtil.exportExcel(exportParams, pojoClass, list);
downLoadExcel(fileName, response, workbook);
}
/**
* 下载
*
* @param fileName 文件名称
* @param response
* @param workbook excel数据
*/
private static void downLoadExcel(String fileName, HttpServletResponse response, Workbook workbook) throws IOException {
try {
response.setCharacterEncoding("UTF-8");
response.setHeader("content-Type", "application/vnd.ms-excel");
response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName + "." + ExcelTypeEnum.XLSX.getValue(), "UTF-8"));
workbook.write(response.getOutputStream());
} catch (Exception e) {
throw new IOException(e.getMessage());
}
}
/**
* Excel 类型枚举
*/
enum ExcelTypeEnum {
XLS("xls"), XLSX("xlsx");
private String value;
ExcelTypeEnum(String value) {
this.value = value;
}
public String getValue() {
return value;
}
}
}
3 导出控制类
@RequestMapping(value = "/export")
public void exportExcel(HttpServletResponse response) throws IOException {
// 获取当前日期
Date date = new Date();
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String format = simpleDateFormat.format(date);
// 模拟数据,真实场景从数据库获取
List<Phone> phoneDTOList = new ArrayList<>();
phoneDTOList.add(new Phone(6, date, format));
phoneDTOList.add(new Phone(10, date, format));
phoneDTOList.add(new Phone(20, date, format));
// 导出数据
ExcelUtils.exportExcel(phoneDTOList, "手机信息表", "手机信息", Phone.class, "手机信息", response);
}
4 导出结果
| 商品id | 更新时间 | 创建时间 |
|---|---|---|
| 6 | 2023-06-12 23:27:48 | 2022-12-05 23:02:23 |
| 10 | 2023-06-12 23:27:48 | 2022-12-05 23:02:23 |
| 20 | 2023-06-12 23:27:48 | 2022-12-05 23:02:23 |
从上面的导出结果可以得知,在Excel生成过程中,日期类型,被有规律的修改过,导致创建时间和更新时间不相等.
2 问题排查
从上述分析可知,easyExcel生成表格过程中,单元格的赋值转换过程中,一定不同的判断.OK, 我们跟着代码一起冲!
1 入口代码, 即我们调用工具类,并传入集合数据.
ExcelUtils.exportExcel(phoneDTOList, "手机信息表", "手机信息", Phone.class, "手机信息", response);
2 在下面方法时,传入了集合数据,并未返回,可知进入easyExcel源码里面.
private static void defaultExport(List<?> list, Class<?> pojoClass, String fileName, HttpServletResponse response, ExportParams exportParams) throws IOException {
Workbook workbook = ExcelExportUtil.exportExcel(exportParams, pojoClass, list);
downLoadExcel(fileName, response, workbook);
}
3 ExcelExportUtil类中该方法,可知第二步,创建sheet过程中传入了集合值.
/**
* @param entity 表格标题属性
* @param pojoClass Excel对象Class
* @param dataSet Excel对象数据List
*/
public static Workbook exportExcel(ExportParams entity, Class<?> pojoClass,
Collection<?> dataSet) {
Workbook workbook = getWorkbook(entity.getType(), dataSet.size());
new ExcelExportService().createSheet(workbook, entity, pojoClass, dataSet);
return workbook;
}
4 ExcelExportService类中该方法,可以看到是调用createSheetForMap方法时,传入了集合值.
public void createSheet(Workbook workbook, ExportParams entity, Class<?> pojoClass,
Collection<?> dataSet) {
// 省略...
try {
List<ExcelExportEntity> excelParams = new ArrayList<ExcelExportEntity>();
// 得到所有字段
Field[] fileds = PoiPublicUtil.getClassFields(pojoClass);
ExcelTarget etarget = pojoClass.getAnnotation(ExcelTarget.class);
String targetId = etarget == null ? null : etarget.value();
getAllExcelField(entity.getExclusions(), targetId, fileds, excelParams, pojoClass,
null, null);
//获取所有参数后,后面的逻辑判断就一致了
createSheetForMap(workbook, entity, excelParams, dataSet);
} catch (Exception e) {
LOGGER.error(e.getMessage(), e);
throw new ExcelExportException(ExcelExportEnum.EXPORT_ERROR, e.getCause());
}
}
5 进入了createSheetForMap方法, 调用insertDataToSheet方法,并传入集合值.
public void createSheetForMap(Workbook workbook, ExportParams entity,
List<ExcelExportEntity> entityList, Collection<?> dataSet) {
// 省略...
insertDataToSheet(workbook, entity, entityList, dataSet, sheet);
}
6 进入insertDataToSheet方法,对集合迭代器遍历,并调用了createCells方法,传入遍历值.
protected void insertDataToSheet(Workbook workbook, ExportParams entity,
List<ExcelExportEntity> entityList, Collection<?> dataSet,Sheet sheet) {
try {
// 省略...
Iterator<?> its = dataSet.iterator();
List<Object> tempList = new ArrayList<Object>();
while (its.hasNext()) {
Object t = its.next();
index += createCells(patriarch, index, t, excelParams, sheet, workbook, rowHeight, 0)[0];
tempList.add(t);
if (index >= MAX_NUM) {
break;
}
}
if (entity.getFreezeCol() != 0) {
sheet.createFreezePane(entity.getFreezeCol(), 0, entity.getFreezeCol(), 0);
}
mergeCells(sheet, excelParams, titleHeight);
its = dataSet.iterator();
for (int i = 0, le = tempList.size(); i < le; i++) {
its.next();
its.remove();
}
if (LOGGER.isDebugEnabled()) {
LOGGER.debug("List data more than max ,data size is {}",
dataSet.size());
}
// 发现还有剩余list 继续循环创建Sheet
if (dataSet.size() > 0) {
createSheetForMap(workbook, entity, entityList, dataSet);
} else {
// 创建合计信息
addStatisticsRow(getExcelExportStyler().getStyles(true, null), sheet);
}
} catch (Exception e) {
LOGGER.error(e.getMessage(), e);
throw new ExcelExportException(ExcelExportEnum.EXPORT_ERROR, e.getCause());
}
}
7 进入 createCells方法,调用getCellValue方法,并传入了遍历值.
public int[] createCells(Drawing patriarch, int index, Object t,
List<ExcelExportEntity> excelParams, Sheet sheet, Workbook workbook,
short rowHeight, int cellNum) {
try {
// 省略...
Object value = getCellValue(entity, t);
if (entity.getType() == BaseEntityTypeConstants.STRING_TYPE) {
createStringCell(row, cellNum++, value == null ? "" : value.toString(),
index % 2 == 0 ? getStyles(false, entity) : getStyles(true, entity),
entity);
} else if (entity.getType() == BaseEntityTypeConstants.DOUBLE_TYPE) {
createDoubleCell(row, cellNum++, value == null ? "" : value.toString(),
index % 2 == 0 ? getStyles(false, entity) : getStyles(true, entity),
entity);
} else {
createImageCell(patriarch, entity, row, cellNum++,
value == null ? "" : value.toString(), t);
}
if (entity.isHyperlink()) {
row.getCell(cellNum - 1)
.setHyperlink(dataHandler.getHyperlink(
row.getSheet().getWorkbook().getCreationHelper(), t,
entity.getName(), value));
}
}
}
// 省略...
return new int[]{maxHeight, cellNum};
} catch (Exception e) {
LOGGER.error("excel cell export error ,data is :{}", ReflectionToStringBuilder.toString(t));
LOGGER.error(e.getMessage(), e);
throw new ExcelExportException(ExcelExportEnum.EXPORT_ERROR, e);
}
}
8 进入getCellValue方法, 因为日期类型的Format不为空,我们在实体上设置了为format = "yyyy-MM-dd HH:mm:ss", 所以进入dateFormatValue方法.
public Object getCellValue(ExcelExportEntity entity, Object obj) throws Exception {
Object value;
// 省略...
if (StringUtils.isNotEmpty(entity.getFormat())) {
value = dateFormatValue(value, entity);
}
if (entity.getReplace() != null && entity.getReplace().length > 0) {
value = replaceValue(entity.getReplace(), String.valueOf(value));
}
if (StringUtils.isNotEmpty(entity.getNumFormat())) {
value = numFormatValue(value, entity);
}
if (StringUtils.isNotEmpty(entity.getDict()) && dictHandler != null) {
value = dictHandler.toName(entity.getDict(), obj, entity.getName(), value);
}
if (needHandlerList != null && needHandlerList.contains(entity.getName())) {
value = dataHandler.exportHandler(obj, entity.getName(), value);
}
if (StringUtils.isNotEmpty(entity.getSuffix()) && value != null) {
value = value + entity.getSuffix();
}
if (value != null && StringUtils.isNotEmpty(entity.getEnumExportField())) {
value = PoiReflectorUtil.fromCache(value.getClass()).getValue(value, entity.getEnumExportField());
}
return value == null ? "" : value.toString();
}
9 进入dateFormatValue方法, 看到第一个判断,value是否是String类型实例, 且不为空, 创建时间的类型都满足,所以进入第一个if判断,且ExcelExportEntity类中的databaseFormat数据库格式默认为yyyyMMddHHmmss, 创建时间2023-06-12 23:27:48进过了数据库默认时间格式的装换后变成的Date类型值为2022-12-05 23:02:23 , 最后一步,都经过自定义的Format,将日期类型,转换成字符串返回.
(ps: 更新时间的类型是Date,所以进入第二个if中, 直接赋值,没有进行日期的装换)
private Object dateFormatValue(Object value, ExcelExportEntity entity) throws Exception {
Date temp = null;
if (value instanceof String && StringUtils.isNoneEmpty(value.toString())) {
SimpleDateFormat format = new SimpleDateFormat(entity.getDatabaseFormat());
temp = format.parse(value.toString());
} else if (value instanceof Date) {
temp = (Date) value;
} else if (value instanceof Instant) {
Instant instant = (Instant) value;
temp = Date.from(instant);
} else if (value instanceof LocalDate) {
LocalDate localDate = (LocalDate) value;
temp = Date.from(localDate.atStartOfDay(ZoneId.systemDefault()).toInstant());
} else if (value instanceof LocalDateTime) {
LocalDateTime localDateTime = (LocalDateTime) value;
temp = Date.from(localDateTime.atZone(ZoneId.systemDefault()).toInstant());
} else if (value instanceof ZonedDateTime) {
ZonedDateTime zonedDateTime = (ZonedDateTime) value;
temp = Date.from(zonedDateTime.toInstant());
} else if (value instanceof OffsetDateTime) {
OffsetDateTime offsetDateTime = (OffsetDateTime) value;
temp = Date.from(offsetDateTime.toInstant());
} else if (value instanceof java.sql.Date) {
temp = new Date(((java.sql.Date) value).getTime());
} else if (value instanceof java.sql.Time) {
temp = new Date(((java.sql.Time) value).getTime());
} else if (value instanceof java.sql.Timestamp) {
temp = new Date(((java.sql.Timestamp) value).getTime());
}
if (temp != null) {
SimpleDateFormat format = new SimpleDateFormat(entity.getFormat());
if (StringUtils.isNotEmpty(entity.getTimezone())) {
format.setTimeZone(TimeZone.getTimeZone(entity.getTimezone()));
}
value = format.format(temp);
}
return value;
}
3 问题总结
通过上述问题排查,知道了问题最后生成的原因,解决方法也很明确,即将创建时间的字符串类型更换为Date日期类型,再次导出Excel,日期数据正确.
一个类型的错误使用,引发了一个不大不小的bug. 对于代码的修改和测试,还需要认真仔细,减少bug的出现.
本文到此结束,一天一个bug系列,不希望有下次! 拜拜了您嘞