导出Excel，支持最佳

列表信息导出为Excel文件，

依赖pom：

Sheet, Row:<dependency><groupId>org.apache.poi</groupId><artifactId>poi</artifactId>
</dependency>XSSFWorkbook
<dependency><groupId>org.apache.poi</groupId><artifactId>poi-ooxml</artifactId>
</dependency>

实现代码： 

override表示是否覆盖现有文件，false，追加；true，覆盖。

private <T> void exportExcelToLocal(List<T> list, Class<T> clazz) throws IOException {if (CollectionUtils.isEmpty(list)) {return;}XSSFWorkbook workbook = null;File file = new File("src/main/resources/xxx.xlsx");FileInputStream fis = null;if (!file.exists()) {file.createNewFile();} else {if (!override) {fis = new FileInputStream(file);workbook = new XSSFWorkbook(fis);}}XSSFWorkbook workbookResult = ExcelUtils.exportExcelData(new XSSFWorkbook(), list, clazz, false);if (Objects.nonNull(workbook)) {Integer index = workbookResult.getSheetAt(0).getLastRowNum() + 1;Sheet sheet = workbookResult.getSheetAt(0);Sheet lastSheet = workbook.getSheetAt(0);for (int i = 1; i <= lastSheet.getLastRowNum(); ++i) {Row row = sheet.createRow(index++);for (int cellIndex = 0; cellIndex < lastSheet.getRow(i).getLastCellNum(); ++cellIndex) {String value = lastSheet.getRow(i).getCell(cellIndex).getStringCellValue();row.createCell(cellIndex).setCellValue(value);}}}FileOutputStream fos = new FileOutputStream(file);workbookResult.write(fos);fos.flush();fos.close();if (Objects.nonNull(fis)) {fis.close();}}

ExcelUtils：

单次导出操作

public static <T> XSSFWorkbook exportExcelData(XSSFWorkbook workbook, List<T> data, Class<T> clazz, boolean template) {XSSFSheet sheet = workbook.createSheet();Row rowHeader = sheet.createRow(0);Map<Integer, Field> fieldMap = analysisAnnotation(clazz);for(int i = 0; i < fieldMap.size(); ++i) {Cell cell = rowHeader.createCell(i);Field field = (Field)fieldMap.get(i + 1);ExcelBind ea = (ExcelBind)field.getAnnotation(ExcelBind.class);cell.setCellValue(ea.columnName());cell.setCellStyle(setRowHeaderStyle(workbook));cell.setCellType(CellType.STRING);}if (!template) {analysisData(sheet, data, clazz, fieldMap);}return workbook;}// 数据导出
private static <T> void analysisData(Sheet sheet, List<T> data, Class<T> clazz, Map<Integer, Field> fieldMap) {for(int i = 0; i < data.size(); ++i) {Row row = sheet.createRow(i + 1);T t = data.get(i);Class<?> aClass = t.getClass();for(int j = 0; j < fieldMap.size(); ++j) {Field declaredField = (Field)fieldMap.get(j + 1);declaredField.setAccessible(true);String key = declaredField.getName();Object value = "";try {value = declaredField.get(t) == null ? "" : declaredField.get(t);} catch (IllegalAccessException var13) {var13.printStackTrace();}if ("java.util.Date".equals(declaredField.getType().getName())) {ExcelBind ea = (ExcelBind)declaredField.getAnnotation(ExcelBind.class);if (StringUtils.isNotEmpty(ea.dateFormat())) {value = (new SimpleDateFormat(ea.dateFormat())).format(value);}}row.createCell(j).setCellValue(value.toString());}}}