自己写了一个Java工具，是关于Excel导出(write)的，后续可能还会写导入(read)，因为太常用，所以分享出来
先是Annotation 两个
/** * @author Wang Yu */ @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) @Documented public @interface Excel { /** * @return Array of Cells's name */ String[] value(); } /** * @author Wang Yu * CreateAt 2019-10-31 14:44 */ @Target(ElementType.FIELD) @Retention(RetentionPolicy.RUNTIME) @Documented public @interface Cell { /** * @return the position of cell, start with 0 */ int value() default -1; }工具：
/** * @author Wang Yu * CreateAt 2019-10-31 15:08 */ public class ExcelUtil { private static final Logger LOG = Logger.getLogger(ExcelUtil.class); /** * create XSSFWorkbook by data * @param sheetName sheet name * @param data the data * @param clazz should use {@link Excel} * @return the XSSFWorkbook Object. Should close after use! */ public static <T> XSSFWorkbook createWorkbook(String sheetName, List<T> data, Class<T> clazz) { if (!clazz.isAnnotationPresent(Excel.class)) { throw new RuntimeException("Unable createWorkbook Object to excel, " + "Because: Class " + clazz.getSimpleName() + " doesn't assign from Excel.class"); } try { Excel excelAnnotation = clazz.getAnnotation(Excel.class); String[] cellsArray = excelAnnotation.value(); // create Cell Header XSSFWorkbook wb = new XSSFWorkbook(); XSSFSheet sheet = wb.createSheet(sheetName); XSSFRow headerRow = sheet.createRow(0); for (int i = 0; i < cellsArray.length; i++) { headerRow.createCell(i).setCellValue(cellsArray[i]); } // create Data Rows Field[] fields = clazz.getDeclaredFields(); for (int index = 0; index < data.size(); index++) { T object = data.get(index); // create a row XSSFRow dataRow = sheet.createRow(index + 1); // for each the fields int fieldIndex = 0; for (Field field : fields) { if (!field.isAnnotationPresent(Cell.class)) { continue; } String fieldName = field.getName(); Cell cellAnnotation = field.getAnnotation(Cell.class); int cellIndex = cellAnnotation.value(); if (cellIndex == -1) { cellIndex = fieldIndex; } XSSFCell cell = dataRow.createCell(cellIndex); String getter = InvokeUtil.getter(fieldName); try { Method getterMethod = clazz.getDeclaredMethod(getter); Object fieldValue = getterMethod.invoke(object); if (fieldValue == null) { cell.setCellValue(Constant.EMPTY_STR); } else if (field.getType().equals(String.class)) { cell.setCellValue((String) fieldValue); } else if (field.getType().equals(BigDecimal.class)) { BigDecimal bigDecimal = (BigDecimal) fieldValue; cell.setCellValue(bigDecimal.doubleValue()); } else if (field.getType().equals(Integer.class)) { cell.setCellValue((Integer) fieldValue); } else if (field.getType().equals(Long.class)) { cell.setCellValue((Long) fieldValue); } else if (field.getType().equals(Date.class)) { Date date = (Date) fieldValue; cell.setCellValue(DateFormatUtils.format(date, Constant.DATE_FORMAT)); } else { throw new RuntimeException("Unable convert type of : " + fieldName); } fieldIndex++; } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) { LOG.error("error occurs on ExcelUtil.createWorkbook(): ", e); } } } // end of for each data return wb; } catch (Exception e) { LOG.error("error occurs on ExcelUtil.createWorkbook() ", e); return null; } } }
