<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>easyexcel</artifactId>
    <version>4.0.3</version>
</dependency>

響應(yīng)流處理 → ExcelWriter 構(gòu)建 → 樣式 & 列寬策略 → 數(shù)據(jù)寫入

@Slf4j
public class ExportTool {
    /**
     * 導(dǎo)出 Excel 文件（簡單導(dǎo)出）
     *
     * @param dataList  導(dǎo)出的數(shù)據(jù)列表
     * @param clazz     數(shù)據(jù)類型（Excel 實(shí)體類）
     * @param fileName  導(dǎo)出的文件名（不帶擴(kuò)展名）
     * @param <T>       數(shù)據(jù)泛型
     */
    public static <T> void exportExcel(List<T> dataList, Class<T> clazz, String fileName) {
        if (dataList == null || dataList.isEmpty()) {
            log.warn("[ExportTool] 導(dǎo)出數(shù)據(jù)為空: {}", fileName);
        }

        try {
            HttpServletResponse response = WebTool.getResponse();

            // 使用復(fù)用的響應(yīng)流設(shè)置方法
            setupResponse(response, fileName + ".xlsx");

            try (ServletOutputStream out = response.getOutputStream()) {
                // 簡單導(dǎo)出，不增加樣式或列寬限制
                EasyExcel.write(out, clazz)
                        .autoCloseStream(true)
                        .sheet("數(shù)據(jù)")
                        .doWrite(dataList);
            }

            log.info("[ExportTool] 導(dǎo)出成功: {}, 共 {} 條記錄", fileName, dataList.size());
        } catch (Exception e) {
            log.error("[ExportTool] 導(dǎo)出失敗: {}", fileName, e);
            throw new ServiceException("導(dǎo)出失敗，請(qǐng)稍后重試");
        }
    }

    /**
     * 導(dǎo)出 Excel 文件（帶表頭樣式）
     *
     * @param dataList 數(shù)據(jù)列表
     * @param clazz    數(shù)據(jù)類型（Excel 實(shí)體類）
     * @param fileName 導(dǎo)出文件名（包含 .xlsx）
     * @param <T>      數(shù)據(jù)類型
     */
    public static <T> void exportExcelWithStyle(List<T> dataList, Class<T> clazz, String fileName) {
        HttpServletResponse response = WebTool.getResponse();
        try {
            // 設(shè)置響應(yīng)頭
            setupResponse(response, fileName);

            // 獲取輸出流并防止 EasyExcel 關(guān)閉響應(yīng)流
            ServletOutputStream out = response.getOutputStream();
            NoCloseOutputStream noCloseOut = new NoCloseOutputStream(out);

            // 創(chuàng)建 ExcelWriter
            ExcelWriter excelWriter = EasyExcel.write(noCloseOut, clazz)
                    // 注冊(cè)樣式策略
                    .registerWriteHandler(new HorizontalCellStyleStrategy(createHeadStyle(), createContentStyle()))
                    // 注冊(cè)列寬自適應(yīng)策略
                    .registerWriteHandler(createAutoWidthStrategy())
                    .build();

            // 創(chuàng)建 Sheet
            WriteSheet writeSheet = EasyExcel.writerSheet("導(dǎo)出數(shù)據(jù)").build();

            // 寫入數(shù)據(jù)
            excelWriter.write(dataList, writeSheet);

            // 完成寫入
            excelWriter.finish();

            log.info("[ExportTool] 導(dǎo)出成功: {}", fileName);
        } catch (Exception e) {
            log.error("[ExportTool] 導(dǎo)出失敗: {}", fileName, e);
            throw new ServiceException("導(dǎo)出 Excel 失敗");
        }
    }

    /**
     * 設(shè)置 HttpServletResponse 響應(yīng)頭
     */
    private static void setupResponse(HttpServletResponse response, String fileName) throws Exception {
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
        response.setCharacterEncoding("utf-8");
        String encodedFileName = URLEncoder.encode(fileName, StandardCharsets.UTF_8.toString());
        response.setHeader("Content-Disposition", "attachment;filename=" + encodedFileName);
    }

    /**
     * 創(chuàng)建表頭樣式
     */
    private static WriteCellStyle createHeadStyle() {
        WriteCellStyle headStyle = new WriteCellStyle();

        // 設(shè)置白底（不填充顏色）
        headStyle.setFillForegroundColor(null);
        headStyle.setFillPatternType(FillPatternType.NO_FILL);

        // 設(shè)置字體
        WriteFont headFont = new WriteFont();
        headFont.setFontHeightInPoints((short) 11);
        headFont.setFontName("微軟雅黑");
        headFont.setBold(true);
        headFont.setColor(IndexedColors.PALE_BLUE.getIndex());
        headStyle.setWriteFont(headFont);

        // 設(shè)置居中與自動(dòng)換行
        headStyle.setHorizontalAlignment(HorizontalAlignment.CENTER);
        headStyle.setVerticalAlignment(VerticalAlignment.CENTER);
        headStyle.setWrapped(true);

        // 設(shè)置無邊框
        headStyle.setBorderLeft(BorderStyle.NONE);
        headStyle.setBorderRight(BorderStyle.NONE);
        headStyle.setBorderTop(BorderStyle.NONE);
        headStyle.setBorderBottom(BorderStyle.NONE);

        return headStyle;
    }

    /**
     * 創(chuàng)建內(nèi)容樣式
     */
    private static WriteCellStyle createContentStyle() {
        WriteCellStyle contentStyle = new WriteCellStyle();

        // 設(shè)置字體
        WriteFont contentFont = new WriteFont();
        contentFont.setFontHeightInPoints((short) 11);
        contentFont.setFontName("等線");
        contentStyle.setWriteFont(contentFont);

        // 內(nèi)容右對(duì)齊，垂直居中，自動(dòng)換行
        contentStyle.setHorizontalAlignment(HorizontalAlignment.RIGHT);
        contentStyle.setVerticalAlignment(VerticalAlignment.CENTER);
        contentStyle.setWrapped(true);

        return contentStyle;
    }

    /**
     * 列寬自適應(yīng)策略（根據(jù)內(nèi)容長度自動(dòng)調(diào)整列寬，限制最小 15、最大 20 字符）
     */
    private static AbstractColumnWidthStyleStrategy createAutoWidthStrategy() {
        return new AbstractColumnWidthStyleStrategy() {
            private final Map<Integer, Integer> columnWidthMap = new HashMap<>();

            @Override
            protected void setColumnWidth(WriteSheetHolder writeSheetHolder,
                                          List<WriteCellData<?>> cellDataList,
                                          Cell cell,
                                          Head head,
                                          Integer relativeRowIndex,
                                          Boolean isHead) {
                if (cell == null || cell.getCellType() != CellType.STRING) return;
                String value = cell.getStringCellValue();
                if (value == null) return;

                Sheet sheet = writeSheetHolder.getSheet();
                int columnIndex = cell.getColumnIndex();

                // 根據(jù) UTF-8 字節(jié)長度計(jì)算列寬
                int length = value.getBytes(StandardCharsets.UTF_8).length;
                int minWidth = 15 * 256;
                int maxWidth = 20 * 256;
                int width = Math.max(minWidth, Math.min(length * 256 + 200, maxWidth));

                // 如果當(dāng)前列寬大于記錄的最大寬度，則更新列寬
                Integer maxWidthRecorded = columnWidthMap.getOrDefault(columnIndex, 0);
                if (width > maxWidthRecorded) {
                    columnWidthMap.put(columnIndex, width);
                    sheet.setColumnWidth(columnIndex, width);
                }

                // 設(shè)置自動(dòng)換行樣式
                CellStyle style = sheet.getWorkbook().createCellStyle();
                style.cloneStyleFrom(cell.getCellStyle());
                style.setWrapText(true);
                cell.setCellStyle(style);
            }
        };
    }

    /**
     * 包裝 Servlet 輸出流，不關(guān)閉底層流
     */
    public static class NoCloseOutputStream extends FilterOutputStream {
        public NoCloseOutputStream(OutputStream out) {
            super(out);
        }

        @Override
        public void close() throws IOException {
            flush(); // 不關(guān)閉底層流，僅刷新
        }
    }
}

public static <T> void exportExcel(List<T> dataList, Class<T> clazz, String fileName)

public static <T> void exportExcelWithStyle(List<T> dataList, Class<T> clazz, String fileName)

WriteCellStyle headStyle = createHeadStyle();

WriteCellStyle contentStyle = createContentStyle();

AbstractColumnWidthStyleStrategy autoWidthStrategy = createAutoWidthStrategy();

public static class NoCloseOutputStream extends FilterOutputStream

ExcelWriter excelWriter = EasyExcel.write(noCloseOut, clazz)
        .registerWriteHandler(styleStrategy)
        .registerWriteHandler(autoWidthStrategy)
        .build();

@Data
@AllArgsConstructor
@NoArgsConstructor
public class ExportUserVO {

    @ExcelProperty("姓名")
    private String userName;

    @ExcelProperty("ID")
    private Long id;

    @ExcelProperty("使用個(gè)數(shù)")
    private Integer useCount;

}

@GetMapping("/export")
public void exportUserExcel(HttpServletResponse response) {
    List<ExportUserVO> exportList = Arrays.asList(
        new ExportUserVO("張三", 1001L, 5),
        new ExportUserVO("李四", 1002L, 3)
    );

    String fileName = "用戶導(dǎo)出.xlsx";

    ExportTool.exportExcelWithStyle(response, exportList, ExportUserVO.class, fileName);
}