背景:在舊系統的基礎上,導出一些工單信息時,現需要新添加處理人的簽名或者簽章,這就涉及圖片的上傳、下載、寫入等幾個操作。
1、EasyExcel工具類
(1)支持下拉框的導出。
import com.alibaba.excel.EasyExcelFactory;
import com.alibaba.excel.ExcelWriter;
import com.alibaba.excel.write.builder.ExcelWriterBuilder;
import com.alibaba.excel.write.handler.SheetWriteHandler;
import com.alibaba.excel.write.handler.WriteHandler;
import com.alibaba.excel.write.metadata.WriteSheet;
import com.alibaba.excel.write.metadata.holder.WriteSheetHolder;
import com.alibaba.excel.write.metadata.holder.WriteWorkbookHolder;
import com..common.handler.DropDownHandler;
import com..modules.device.convert.ImageCellWriteHandler;
import com..modules.device.domain.vo.DeviceAndTypeVO;
import lombok.extern.slf4j.Slf4j;
import lombok.var;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFClientAnchor;import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.List;@Slf4j
public class ExcelExportUtil {private static final String CHARACTER = "UTF-8";private static final String CONTENT_TYPE = "application/vnd.ms-excel;charset=utf-8";private static final String CONTENT_DISPOSITION = "Content-Disposition";private static final String CACHE_CONTROL = "Cache-Control";private static final String NO_STORE = "no-store";private static final String MAX_AGE = "max-age=0";private static final String PASSWORD = "excel_unlock";private static final Integer colSplit = 0;private static final Integer rowSplit = 1;private static final Integer leftmostColumn = 0;private static final Integer topRow = 1;
/*** 通用導出 Excel 方法(支持下拉框和每行圖片插入)** @param response HttpServletResponse* @param data 導出數據,數據行順序與 Excel 中順序一致(表頭在第0行,第一條數據為第1行)* @param clazz 數據模型 Class* @param fileName 導出文件名(不包含后綴)* @param dropDownHandler 下拉框處理器(可選,可傳 null)* @param imagesList 每條記錄對應的圖片數據列表,List中每個元素為 byte[2] 數組,* 第0位為簽名圖片, 第1位為簽章圖片(可有可無)* @param signCol 簽名圖片插入列(0-based)* @param signatureCol 簽章圖片插入列(0-based)* @throws IOException I/O 異常時拋出*/public static void exportExcel(HttpServletResponse response, List<?> data, Class<?> clazz, String fileName,Object dropDownHandler, List<byte[][]> imagesList,int signCol, int signatureCol) throws IOException {String fullFileName = fileName + ".xlsx";String encodedFileName = URLEncoder.encode(fullFileName, StandardCharsets.UTF_8.toString());response.setCharacterEncoding(CHARACTER);response.setContentType(CONTENT_TYPE);response.setHeader(CONTENT_DISPOSITION, "attachment; filename=" + encodedFileName);response.setHeader(CACHE_CONTROL, NO_STORE);response.addHeader(CACHE_CONTROL, MAX_AGE);ServletOutputStream out = null;ExcelWriter excelWriter = null;try {out = response.getOutputStream();ExcelWriterBuilder writerBuilder = EasyExcelFactory.write(out, clazz);// 注冊下拉框處理器(需確保 dropDownHandler 是 WriteHandler 類型)if (dropDownHandler != null && dropDownHandler instanceof WriteHandler) {writerBuilder.registerWriteHandler((WriteHandler) dropDownHandler);}excelWriter = writerBuilder.build();WriteSheet writeSheet = EasyExcelFactory.writerSheet(fileName).build();excelWriter.write(data, writeSheet);// 獲取 Workbook 和 SheetWorkbook workbook = excelWriter.writeContext().writeWorkbookHolder().getWorkbook();Sheet sheet = workbook.getSheetAt(0);// 遍歷數據行插入圖片(從第1行開始)if (imagesList != null && !imagesList.isEmpty()) {for (int i = 0; i < data.size(); i++) {int targetRowIndex = i + 1; // 數據行從第1行開始if (i < imagesList.size()) {byte[][] images = imagesList.get(i);if (images != null) {insertImages(sheet, workbook, targetRowIndex, images, signCol, signatureCol);}}}}// 必須顯式調用 finish 確保數據寫入流excelWriter.finish();out.flush();} catch (Exception e) {throw new IOException("導出 Excel 失敗: " + e.getMessage(), e);} finally {// 手動關閉資源(注意順序:先關閉 excelWriter,再關閉流)if (excelWriter != null) {excelWriter.finish(); // finish() 包含關閉操作}if (out != null) {try {out.close();} catch (IOException e) {log.error("關閉輸出流異常: ", e);}}}}/*** 通用的圖片插入方法,在指定的 Excel 行中插入簽名和簽章圖片** @param sheet 目標 Sheet* @param workbook Excel Workbook* @param targetRow 目標行索引(0-based;表頭為0,第一條數據為1)* @param images byte[2] 數組,其中 images[0] 為簽名圖片,images[1] 為簽章圖片* @param signCol 簽名圖片插入列(0-based)* @param signatureCol 簽章圖片插入列(0-based)*/private static void insertImages(Sheet sheet, Workbook workbook, int targetRow, byte[][] images,int signCol, int signatureCol) {if (sheet == null || workbook == null) {return;}Row row = sheet.getRow(targetRow);if (row == null) {row = sheet.createRow(targetRow);}Drawing<?> drawing = sheet.createDrawingPatriarch();if (images[0] != null && images[0].length > 0) {int pictureIdx = workbook.addPicture(images[0], Workbook.PICTURE_TYPE_PNG);ClientAnchor anchor = new XSSFClientAnchor(0, 0, 1023, 255, signCol, targetRow, signCol + 1, targetRow + 1);drawing.createPicture(anchor, pictureIdx);}if (images[1] != null && images[1].length > 0) {int pictureIdx = workbook.addPicture(images[1], Workbook.PICTURE_TYPE_PNG);ClientAnchor anchor = new XSSFClientAnchor(0, 0, 1023, 255, signatureCol, targetRow, signatureCol + 1, targetRow + 1);drawing.createPicture(anchor, pictureIdx);}}
}
(2)無下拉框實現
/*** 配合insertImages(Sheet sheet, Workbook workbook, byte[] signImage, byte[] signatureImage,* int targetRowIndex, int signCol, int signatureCol) 方法使用* @param response* @param data* @param clazz* @param fileName* @param signImage* @param signatureImage* @param targetRow* @param signCol* @param signatureCol* @throws IOException*/public static void exportExcel(HttpServletResponse response, List<?> data, Class<?> clazz, String fileName,byte[] signImage, byte[] signatureImage,int targetRow, int signCol, int signatureCol) throws IOException {String encodedFileName = URLEncoder.encode(fileName + ".xlsx", "UTF-8");response.setCharacterEncoding("UTF-8");response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");response.setHeader("Content-Disposition", "attachment; filename=" + encodedFileName);response.setHeader("Cache-Control", "no-store");response.addHeader("Cache-Control", "max-age=0");ExcelWriter excelWriter = null;ServletOutputStream out = null;try {out = response.getOutputStream();excelWriter = EasyExcelFactory.write(out, clazz).build();WriteSheet writeSheet = EasyExcelFactory.writerSheet(fileName).build();excelWriter.write(data, writeSheet);// 獲取 Workbook 和 SheetWorkbook workbook = excelWriter.writeContext().writeWorkbookHolder().getWorkbook();Sheet sheet = workbook.getSheetAt(0);// 插入圖片insertImages(sheet, workbook, signImage, signatureImage, targetRow, signCol, signatureCol);// 必須顯式調用 finish 確保寫入完成excelWriter.finish();out.flush();} finally {// 手動關閉資源(EasyExcel 3.x 中 finish() 已包含關閉操作)if (excelWriter != null) {excelWriter.finish(); // 確保資源釋放}if (out != null) {out.close();}}}/*** 通用inserImages方法,和沒有的DropDownHandler dropDownHandler參數的exportExcel方法一起配合使用* @param sheet* @param workbook* @param signImage* @param signatureImage* @param targetRowIndex* @param signCol* @param signatureCol*/private static void insertImages(Sheet sheet, Workbook workbook, byte[] signImage, byte[] signatureImage,int targetRowIndex, int signCol, int signatureCol) {if (sheet == null || workbook == null) {log.warn("插入圖片失敗: sheet 或 workbook 為空");return;}// 確保目標行存在Row row = sheet.getRow(targetRowIndex);if (row == null) {row = sheet.createRow(targetRowIndex);}Drawing<?> drawing = sheet.createDrawingPatriarch();// 插入簽名圖片if (signImage != null && signImage.length > 0) {int pictureIdx = workbook.addPicture(signImage, Workbook.PICTURE_TYPE_PNG);ClientAnchor anchor = new XSSFClientAnchor(0, 0, 1023, 255, signCol, targetRowIndex, signCol + 1, targetRowIndex + 1);drawing.createPicture(anchor, pictureIdx);}// 插入簽章圖片if (signatureImage != null && signatureImage.length > 0) {int pictureIdx = workbook.addPicture(signatureImage, Workbook.PICTURE_TYPE_PNG);ClientAnchor anchor = new XSSFClientAnchor(0, 0, 1023, 255, signatureCol, targetRowIndex, signatureCol + 1, targetRowIndex + 1);drawing.createPicture(anchor, pictureIdx);}}
2、實體類和自定義轉換類
//使用自定義轉換器,寫入空內容,但表頭顯示“簽名”@ExcelProperty(value = "處理人簽名", converter = ImageHeaderConverter.class, index = 15)private byte[] signImage;// 使用自定義轉換器,寫入空內容,但表頭顯示“簽名”@ExcelProperty(value = "處理人簽章", converter = ImageHeaderConverter.class, index = 16)private byte[] signatureImage;/*** 自定義Converter*/
public class ImageHeaderConverter implements Converter<byte[]> {@Overridepublic Class supportJavaTypeKey() {return byte[].class;}@Overridepublic WriteCellData<?> convertToExcelData(byte[] value, ExcelContentProperty contentProperty, GlobalConfiguration globalConfiguration) {// 返回空數據,防止自動轉換報錯,但表頭信息仍會根據@ExcelProperty的value顯示return new WriteCellData<>("");}@Overridepublic CellDataTypeEnum supportExcelTypeKey() {return null;}public byte[] convertToJavaData(CellData cellData, ExcelContentProperty contentProperty, GlobalConfiguration globalConfiguration) {return new byte[0];}
}
3、根據圖片路徑下載圖片工具類
public class ImagesUtils {public static byte[] downloadImage(String imageUrl) {if (imageUrl == null || imageUrl.trim().isEmpty()) {log.warn("下載圖片失敗: imageUrl 為空");return null;}HttpURLConnection connection = null;try {URL url = new URL(imageUrl);connection = (HttpURLConnection) url.openConnection();connection.setRequestMethod("GET");connection.setConnectTimeout(10000); // 增加超時時間到10秒connection.setReadTimeout(10000);connection.setInstanceFollowRedirects(true); // 允許自動重定向// 檢查 HTTP 響應碼int statusCode = connection.getResponseCode();if (statusCode != HttpURLConnection.HTTP_OK) {log.warn("下載圖片失敗: {},HTTP狀態碼: {},響應消息: {}",imageUrl, statusCode, connection.getResponseMessage());return null;}try (InputStream inputStream = connection.getInputStream();ByteArrayOutputStream outputStream = new ByteArrayOutputStream()) {byte[] buffer = new byte[4096]; // 增大緩沖區提升讀取效率int bytesRead;while ((bytesRead = inputStream.read(buffer)) != -1) {outputStream.write(buffer, 0, bytesRead);}return outputStream.toByteArray();}} catch (Exception e) {log.warn("下載圖片失敗: {},錯誤類型: {},詳細信息: {}",imageUrl, e.getClass().getSimpleName(), e.getMessage(), e); // 輸出完整異常return null;} finally {if (connection != null) {connection.disconnect(); // 顯式斷開連接}}}
}
4、業務邏輯實現
// 1. 查詢 Channel_SIGN_SIGNATURE 表,獲取所有處理記錄List<ChannelSignSignature> processList = channelSignSignatureMapper.selectList(new LambdaQueryWrapper<ChannelSignSignature>().in(ChannelSignSignature::getDisposeChannelId, ids));if (CollectionUtils.isEmpty(processList)) {return ReposeResult.failed(ResultCode.CHANNEL_EXPORT_NULL);}//根據前端傳入的ids順序排序處理記錄Map<Long, ChannelSignSignature> processMap = processList.stream().collect(Collectors.toMap(ChannelSignSignature::getDisposeChannelId, Function.identity()));List<ChannelSignSignature> sortedProcessList = new ArrayList<>();for (Long id :ids) {if (!processMap.containsKey(id)) {return ReposeResult.failed("部分導出ID未保存處理記錄,請先處理記錄再導出");}sortedProcessList.add(processMap.get(id));}// 2. 獲取所有處理人姓名(保持原順序)List<String> userNames = sortedProcessList.stream().map(ChannelSignSignature::getChannelRecordName).collect(Collectors.toList());// 3. 批量查詢用戶信息(userId 映射表)Map<String, Long> userIdMap;if (CollectionUtils.isEmpty(userNames)) {userIdMap = new HashMap<>();} else {List<User> users = userMapper.selectList(new LambdaQueryWrapper<User>().in(User::getUsername, userNames));userIdMap = users.stream().collect(Collectors.toMap(User::getUsername, User::getId, (u1, u2) -> u1));}// 4. 查詢用戶簽名 & 簽章Map<Long, List<String>> signMap = new HashMap<>();Map<Long, List<String>> signatureMap = new HashMap<>();if (!userIdMap.isEmpty()) {// 4.1 批量查詢用戶簽名(userId -> 簽名列表)List<UserSign> userSigns = userSignMapper.selectList(new LambdaQueryWrapper<UserSign>().in(UserSign::getUserId, userIdMap.values()));signMap = userSigns.stream().collect(Collectors.groupingBy(UserSign::getUserId,LinkedHashMap::new,Collectors.mapping(UserSign::getContent, Collectors.toList())));// 4.2 批量查詢用戶簽章(userId -> 簽章列表)List<UserSignature> userSignatures = userSignatureMapper.selectList(new LambdaQueryWrapper<UserSignature>().in(UserSignature::getUserId, userIdMap.values()));signatureMap = userSignatures.stream().collect(Collectors.groupingBy(UserSignature::getUserId,LinkedHashMap::new,Collectors.mapping(UserSignature::getContent, Collectors.toList())));}Integer grading = UserUtils.getUser().getGrading();HashMap<Integer, String[]> dropDownMap = new HashMap<>();String[] results = Arrays.stream(ChannelResultEnum.values()).map(ChannelResultEnum::getDesc).toArray(String[]::new);dropDownMap.put(13, results);List<ChannelVO> channels = channelMapper.selectJoinList(ChannelVO.class, new MPJLambdaWrapper<>(DataChannel.class).selectAll(DataChannel.class).select(Dept::getDeptName).selectAs(Period::getDescription, "period").select(BenchInfo::getBench).selectCollection(MachineInfo.class, ChannelVO::getMachineInfos).leftJoin(ChannelModel.class, ChannelModel::getChannelId, DataChannel::getId).leftJoin(MachineInfo.class, MachineInfo::getId, ChannelModel::getModelId).leftJoin(Dept.class, Dept::getId, DataChannel::getDeptId).leftJoin(Period.class, Period::getId, DataChannel::getPeriodId).leftJoin(BenchInfo.class, BenchInfo::getId, DataChannel::getBenchId).ge(ObjectUtils.isNotEmpty(grading), DataChannel::getGrading, grading).in(DataChannel::getId, ids));channels.forEach(channelVO -> {List<String> models = channelVO.getMachineInfos().stream().map(MachineInfo::getModel).collect(Collectors.toList());channelVO.setModel(String.join(",", models));});//根據前端傳入的ids順序排序channelVOMap<Long, ChannelVO> channelVoMap= channels.stream().collect(Collectors.toMap(ChannelVO::getId, Function.identity()));List<ChannelVO> sortedChannelVOs = new ArrayList<>();for (Long id:ids) {if (!channelVoMap.containsKey(id)) {return ReposeResult.failed("部分導出ID未保存檢查記錄,請先保存處理記錄再導出");}sortedChannelVOs.add(channelVoMap.get(id));}List<ExportChannelDTO> exportChannelDTOS = CopyUtils.copyList(sortedChannelVOs, ExportChannelDTO.class);// 5. 按 `userNames` 生成 `signUrls` 和 `signatureUrls`(保證順序)List<String> signUrls = new ArrayList<>();List<String> signatureUrls = new ArrayList<>();for (String userName : userNames) {Long userId = userIdMap.get(userName);if (userId != null) {List<String> signs = signMap.getOrDefault(userId, Collections.emptyList());List<String> signatures = signatureMap.getOrDefault(userId, Collections.emptyList());// 如果有簽名,添加簽名;如果有簽章,添加簽章;如果都有,則都添加if (!signs.isEmpty()) {signUrls.addAll(signs);} else {signUrls.add(null);}if (!signatures.isEmpty()) {signatureUrls.addAll(signatures);} else {signatureUrls.add(null);}} else {// 處理人無簽名/簽章,則填充 nullsignUrls.add(null);signatureUrls.add(null);}}// 7. 賦值到 DTOfor (int i = 0; i < exportChannelDTOS.size(); i++) {ExportChannelDTO dto = exportChannelDTOS.get(i);// 取簽名圖片if (signUrls.get(i) != null) {dto.setSignImage(downloadImage(BASE_IMAGE_URL + signUrls.get(i)));} else {dto.setSignImage(null);}// 取簽章圖片if (signatureUrls.get(i) != null) {dto.setSignatureImage(downloadImage(BASE_IMAGE_URL + signatureUrls.get(i)));} else {dto.setSignatureImage(null);}}// 8. 構造圖片數據列表,與 checkDTOS 順序一致List<byte[][]> imagesList = exportChannelDTOS.stream().map(dto -> new byte[][]{dto.getSignImage() != null ? dto.getSignImage() : new byte[0],dto.getSignatureImage() != null ? dto.getSignatureImage() : new byte[0]}).collect(Collectors.toList());ExcelExportUtil.exportExcel(response,exportChannelDTOS,ExportChannelDTO.class,ConstantUtil.DATA_CHANNEL,new DropDownHandler(dropDownMap),imagesList,15,16);log.info("---導出數據通道信息完成---");
代碼不可直接使用,只是自己記錄一下,方便下次使用,你完全可以使用AI來幫你寫這些部分。