通过java将数据导出为PDF，包扣合并单元格操作

最近项目中需要将查询出来的表格数据以PDF形式导出，并且表格的形式包含横向行与纵向列的单元格合并操作，导出的最终效果如图所示：

首先引入操作依赖

<!--导出pdf所需包--><dependency><groupId>com.itextpdf</groupId><artifactId>itextpdf</artifactId><version>5.5.10</version></dependency><dependency><groupId>com.itextpdf</groupId><artifactId>itext-asian</artifactId><version>5.2.0</version></dependency>

最上面的基本信息是固定死的就是4*4的表格，这个创建起来 就比较简单，主要是下面这个表格，需要从数据库查出数据并循环进行展示，并且内容相同的列要进行合并。直接展示代码：

主类对外调用方法：

@Operation(summary = "导出PDF")@PostMapping("/download")@SneakyThrows(Exception.class)public void download(Long id,HttpServletResponse response, HttpServletRequest request) {// 防止日志记录获取session异常request.getSession();// 设置编码格式response.setContentType("application/pdf;charset=UTF-8");response.setCharacterEncoding("utf-8");String fileName = URLEncoder.encode("调试PDF", "UTF-8");response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".pdf");contractDemandThreeRequestBaseService.download(id,response);}

具体实现类：

@Overridepublic void download(Long id, HttpServletResponse response) {//要下载的数据查询数据部分我去掉了有需要自己根据业务取ContractDemandThreeRequestBaseDO baseDO = contractDemandThreeRequestBaseMapper.selectById(id);ContractDemandThreeRequestBaseRespVO base = ContractDemandThreeRequestBaseConvert.INSTANCE.convert(baseDO);base.setDeptName(ObjectUtil.isEmpty(deptService.getDept(base.getDeptId())) ? null : deptService.getDept(base.getDeptId()).getName());base.setProjectLeaderName(ObjectUtil.isEmpty(userService.getUser(base.getProjectLeaderId())) ? null : userService.getUser(base.getProjectLeaderId()).getNickname());//子表数据List<ContractDemandThreeQuestionDO> details = contractDemandThreeQuestionMapper.selectList(Wrappers.lambdaQuery(ContractDemandThreeQuestionDO.class).eq(ContractDemandThreeQuestionDO::getDemandId, id));//下面进行表格的创建、字体设置、合并单元格// 定义全局的字体静态变量Font titlefont;Font headfont;Font keyfont = null;Font textfont = null;Font content = null;BaseFont bfChinese = null;// 最大宽度try {// 不同字体（这里定义为同一种字体：包含不同字号、不同style）这里我用的最后一个                content字体bfChinese = BaseFont.createFont("STSong-Light", "UniGB-UCS2-H", BaseFont.NOT_EMBEDDED);titlefont = new Font(bfChinese, 16, Font.BOLD);headfont = new Font(bfChinese, 14, Font.BOLD);keyfont = new Font(bfChinese, 10, Font.BOLD);textfont = new Font(bfChinese, 15, Font.NORMAL);content = new Font(bfChinese, 10, Font.NORMAL);} catch (Exception e) {e.printStackTrace();}BaseFont bf;Font font = null;try {//创建字体bf = BaseFont.createFont("STSong-Light", "UniGB-UCS2-H",BaseFont.NOT_EMBEDDED);//使用字体并给出颜色font = new Font(bf, 20, Font.BOLD, BaseColor.BLACK);} catch (Exception e) {e.printStackTrace();}Document document = new Document();try {PdfWriter pdfWriter = PdfWriter.getInstance(document, response.getOutputStream());//打开生成的pdf文件document.open();//设置内容Paragraph paragraph = new Paragraph("采购需求三问", font);paragraph.setAlignment(1);//引用字体document.add(paragraph);// 设置表格的列宽和列数float[] widths = {25f, 25f, 25f, 25f};PdfPTable table = new PdfPTable(widths);table.setSpacingBefore(20f);// 设置表格宽度为100%table.setWidthPercentage(100.0F);table.setHeaderRows(1);table.getDefaultCell().setHorizontalAlignment(1);PdfPCell cell = null;//第一行：表格的名字cell = new PdfPCell(new Paragraph("采购项目名称", content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);cell.setFixedHeight(30);table.addCell(cell);//表格里面的值（下面都是同样的操作）cell = new PdfPCell(new Paragraph(base.getProjectName(), content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);table.addCell(cell);//第二行cell = new PdfPCell(new Paragraph("项目编号", content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);cell.setFixedHeight(30);table.addCell(cell);cell = new PdfPCell(new Paragraph(base.getProjectCode(), content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);table.addCell(cell);cell = new PdfPCell(new Paragraph("资金类型", content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);table.addCell(cell);cell = new PdfPCell(new Paragraph(getDitcValue("FundType", base.getFundType()), content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);table.addCell(cell);//第三行cell = new PdfPCell(new Paragraph("支出类别", content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);cell.setFixedHeight(30);table.addCell(cell);cell = new PdfPCell(new Paragraph(getDitcValue("ExpenditureCategory", base.getExpenditureCategory()), content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);table.addCell(cell);cell = new PdfPCell(new Paragraph("预算含税总金额（万元）", content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);table.addCell(cell);cell = new PdfPCell(new Paragraph(String.valueOf(base.getBudgetIncludingTaxTotalMoney()), content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);table.addCell(cell);//第三行cell = new PdfPCell(new Paragraph("采购内容", content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);cell.setFixedHeight(30);table.addCell(cell);cell = new PdfPCell(new Paragraph(base.getProcureContent(), content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);table.addCell(cell);//第四行cell = new PdfPCell(new Paragraph("需求部门", content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);cell.setFixedHeight(30);table.addCell(cell);cell = new PdfPCell(new Paragraph(base.getDeptName(), content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);table.addCell(cell);cell = new PdfPCell(new Paragraph("项目负责人", content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);cell.setFixedHeight(30);table.addCell(cell);cell = new PdfPCell(new Paragraph(base.getProjectLeaderName(), content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);table.addCell(cell);// 设置表格的列宽和列数float[] widths2 = {25f, 25f, 25f};PdfPTable table2 = new PdfPTable(widths2);table2.setSpacingBefore(20f);// 设置表格宽度为100%table2.setWidthPercentage(100.0F);table2.setHeaderRows(1);table2.getDefaultCell().setHorizontalAlignment(1);//需求三问详情信息标题栏cell = new PdfPCell(new Paragraph("需求三问", content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);cell.setFixedHeight(20);table2.addCell(cell);cell = new PdfPCell(new Paragraph("选择项", content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);table2.addCell(cell);cell = new PdfPCell(new Paragraph("内容项", content));cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);table2.addCell(cell);//下面的代码就是样图中底下的表格，需要动态构建数据//人员列表数据-第五行List<List<String>> doList = new ArrayList<>();if (CollectionUtils.isNotEmpty(details)) {//组装数据for (ContractDemandThreeQuestionDO detail : details) {String natureType = "项目" + getDitcValue("QuestionType", detail.getDemandNatureType());String deviceGoodsType = getDitcValue(baseDO.getModelType(), detail.getItemValue());doList.add(Arrays.asList(natureType, deviceGoodsType, detail.getItemContent()));}makeData(doList, content, table2);//为两个表格添加标题document.add(new Paragraph("\n"));document.add(new Paragraph("▋ 基本信息", content));document.add(new Paragraph("\n"));document.add(table);document.add(new Paragraph("\n"));document.add(new Paragraph("▋ 采购需求三问内容", content));document.add(new Paragraph("\n"));//将table2中数据相同的列合并单元格（横向合并）document.add(table2);// 加水印（水印组成：下载人姓名-手机号-部门）PdfContentByte waterMar = pdfWriter.getDirectContentUnder();AtomicReference<String> text = new AtomicReference<>("");Long loginUserId = getLoginUserId();AdminUserRedisVO adminUserRedisVO = adminUserRedisDAO.get(loginUserId);Optional.ofNullable(adminUserRedisVO).ifPresent(vo -> {DeptDO dept = deptService.getDept(adminUserRedisVO.getDeptId());String deptName = Objects.nonNull(dept) ? dept.getName() : "";text.set(vo.getNickname() + "-" + vo.getMobile() + "-" + deptName);});addTextFullWaterMark(waterMar, text.get(), bfChinese);//关闭文档document.close();} catch (DocumentException | IOException e) {e.printStackTrace();log.error("导出pdf失败:{}", e);}}

补充说明：List<List<String>> doList = new ArrayList<>();

这个是我构建底下表格数据的格式，举个例子，类似于：

List<List<String>> headList = new ArrayList<>();
headList.add(Arrays.asList(new String[]{"1", "2", "3"}));
headList.add(Arrays.asList(new String[]{"2", "6", "10"}));
headList.add(Arrays.asList(new String[]{"1", "12", "13"}));
headList.add(Arrays.asList(new String[]{"2", "9", "11"}));
headList.add(Arrays.asList(new String[]{"1", "8", "12"}));

根据自己的实际业务构建，我底下的表格是一个n*3的表格，只有三列，所以数据结构就相当于上面的两层List结构，最外层的集合代表有多少行，嵌套的结合相当于多少列（这里就是三列）,我将对象集合查询出来后使用循环，将我所用到的数据组装成这个示例的样子。

重点来了，以下是合并单元格的方法：

makeData(doList, content, table2);

/*** 合并单元格方法** @param list        表头数据  list中相连下标位置内容如果相同自动合并 上下位置内容相同自动合并* @param fontChinese 支持转换中文的Font对象* @return*/private void makeData(List<List<String>> list, Font fontChinese, PdfPTable table2) {List<List<PdfPCell>> aa = new ArrayList<>();int length = list.get(0).size();//循环在外层，这里代表的是有几列（其实是固定的，因为上面构建的时候，列数就是三列）//下面的循环不用管，是将你组装的数据设置到单元格里for (int i = 0; i < list.size(); i++) {List<String> strings = list.get(i);int colNum = 1;List<PdfPCell> bb = new ArrayList<>();for (int j = 0; j < strings.size(); j++) {if (j + 1 < strings.size()) {if (strings.get(j).equals(strings.get(j + 1))) {colNum++;} else {PdfPCell cell = new PdfPCell();//合并列cell.setColspan(colNum);Paragraph elements = new Paragraph(strings.get(j), fontChinese);elements.setAlignment(1);cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);cell.setFixedHeight(30);cell.addElement(elements);bb.add(cell);for (int a = 1; a < colNum; a++) {bb.add(null);}colNum = 1;}} else {PdfPCell cell = new PdfPCell();cell.setColspan(colNum);Paragraph elements = new Paragraph(strings.get(j), fontChinese);cell.setVerticalAlignment(Element.ALIGN_MIDDLE);cell.setHorizontalAlignment(Element.ALIGN_CENTER);elements.setAlignment(1);cell.setFixedHeight(30);cell.addElement(elements);bb.add(cell);for (int a = 1; a < colNum; a++) {bb.add(null);}colNum = 1;}}aa.add(bb);}//合并算法for (int i = 0; i < length; i++) {int rowSpan = 1;for (int j = 0; j < aa.size(); j++) {if (aa.get(j).get(i) == null) {continue;}if (j + 1 < aa.size()) {if (aa.get(j + 1).get(i) != null&& aa.get(j).get(i).getCompositeElements().get(0).toString().equals(aa.get(j + 1).get(i).getCompositeElements().get(0).toString())) {rowSpan++;} else {aa.get(j - rowSpan + 1).get(i).setRowspan(rowSpan);for (int a = 1; a < rowSpan; a++) {aa.get(j - rowSpan + 1 + a).set(i, null);}rowSpan = 1;}} else {aa.get(j - rowSpan + 1).get(i).setRowspan(rowSpan);for (int a = 1; a < rowSpan; a++) {aa.get(j - rowSpan + 1 + a).set(i, null);}rowSpan = 1;}}break;}for (List<PdfPCell> a : aa) {for (PdfPCell pCell : a) {if (pCell != null) {table2.addCell(pCell);}}}}

这里将合并算法进行一个说明：外层循环其实还就是表示列，我这里是三列，他会依次循环三列，并将横向与纵向的表格中有相同数据的都进行合并，也就是值相同的行进行合并，值相同的列也进行合并。但我的业务要求就是只合并第一列，所以我这里也没有改算法，偷了个懒，直接在第一次循环后加了break，直接终止后面的循环。这个自己看自己的业务要求。代码里的getDictValue方法是我自己获取字典值的方法，可自行定义

加水印：

public static void addTextFullWaterMark(PdfContentByte waterMar, String text, BaseFont bf) {waterMar.beginText();PdfGState gs = new PdfGState();// 设置填充字体不透明度为0.2fgs.setFillOpacity(0.2f);waterMar.setFontAndSize(bf, 20);// 设置透明度waterMar.setGState(gs);// 设置水印对齐方式 水印内容 X坐标 Y坐标 旋转角度for (int x = 0; x <= 900; x += 200) {for (int y = -50; y <= 800; y += 200) {waterMar.showTextAligned(Element.ALIGN_RIGHT, text, x, y, 35);}}// 设置水印颜色waterMar.setColorFill(BaseColor.GRAY);//结束设置waterMar.endText();waterMar.stroke();}

这个操作PDF的类很强大，基本上你想怎么导出，都可以进行调整