itextpdf解决PDF合并的问题

╰半橙微兮° 2023-07-15 13:19 7阅读 0赞

## 首先是itextpdf的依赖 ##

<dependency>
        <groupId>com.itextpdf</groupId>
        <artifactId>itextpdf</artifactId>
        <version>5.5.10</version>
    </dependency>

## 后台生成一个PDF ##

import java.io.ByteArrayOutputStream;
    
    import com.model.User;
    import com.itextpdf.text.BaseColor;
    import com.itextpdf.text.Document;
    import com.itextpdf.text.DocumentException;
    import com.itextpdf.text.Element;
    import com.itextpdf.text.Font;
    import com.itextpdf.text.Paragraph;
    import com.itextpdf.text.pdf.BaseFont;
    import com.itextpdf.text.pdf.PdfContentByte;
    import com.itextpdf.text.pdf.PdfPCell;
    import com.itextpdf.text.pdf.PdfPTable;
    import com.itextpdf.text.pdf.PdfReader;
    import com.itextpdf.text.pdf.PdfWriter;
    import com.itextpdf.text.pdf.parser.PdfReaderContentParser;
    
    public class ReportKit {
    
         public static byte[] createReport(User user) throws Exception {
    
                   ByteArrayOutputStream ba = new ByteArrayOutputStream();
    
                   Document doc = new Document();//创建一个document对象
                   PdfWriter writer = PdfWriter.getInstance(doc, ba);//这个PdfWriter会一直往文档里写内容。
                  doc.open();//开启文档
    
                  BaseFont bfChinese = BaseFont.createFont("c://windows//fonts//msyh.TTF", BaseFont.IDENTITY_H, BaseFont.NOT_EMBEDDED);
    
                  com.itextpdf.text.Font FontChinese18 = new com.itextpdf.text.Font(bfChinese, 18, com.itextpdf.text.Font.BOLD);
                  com.itextpdf.text.Font FontChinese12 = new com.itextpdf.text.Font(bfChinese, 12, com.itextpdf.text.Font.NORMAL);
                  com.itextpdf.text.Font FontChinese11 = new com.itextpdf.text.Font(bfChinese, 11, com.itextpdf.text.Font.ITALIC);
    
                  Font fontChinese =  new  Font(bfChinese  ,  12 , Font.NORMAL, BaseColor.BLACK);
                  Paragraph pf = new Paragraph("");
    
                  //加入空行
                  Paragraph blankRow1 = new Paragraph(24f," ",FontChinese18);
                  doc.add(blankRow1);
    
                  //table2
                  PdfPTable table25 = new PdfPTable(2);
                  //设置每列宽度比例
                  int width21[] = {2,98};
                  table25.setWidths(width21);
                  table25.getDefaultCell().setBorder(0);
                  PdfPCell cell25 = new PdfPCell(new Paragraph("这是一个报告",FontChinese18));
                  cell25.setBorder(0);
                  table25.addCell("");
                  table25.addCell(cell25);
                  doc.add(table25);
    
                  Paragraph blankRow3 = new Paragraph(18f, "Report ", FontChinese11);
                  blankRow3.setAlignment(PdfContentByte.ALIGN_RIGHT);
                  doc.add(blankRow3);        
    
                  BaseColor lightGrey = new BaseColor(0xCC,0xCC,0xCC);
                  PdfPTable table8 = new PdfPTable(6);
    
                //设置table的宽度为100%
                table8.setWidthPercentage(100);
                //设置不同列的宽度
                float[] columnWidths = {1.6f, 1.6f, 1.6f, 1.6f, 1.6f, 1.6f};
                table8.setWidths(columnWidths);
                  PdfPCell cell1 = new PdfPCell(new Paragraph("用户名",FontChinese12));
                PdfPCell cell2 = new PdfPCell(new Paragraph("出生日期",FontChinese12));
                PdfPCell cell3 = new PdfPCell(new Paragraph("性别",FontChinese12));
                PdfPCell cell4 = new PdfPCell(new Paragraph("身高",FontChinese12));
                PdfPCell cell5 = new PdfPCell(new Paragraph("体重",FontChinese12));
                PdfPCell cell6 = new PdfPCell(new Paragraph("地区",FontChinese12));
                PdfPCell cell7 = new PdfPCell(new Paragraph(user.getAccessname(),FontChinese12));
                PdfPCell cell8 = new PdfPCell(new Paragraph(user.getBirthday(),FontChinese12));
                PdfPCell cell9 = new PdfPCell(new Paragraph(sex,FontChinese12));
                PdfPCell cell10 = new PdfPCell(new Paragraph(String.valueOf(user.getHeight()),FontChinese12));
                PdfPCell cell11 = new PdfPCell(new Paragraph(String.valueOf(user.getWeight()),FontChinese12));
                PdfPCell cell12 = new PdfPCell(new Paragraph(user.getArea_name(),FontChinese12));
    
                //表格高度
                cell1.setFixedHeight(30);
                cell2.setFixedHeight(30);
                cell3.setFixedHeight(30);
                cell4.setFixedHeight(30);
                cell5.setFixedHeight(30);
                cell6.setFixedHeight(30);
                cell7.setFixedHeight(30);
                cell8.setFixedHeight(30);
                cell9.setFixedHeight(30);
                cell10.setFixedHeight(30);
                cell11.setFixedHeight(30);
                cell12.setFixedHeight(30);
    
                //水平居中
               cell1.setHorizontalAlignment(Element.ALIGN_CENTER);
                cell2.setHorizontalAlignment(Element.ALIGN_CENTER);
                cell3.setHorizontalAlignment(Element.ALIGN_CENTER);
                cell4.setHorizontalAlignment(Element.ALIGN_CENTER);
                cell5.setHorizontalAlignment(Element.ALIGN_CENTER);
                cell6.setHorizontalAlignment(Element.ALIGN_CENTER);
                cell7.setHorizontalAlignment(Element.ALIGN_CENTER);
                cell8.setHorizontalAlignment(Element.ALIGN_CENTER);
                cell9.setHorizontalAlignment(Element.ALIGN_CENTER);
                cell10.setHorizontalAlignment(Element.ALIGN_CENTER);
                cell11.setHorizontalAlignment(Element.ALIGN_CENTER);
                cell12.setHorizontalAlignment(Element.ALIGN_CENTER);
    
                //垂直居中
                cell1.setVerticalAlignment(Element.ALIGN_MIDDLE);
                cell2.setVerticalAlignment(Element.ALIGN_MIDDLE);
                cell3.setVerticalAlignment(Element.ALIGN_MIDDLE);
                cell4.setVerticalAlignment(Element.ALIGN_MIDDLE);
                cell5.setVerticalAlignment(Element.ALIGN_MIDDLE);
                cell6.setVerticalAlignment(Element.ALIGN_MIDDLE);
                cell7.setVerticalAlignment(Element.ALIGN_MIDDLE);
                cell8.setVerticalAlignment(Element.ALIGN_MIDDLE);
                cell9.setVerticalAlignment(Element.ALIGN_MIDDLE);
                cell10.setVerticalAlignment(Element.ALIGN_MIDDLE);
                cell11.setVerticalAlignment(Element.ALIGN_MIDDLE);
                cell12.setVerticalAlignment(Element.ALIGN_MIDDLE);
    
                //边框颜色
                cell1.setBorderColor(lightGrey);
                cell2.setBorderColor(lightGrey);
                cell3.setBorderColor(lightGrey);
                cell4.setBorderColor(lightGrey);
                cell5.setBorderColor(lightGrey);
                cell6.setBorderColor(lightGrey);
                cell7.setBorderColor(lightGrey);
                cell8.setBorderColor(lightGrey);
                cell9.setBorderColor(lightGrey);
                cell10.setBorderColor(lightGrey);
                cell11.setBorderColor(lightGrey);
                cell12.setBorderColor(lightGrey);
    
                table8.addCell(cell1);
                table8.addCell(cell2);
                table8.addCell(cell3);
                table8.addCell(cell4);
                table8.addCell(cell5);
                table8.addCell(cell6);
                table8.addCell(cell7);
                table8.addCell(cell8);
                table8.addCell(cell9);
                table8.addCell(cell10);
                table8.addCell(cell11);
                table8.addCell(cell12);        
                doc.add(table8);
    
                doc.close();//（有开启文档，就要记得关闭文档）
                writer.close();
    
                byte[] bytes = ba.toByteArray();          
                return bytes;
         }
    }

到这里，调用这个方法，就可以获得这个文档的字节数组了。   
接下来开始拼接PDF。因为是结合前端页面实现的。因此这个方法是我在controller完成的。

//注意这里的produces，“application/pdf”，正是因为设置了这个,使得整个方法会将文档以PDF的格式返回到页面。
    @RequestMapping(value = "/newPdf/{report_name}", produces = "application/pdf;charset=UTF-8")
        public void updateReport(Model model, @PathVariable String report_name, HttpServletRequest request,
                HttpServletResponse response,HttpSession session) {
            try {
                User user = (User) session.getAttribute("user");
                //这是用户登录后保存到session里的用户信息（可以用别的对象来替代这个）
                if(user==null){
                    return ;
                }
    
                PdfReader reader1 =null;
                try {
                    // 调用刚刚写的生成PDF的方法，将这个字节数组获取。
                    byte[] pdfUserByte=ReportKit.createReport(user);
    
                    if(pdfUserByte==null||pdfUserByte.length==0){
                        return;
                    }
                    //用pdfReader来读取字节数组，这里将文档信息读入
                     reader1 = new PdfReader(pdfUserByte);
    
                } catch (Exception e) {
                    System.out.println(e.getMessage());
                    return ;
                }
    
                if(reader1==null) return;
                //第二个PDF的读取
                PdfReader reader2;
                // 报告的PDF
                reader2 = new PdfReader("C:\\Users\\Administrator\\Desktop\\report.pdf");
    
                Document document = new Document();
                PdfWriter writer = PdfWriter.getInstance(document, response.getOutputStream());
                document.open();
                PdfContentByte cb = writer.getDirectContent();
                int totalPages = 0;
                totalPages += reader1.getNumberOfPages();
                totalPages += reader2.getNumberOfPages();
    
                java.util.List<PdfReader> readers = new ArrayList<PdfReader>();
                readers.add(reader1);
                readers.add(reader2);
    
                int pageOfCurrentReaderPDF = 0;
                Iterator<PdfReader> iteratorPDFReader = readers.iterator();
    
                // Loop through the PDF files and add to the output.
                while (iteratorPDFReader.hasNext()) {
                    PdfReader pdfReader = iteratorPDFReader.next();
    
                    // Create a new page in the target for each source page.
                    while (pageOfCurrentReaderPDF < pdfReader.getNumberOfPages()) {
                        document.newPage();//创建新的一页
                        pageOfCurrentReaderPDF++;
                        PdfImportedPage page = writer.getImportedPage(pdfReader, pageOfCurrentReaderPDF);
                        cb.addTemplate(page, 0, 0);
                    }
                    pageOfCurrentReaderPDF = 0;
                }
                document.close();
                writer.close();
            } catch (IOException | DocumentException e) {
                e.printStackTrace();
            }
        }

关于如何在页面预览这个PDF，我用了object标签来获取。   
jsp上的部分片段

标签很好的实现了PDF预览的功能，如果是URL的PDF，data直接输入URL，就能将PDF在页面预览，感觉蛮好用的。

如果哪里有错误或者不足之处，欢迎大家指出，有什么问题可以一起交流一下。