222059-1734531659fea9

合并多个pdf为一个总的pdf，并生成书签

最近做了一个需求，需要将用户上传的多个pdf文件，合并成成一个pdf文件，生成书签。

采用了开源的pdfbox库，写了一个demo如下

1.引入pom依赖

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<!-- pdf box -->
<dependency>
    <groupId>org.apache.pdfbox</groupId>
    <artifactId>pdfbox</artifactId>
    <version>2.0.27</version>
</dependency>

<!-- 使用该依赖处理json -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.58</version>
</dependency>

2.定义service接口

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import com.alibaba.fastjson.JSONObject;

import java.io.IOException;

public interface PdfService {

    /**
     * 合并多个pdf文件到一个文件
     *
     * @param outputPath
     * @param filePath
     * @return
     */
    JSONObject mergeFile(String outputPath, String... filePath) throws IOException;

    /**
     * 给pdf文件添加书签
     * @param sourcePath
     * @param filePath
     * @throws IOException
     */
    void addBookMark(JSONObject json, String sourcePath, String... filePath) throws IOException;
}

3.编写实现类

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import com.alibaba.fastjson.JSONObject;
import com.xiaoyun.service.PdfService;
import org.apache.pdfbox.multipdf.PDFMergerUtility;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PageMode;
import org.apache.pdfbox.pdmodel.interactive.documentnavigation.destination.PDPageXYZDestination;
import org.apache.pdfbox.pdmodel.interactive.documentnavigation.outline.PDDocumentOutline;
import org.apache.pdfbox.pdmodel.interactive.documentnavigation.outline.PDOutlineItem;
import org.springframework.stereotype.Service;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;

@Service
public class PdfServiceImpl implements PdfService {
    @Override
    public JSONObject mergeFile(String outputPath, String... pdfPaths) throws IOException {
        // 封装json对象 承载数据
        JSONObject json = new JSONObject();
        // 记录文件页数
        HashMap<String, Integer> pageMap = new HashMap<>();

        // 合并文件逻辑
        PDFMergerUtility merger = new PDFMergerUtility();
        merger.setDestinationFileName(outputPath);

        for (String pdf : pdfPaths) {
            File file = new File(pdf);
            merger.addSource(file);

            try (PDDocument doc = PDDocument.load(file)) {
                pageMap.put(pdf, doc.getNumberOfPages());
            }
        }
        merger.mergeDocuments(null);

        json.put("page", pageMap);
        return json;
    }

    @Override
    public void addBookMark(JSONObject json, String sourcePath, String... filePath) throws IOException {
        JSONObject page = json.getJSONObject("page");
        // 当前页面
        int curPage = 0;

        // 添加书签
        try (
            // 源文件
            PDDocument document = PDDocument.load(new File(sourcePath))
        ) {
            // 创建大纲
            PDDocumentOutline documentOutline = new PDDocumentOutline();
            document.getDocumentCatalog().setDocumentOutline(documentOutline);

            // 创建大纲项目
            PDOutlineItem pagesOutline = new PDOutlineItem();
            pagesOutline.setTitle("大  纲");
            documentOutline.addLast(pagesOutline);

            for (String path : filePath) {
                PDPageXYZDestination pdPageXYZDestination = new PDPageXYZDestination();
                pdPageXYZDestination.setTop(5000);
                pdPageXYZDestination.setLeft(0);
                pdPageXYZDestination.setPage(document.getPage(curPage));

                PDOutlineItem bookmark = new PDOutlineItem();
                bookmark.setDestination(pdPageXYZDestination);
                bookmark.setTitle(path.split("\\.")[0].replace("D:\\素材\\", ""));
                pagesOutline.addLast(bookmark);

                curPage += page.getInteger(path);
            }

            pagesOutline.openNode();
            documentOutline.openNode();

            document.getDocumentCatalog().setPageMode(PageMode.USE_OUTLINES);

            document.save(sourcePath);
        }

    }
}

4.测试

在单元测试中写入如下代码

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@Test
void contextLoads() {
    try {
        JSONObject json = pdfService.mergeFile("D:\\素材\\result.pdf", "D:\\素材\\林俊杰.pdf", "D:\\素材\\周杰伦.pdf", "D:\\素材\\黄霄雲.pdf");
        pdfService.addBookMark(json,"D:\\素材\\result.pdf", "D:\\素材\\林俊杰.pdf", "D:\\素材\\周杰伦.pdf", "D:\\素材\\黄霄雲.pdf");
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
}

打开新生成的文件，内容如下：

image-20241221125920711