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Java中多个pdf合并为一个pdf文件工具类

发布时间 2023-05-29 19:41:06作者: Tiory

Java中多个pdf合并为一个pdf文件工具类

方案一：

  1. 引入依赖
<dependency>
    <groupId>com.lowagie</groupId>
    <artifactId>itext</artifactId>
    <version>2.1.7</version>
</dependency>
  1. 工具类
import com.lowagie.text.Document;
import com.lowagie.text.pdf.PdfCopy;
import com.lowagie.text.pdf.PdfImportedPage;
import com.lowagie.text.pdf.PdfReader;

import java.nio.file.Files;
import java.nio.file.Paths;

public class PdfUtils {
    /**
     * 合并pdf
     *
     * @param files   需要合并的pdf路径  String[] files = {"D:/ruoyi/uploadPath/pdf/2023/5/a.pdf", "D:/ruoyi/uploadPath/pdf/2023/5/b.pdf"};
     * @param newfile 合并成新的文件的路径  String savepath = "D:/ruoyi/Dict/back.pdf";
     */
    public static boolean mergePdfFiles(String[] files, String newfile) {
        boolean retValue = false;
        Document document = null;
        PdfCopy copy = null;
        PdfReader reader = null;
        try {
            document = new Document(new PdfReader(files[0]).getPageSize(1));
            copy = new PdfCopy(document, Files.newOutputStream(Paths.get(newfile)));
            document.open();
            for (String file : files) {
                reader = new PdfReader(file);
                int n = reader.getNumberOfPages();
                for (int j = 1; j <= n; j++) {
                    document.newPage();
                    PdfImportedPage page = copy.getImportedPage(reader, j);
                    copy.addPage(page);
                }
                reader.close();
            }
            retValue = true;
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (reader != null) {
                reader.close();
            }
            if (copy != null) {
                copy.close();
            }
            if (document != null) {
                document.close();
            }
        }
        return retValue;
    }
//    psvm 中调用
//        boolean b = mergePdfFiles(files, savepath);
//        System.out.println(b);
}

方案二：

  1. 引入依赖
<dependency>
    <groupId>org.apache.pdfbox</groupId>
    <artifactId>pdfbox</artifactId>
    <version>2.0.25</version>
</dependency>
  1. 工具类
  // pdf合并工具类
    public static File mulFile2One(List<File> files, String targetPath) throws Exception {
        PDFMergerUtility mergePdf = new PDFMergerUtility();
        for (File f : files) {
            if(f.exists() && f.isFile()){
                // 循环添加要合并的pdf
                mergePdf.addSource(f);
            }
        }
        // 设置合并生成pdf文件名称
        mergePdf.setDestinationFileName(targetPath);
        // 合并pdf
        mergePdf.mergeDocuments(MemoryUsageSetting.setupMainMemoryOnly());
        return new File(targetPath);
    }
    
 public static void main(String[] args) {

        List<File> files = new ArrayList();
        File file = new File("D:/ruoyi/uploadPath/pdf/2023/5");
        File[] tempList = file.listFiles();
        //获取该文件夹下的文件（文件都是PDF）
        for (int i = 0; i < tempList.length; i++) {
            if (tempList[i].isFile()) {
                files.add(tempList[i]);
            }
        }
        try {
            File f = mulFile2One(files, "D:/ruoyi/Dict/合成PDF.pdf");
            System.out.println(f.length());
        } catch (Exception e){
            e.printStackTrace();
        }
    }

方案区别

方案一合成的比方案二的小50kb左右