Java项目中整合多个pdf合并为一个pdf

news2024/12/28 8:50:54

一、Java项目中整合多个pdf合并为一个pdf

gitee笔记路径：https://gitee.com/happy_sad/drools

一、依赖导入

<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itextpdf</artifactId>
    <version>5.5.6</version>
</dependency>
<dependency>
    <groupId>org.kie</groupId>
    <artifactId>kie-api</artifactId>
    <version>7.6.0.Final</version>
</dependency>
<dependency>
    <groupId>org.kie</groupId>
    <artifactId>kie-internal</artifactId>
    <version>7.6.0.Final</version>
</dependency>

二、设置端口

server.port=8082

三、设置已存在的多个pdf

注意：此次为模拟获取多个pdf，所以本人做两个pdf的合并实验，所以将两个pdf放入项目中的/resources/mergepdfs文件夹中，合并时遍历该文件夹下的所有文件，转换字节流

四、controller

package com.jin.test.controller;

import com.itextpdf.text.Document;
import com.itextpdf.text.pdf.PdfCopy;
import com.itextpdf.text.pdf.PdfImportedPage;
import com.itextpdf.text.pdf.PdfReader;
import lombok.extern.log4j.Log4j2;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;


import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.stream.Stream;

/**
 * @Package:com.jin.test.controller
 * @ClassName: MergepdfTestController
 * @Description: 项目中整合多个pdf合并为一个pdf
 * @Date: 2024/07/21 14:22
 * @Author: Jin
 */
@Log4j2
@RestController
@RequestMapping("/mergepdf")
public class MergepdfTestController {

    @Autowired
    private ResourceLoader resourceLoader;

    @RequestMapping("/download")
    public void downloadFile(HttpServletResponse response) throws Exception {
        List<byte[]> finalList = Collections.synchronizedList(new ArrayList<>());

        ArrayList<String> fileNames = new ArrayList<>();
        Resource folderResource = resourceLoader.getResource("classpath:" + "mergepdfs");
        if (folderResource.exists()) {
            try (Stream<Path> files = Files.list(Paths.get(folderResource.getURI()))) {
                files.forEach(filePath ->
                        fileNames.add(filePath.toString())
                );
            }
            for (String fileNmae : fileNames) {
                File file = new File(fileNmae);
                FileInputStream fis = new FileInputStream(file);
                ByteArrayOutputStream bos = new ByteArrayOutputStream();
                int byteContent;
                while ((byteContent = fis.read()) != -1) {
                    bos.write(byteContent);
                }
                byte[] bytes = bos.toByteArray();
                finalList.add(bytes);
            }

            byte[] finalByte = this.mergepdf(finalList);
            ServletOutputStream outputStream = response.getOutputStream();
            outputStream.write(finalByte);
            outputStream.flush();
        } else {
            System.out.println("Folder not found: " + "mergepdfs");
        }
    }

    /**
     * pdf合并方法
     * @param bytes
     * @return
     * @throws Exception
     */
    public byte[] mergepdf(List<byte[]> bytes) throws Exception {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        Document document = new Document();
        PdfCopy copy = new PdfCopy(document, bos);
        document.open();
        for (byte[] bs : bytes) {
            PdfReader reader = new PdfReader(bs);
            int pageTotal = reader.getNumberOfPages();
            log.info("pdf的页码数是 ==>{}", pageTotal);
            for (int pageNo = 1; pageNo <= pageTotal; pageNo++) {
                document.newPage();
                PdfImportedPage page = copy.getImportedPage(reader, pageNo);
                copy.addPage(page);
            }
            reader.close();
        }
        document.close();
        byte[] pdfs = bos.toByteArray();
        bos.close();
        copy.close();
        return pdfs;
    }
}