java操作PDF：转换、合成、切分

将PDF每一页切割成图片

PDFUtils.cutPNG("D:/tmp/1.pdf","D:/tmp/输出图片路径/");

将PDF转换成一张长图片

PDFUtils.transition_ONE_PNG("D:/tmp/1.pdf");

将多张图片合并成一个PDF文件

PDFUtils.merge_PNG("D:/tmp/测试图片/");

将多个PDF合并成一个PDF文件

PDFUtils.merge_PDF("D:/tmp/测试图片/");

取出指定PDF的起始和结束页码作为新的pdf

PDFUtils.getPartPDF("D:/tmp/1.pdf",3,5);

引入依赖

                    org.apache.pdfbox            pdfbox            2.0.24                            com.itextpdf            itextpdf            5.5.13.2        

代码（如下4个java类放在一起直接使用即可）

PDFUtils.java

import com.itextpdf.text.Document;import com.itextpdf.text.DocumentException;import com.itextpdf.text.Image;import com.itextpdf.text.pdf.*;import org.apache.pdfbox.io.MemoryUsageSetting;import org.apache.pdfbox.multipdf.PDFMergerUtility;import org.apache.pdfbox.multipdf.Splitter;import org.apache.pdfbox.pdmodel.PDDocument;import org.apache.pdfbox.pdmodel.PDPage;import org.apache.pdfbox.pdmodel.PDResources;import org.apache.pdfbox.pdmodel.common.PDRectangle;import org.apache.pdfbox.rendering.ImageType;import org.apache.pdfbox.rendering.PDFRenderer;import javax.imageio.ImageIO;import java.awt.image.BufferedImage;import java.io.File;import java.io.FileOutputStream;import java.io.FilenameFilter;import java.io.IOException;import java.util.ArrayList;import java.util.List;public class PDFUtils {        public static void cutPNG(String pdfPath) throws IOException {        File pdf = new File(pdfPath);        cutPNG(pdfPath, pdf.getParent() + File.separator + pdf.getName() + "_pngs");    }        public static void cutPNG(String pdfPath, String outPath) throws IOException {        File outDir = new File(outPath);        if (!outDir.exists()) outDir.mkdirs();        cutPNG(new File(pdfPath), outDir);    }        public static void cutPNG(File pdf, File outDir) throws IOException {        LogUtils.info("PDF分解图片工作开始");        List list = getImgList(pdf);        LogUtils.info(pdf.getName() + " 一共发现了 " + list.size() + " 页");        FileUtils.cleanDir(outDir);        for (int i = 0; i < list.size(); i++) {            IMGUtils.saveImageToFile(list.get(i), outDir.getAbsolutePath() + File.separator + (i + 1) + ".png");            LogUtils.info("已保存图片：" + (i + 1) + ".png");        }        LogUtils.info("PDF分解图片工作结束，一共分解出" + list.size() + "个图片文件，保存至：" + outDir.getAbsolutePath());    }        public static void transition_ONE_PNG(String pdfPath) throws IOException {        transition_ONE_PNG(new File(pdfPath));    }        public static void transition_ONE_PNG(File pdf) throws IOException {        LogUtils.info("PDF转换长图工作开始");        List list = getImgList(pdf);        LogUtils.info(pdf.getName() + " 一共发现了 " + list.size() + " 页");        BufferedImage image = list.get(0);        for (int i = 1; i < list.size(); i++) {            image = IMGUtils.verticalJoinTwoImage(image, list.get(i));        }        byte[] data = IMGUtils.getBytes(image);        String imgPath = pdf.getParent() + File.separator + pdf.getName().replaceAll("\\.", "_") + ".png";        FileUtils.saveDataToFile(imgPath, data);        LogUtils.info("PDF转换长图工作结束，合成尺寸：" + image.getWidth() + "x" + image.getHeight() + "，合成文件大小：" + data.length / 1024 + "KB，保存至：" + imgPath);    }        private static List getImgList(File pdf) throws IOException {        PDDocument pdfDoc = PDDocument.load(pdf);        List imgList = new ArrayList<>();        PDFRenderer pdfRenderer = new PDFRenderer(pdfDoc);        int numPages = pdfDoc.getNumberOfPages();        for (int i = 0; i < numPages; i++) {            BufferedImage image = pdfRenderer.renderImageWithDPI(i, 300, ImageType.RGB);            imgList.add(image);        }        pdfDoc.close();        return imgList;    }        public static void merge_PNG(String pngsDirPath) throws Exception {        File pngsDir = new File(pngsDirPath);        merge_PNG(pngsDir, pngsDir.getName() + ".pdf");    }        private static void merge_PNG(File pngsDir, String pdfName) throws Exception {        File pdf = new File(pngsDir.getParent() + File.separator + pdfName);        if (!pdf.exists()) pdf.createNewFile();        File[] pngList = pngsDir.listFiles((dir, name) -> name.toLowerCase().endsWith(".png"));        LogUtils.info("在" + pngsDir.getAbsolutePath() + "，一共发现" + pngList.length + "个PNG文件");        Document document = new Document();        FileOutputStream fo = new FileOutputStream(pdf);        PdfWriter writer = PdfWriter.getInstance(document, fo);        document.open();        for (File f : pngList) {            document.newPage();            byte[] bytes = FileUtils.getFileBytes(f);            Image image = Image.getInstance(bytes);            float heigth = image.getHeight();            float width = image.getWidth();            int percent = getPercent2(heigth, width);            image.setAlignment(Image.MIDDLE);            image.scalePercent(percent + 3);// 表示是原来图像的比例;            document.add(image);            System.out.println("正在合成" + f.getName());        }        document.close();        writer.close();        System.out.println("PDF文件生成地址：" + pdf.getAbsolutePath());    }    private static int getPercent2(float h, float w) {        int p = 0;        float p2 = 0.0f;        p2 = 530 / w * 100;        p = Math.round(p2);        return p;    }        public static void merge_PDF(String pngsDirPath) throws IOException {        File pngsDir = new File(pngsDirPath);        merge_PDF(pngsDir, pngsDir.getName() + "_合并.pdf");    }        private static void merge_PDF(File pngsDir, String pdfName) throws IOException {        File[] pdfList = pngsDir.listFiles((dir, name) -> name.toLowerCase().endsWith(".pdf"));        LogUtils.info("在" + pngsDir.getAbsolutePath() + "，一共发现" + pdfList.length + "个PDF文件");        PDFMergerUtility pdfMergerUtility = new PDFMergerUtility();        pdfMergerUtility.setDestinationFileName(pngsDir.getParent() + File.separator + pdfName);        for (File f : pdfList) {            pdfMergerUtility.addSource(f);        }        pdfMergerUtility.mergeDocuments(MemoryUsageSetting.setupMainMemoryOnly());    }    public static void getPartPDF(String pdfPath, int from, int end) throws Exception {        pdfPath = pdfPath.trim();        Document document = null;        PdfCopy copy = null;        PdfReader reader = new PdfReader(pdfPath);        int n = reader.getNumberOfPages();        if (end == 0) {            end = n;        }        document = new Document(reader.getPageSize(1));        copy = new PdfCopy(document, new FileOutputStream(pdfPath.substring(0, pdfPath.length() - 4) + "_" + from + "_" + end + ".pdf"));        document.open();        for (int j = from; j <= end; j++) {            document.newPage();            PdfImportedPage page = copy.getImportedPage(reader, j);            copy.addPage(page);        }        document.close();    }}

IMGUtils.java

import javax.imageio.ImageIO;import java.awt.*;import java.awt.image.BufferedImage;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.FileInputStream;import java.io.IOException;public class IMGUtils {        public static byte[] getBytes(BufferedImage image){        return getBytes(image,"png");    }        public static byte[] getBytes(BufferedImage image,String fileType){        ByteArrayOutputStream outStream = new ByteArrayOutputStream();        try {            ImageIO.write(image,fileType,outStream);        } catch (IOException e) {            e.printStackTrace();        }        return outStream.toByteArray();    }        public static BufferedImage getImage(String filePath){        try {            return ImageIO.read(new FileInputStream(filePath));        } catch (IOException e) {            e.printStackTrace();        }        return null;    }        public static BufferedImage getImage(byte[] data){        try {            return ImageIO.read(new ByteArrayInputStream(data));        } catch (IOException e) {            e.printStackTrace();        }        return null;    }        public static void saveImageToFile(BufferedImage image,String filePath) throws IOException {        FileUtils.saveDataToFile(filePath,getBytes(image));    }        public static BufferedImage verticalJoinTwoImage(BufferedImage image1, BufferedImage image2){        if(image1==null)return image2;        if(image2==null)return image1;        BufferedImage image=new BufferedImage(image1.getWidth(),image1.getHeight()+image2.getHeight(),image1.getType());        Graphics2D g2d = image.createGraphics();        g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);        g2d.drawImage(image1, 0, 0, image1.getWidth(), image1.getHeight(), null);        g2d.drawImage(image2, 0, image1.getHeight(), image2.getWidth(), image2.getHeight(), null);        g2d.dispose();// 释放图形上下文使用的系统资源        return image;    }        public static BufferedImage cutImage(BufferedImage image,int x,int y,int width,int height){        if(image==null)return null;        return image.getSubimage(x,y,width,height);    }}

FileUtils.java

import java.io.*;public class FileUtils {        public static void saveDataToFile(String filePath,byte[] data) throws IOException {        File file = new File(filePath);        if(!file.exists())file.createNewFile() ;        FileOutputStream outStream = new FileOutputStream(file);        outStream.write(data);        outStream.flush();        outStream.close();    }        public static byte[] getFileBytes(File file) throws IOException {        if(!file.exists()||(file.exists()&&!file.isFile()))return null;        InputStream inStream=new FileInputStream(file);        ByteArrayOutputStream outStream = new ByteArrayOutputStream();        byte[] buffer = new byte[1024];        int len;        while ((len = inStream.read(buffer)) != -1) {            outStream.write(buffer, 0, len);        }        inStream.close();        return outStream.toByteArray();    }        public static String getFileText(String path){        try {            byte[] data= getFileBytes(new File(path));            return new String(data);        } catch (Exception e) {            return "";        }    }        public static void cleanDir(File dir){        if(dir!=null&&dir.isDirectory()){            for(File file:dir.listFiles()){                if(file.isFile())file.delete();                if(file.isDirectory())cleanDir(file);            }        }    }}

LogUtils.java

public class LogUtils {    public static void info(String context){        System.out.println(context);    }    public static void warn(String context){        System.out.println(context);    }    public static void error(String context){        System.out.println(context);    }}

来源地址：https://blog.csdn.net/qq_43319748/article/details/132133397