Java Word转PDF(直接转和以图片形式转）、PDF转图片、图片转PDF

在淘宝上找了一家写代码的店铺写了一个工具类，再参考网上的代码，改了改
用到的类库：

        <!-- https://mvnrepository.com/artifact/org.apache.pdfbox/fontbox -->
        <!--word转pdf-->
        <dependency>
            <groupId>com.documents4j</groupId>
            <artifactId>documents4j-local</artifactId>
            <version>1.1.12</version>
        </dependency>

        <dependency>
            <groupId>com.documents4j</groupId>
            <artifactId>documents4j-transformer-msoffice-word</artifactId>
            <version>1.1.12</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.apache.pdfbox/pdfbox -->
        <!-- pdf转图片和图片转pdf-->
        <dependency>
            <groupId>org.apache.pdfbox</groupId>
            <artifactId>pdfbox</artifactId>
            <version>2.0.29</version>
        </dependency>

工具类代码：

import com.documents4j.api.DocumentType;
import com.documents4j.job.LocalConverter;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDPageContentStream;
import org.apache.pdfbox.pdmodel.common.PDRectangle;
import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
import org.apache.pdfbox.rendering.PDFRenderer;

import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.stream.ImageInputStream;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class FileConvertor {

    /**
     * 根据word每页生成图片，再根据得到的图片，合并生成PDF
     */
    public static void wordToImagePDF(String wordPath,String imageDirectory, String targetPDF) throws IOException {
        //生成临时pdf文件
        File tempFile = File.createTempFile("temp", ".pdf");
        String temporaryPDF = tempFile.getAbsolutePath();
        //将word转换为pdf，并写入临时pdf
        wordToPDF(wordPath, temporaryPDF);
        //将临时pdf转换为图片
        List<String> images = pdfToImages(temporaryPDF,imageDirectory,300,"png");
        //将转换出来的图片合并为pdf
        try (PDDocument pdDocument = new PDDocument()) {
            for (String imagePath : images) {
                imageToPDF(imagePath, pdDocument);
            }
            pdDocument.save(targetPDF);
        }
        //删除临时pdf
        Files.delete(Paths.get(temporaryPDF));
    }

    /**
     * Word文档转换为PDF文档
     * @param wordPath Word文档路径
     * @param pdfPath  生成的PDF路径
     */
    public static void wordToPDF(String wordPath, String pdfPath) throws IOException {
        File inputWord = new File(wordPath);
        File outputFile = new File(pdfPath);
        InputStream docxInputStream = Files.newInputStream(inputWord.toPath());
        OutputStream outputStream = Files.newOutputStream(outputFile.toPath());
        LocalConverter.builder().build().convert(docxInputStream)
                .as(DocumentType.DOCX)
                .to(outputStream)
                .as(DocumentType.PDF).execute();
        outputStream.close();
        docxInputStream.close();
    }

    /**
     * PDF文件转图片（word一页对应一个图像）
     * 图片将保存文件夹下，根据页数命名
     * @param pdfPath PDF文件路径
     * @param imageDirectory 生成的图片保存的文件夹
     * @param dpi 生成图片dpi
     * @param formatName 生成图片的格式
     */
    public static List<String> pdfToImages(String pdfPath,String imageDirectory,
                                           float dpi, String formatName) throws IOException {
        File file = new File(pdfPath);
        ArrayList<String> list = new ArrayList<>();
        try (PDDocument doc = PDDocument.load(file)) {
            PDFRenderer renderer = new PDFRenderer(doc);
            int pageCount = doc.getNumberOfPages();
            for (int i = 0; i < pageCount; i++) {
                BufferedImage image = renderer.renderImageWithDPI(i, dpi);
                int pageIndex = i + 1;
                String imagePath = imageDirectory +File.separator + pageIndex + "."+formatName;
                ImageIO.write(image, formatName, new File(imagePath));
                list.add(imagePath);
            }
        }
        return list;
    }


    /**
     * 图片转PDF
     */
    public static void imageToPDF(String imagePath, PDDocument document) throws IOException {
        //获取图片长宽
        File file = new File(imagePath);
        String fileSuffix = imagePath.substring(imagePath.lastIndexOf(".") + 1);
        Iterator<ImageReader> readers = ImageIO.getImageReadersByFormatName(fileSuffix);
        ImageReader reader = readers.next();
        ImageInputStream input = ImageIO.createImageInputStream(Files.newInputStream(file.toPath()));
        reader.setInput(input, true);
        int width = reader.getWidth(0);
        int height = reader.getHeight(0);
        //根据图片大小动态生成pdf页面
        PDPage pdPage = new PDPage(new PDRectangle(width, height));
        document.addPage(pdPage);
        PDImageXObject pdImageXObject = PDImageXObject.createFromFile(imagePath, document);
        PDPageContentStream contentStream = new PDPageContentStream(document, pdPage);
        //写入图片
        contentStream.drawImage(pdImageXObject, 0, 0);
        contentStream.close();
        input.close();
    }
}