最新版访问：https://blog.csdn.net/wmf_helloWorld/article/details/107105353
1、根据文件路径获取文件，并将PDF文件的每一页转换为一个图片。其中要将图片转为base64格式的。

/**
     * <p>Description PDF文件转成图片</p>
     * @author wumf
     * @date 2020年1月20日 上午11:00:47
     * @param PdfFilePath PDF文件路径
     * @param fileImageList 存放图片文件
     * @param dpi 越大越清晰，转换也越慢
     * @return 文件页数
     * @throws CodeException 
     */
    public int pdfTurnImage(String pdfFilePath, List<String> fileImageList, int dpi) throws CodeException {
        
        File file = new File(pdfFilePath);
        PDDocument pdDocument;
        int pages = 0;
        try {
            
            pdDocument = PDDocument.load(file);
            PDFRenderer renderer = new PDFRenderer(pdDocument);
            PdfReader reader = new PdfReader(pdfFilePath);
            pages = reader.getNumberOfPages();
            LOGGER.info(LogType.INFO, "PDF文件一共有"+pages+"页");
            for (int i = 0; i < pages; i++) {
                BufferedImage image = renderer.renderImageWithDPI(i, dpi);                           
                fileImageList.add(base64Image(image));
            }
            
        } catch (Exception e) {
            LOGGER.error(LogType.ERROR, e);
            throw new CodeException(XYRFileServerConstants.ERROR_CODE_2017, XYRFileServerConstants.ERROR_MESSAGE_2017, e);
        }
        
        return pages;
    }

2、base64Image，其中的Base64.encode(bytes)方法为自定义的方法，可以去网上百度其他方式

/**
     * <p>Description image转成base64</p>
     * @author wumf
     * @date 2020年1月20日 上午11:26:24
     * @param image
     * @return
     * @throws CodeException
     */
    private String base64Image(BufferedImage image) throws CodeException {
        try(ByteArrayOutputStream baos = new ByteArrayOutputStream()) {            
            ImageIO.write(image, "png", baos);//写入流中
            byte[] bytes = baos.toByteArray();//转换成字节
            return new String(Base64.encode(bytes),"UTF-8");
        } catch (Exception e) {
            LOGGER.error(LogType.ERROR, e);
            throw new CodeException(XYRFileServerConstants.ERROR_CODE_2017, XYRFileServerConstants.ERROR_MESSAGE_2017, e);
        }        

    }

3、此时文件图片已经在集合中，可以解析查看

List<String> list = response.getFileImageList();
        for (int i = 0; i < list.size(); i++) {
            File file = new File("/20200120\\image"+i+".jpg");
            String image = list.get(i);
            try (FileOutputStream fos = new FileOutputStream(file)){
                fos.write(Base64.decode(image));                
            } catch (Exception e) {
                throw new CodeException(XYRFileServerConstants.ERROR_CODE_2018, XYRFileServerConstants.ERROR_MESSAGE_2018);
            }
        }

4、需要引用的包

import javax.imageio.ImageIO;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.rendering.PDFRenderer;
import org.springframework.stereotype.Component;

import com.itextpdf.text.pdf.PdfReader;

import cfca.sadk.util.Base64;

5、maven依赖

<!-- PDF -->  
        <dependency> 
            <groupId>com.itextpdf</groupId>  
            <artifactId>itext-asian</artifactId> 
        </dependency>  
        <dependency> 
            <groupId>cpcn.common.3rd</groupId>  
            <artifactId>itext-xtra</artifactId> 
        </dependency>  
        <dependency> 
            <groupId>com.itextpdf</groupId>  
            <artifactId>itextpdf</artifactId> 
        </dependency>
        <dependency>
    		<groupId>org.apache.pdfbox</groupId>
    		<artifactId>pdfbox</artifactId>
    		<version>2.0.9</version>
		</dependency>

5、测试demo

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.UUID;
import javax.imageio.ImageIO;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.rendering.PDFRenderer;
import com.itextpdf.text.pdf.PdfReader;

public class LocalTest {

    // 获取到 pdf 文件路径

    // 获取到图片存放路径

    // study-1.jpg

    public static void main(String[] args) {
        pdf2Image("D:\\xyrFileRepository\\PolicyDeclare\\20200120\\202001200944427972857793199.pdf", "D:/temp/picture", 150);

    }

    /***
     * 
     * PDF文件转PNG图片，全部页数
     * @param PdfFilePath  pdf完整路径
     * @param imgFilePath 图片存放的文件夹
     * @param dpi dpi越大转换后越清晰，相对转换速度越慢
     * @return list 获取到pdf 的文件路径 /dsd/d.pdf 然后拼上绝对路径
     * 
     */

    public static Integer pdf2Image(String PdfFilePath, String dstImgFolder, int dpi) {

        UUID uuid = UUID.randomUUID();
        String uuId = uuid.toString();
        System.out.println(uuId);
        File file = new File(PdfFilePath);
        @SuppressWarnings("resource")
        PDDocument pdDocument = new PDDocument();
        try {
            // String imagePDFName = file.getName().substring(0, dot); //
            // 获取图片文件名
            String imgFolderPath = null;
            if (dstImgFolder.equals("")) {
                imgFolderPath = dstImgFolder + File.separator + uuId;// 获取图片存放的文件夹路径
            } else {
                imgFolderPath = dstImgFolder + File.separator + uuId;
            }
            if (createDirectory(imgFolderPath)) {
                pdDocument = PDDocument.load(file);
                PDFRenderer renderer = new PDFRenderer(pdDocument);
                /* dpi越大转换后越清晰，相对转换速度越慢 */
                PdfReader reader = new PdfReader(PdfFilePath);
                int pages = reader.getNumberOfPages();
                System.out.println("pdf总共多少页-----" + pages);
                StringBuffer imgFilePath = null;
                for (int i = 0; i < pages; i++) {
                    String imgFilePathPrefix = imgFolderPath + File.separator + "study";
                    System.out.println("imgFilePathPrefix=====" + imgFilePathPrefix);
                    imgFilePath = new StringBuffer();
                    imgFilePath.append(imgFilePathPrefix);
                    imgFilePath.append("-");
                    imgFilePath.append(String.valueOf(i));
                    imgFilePath.append(".jpg");
                    File dstFile = new File(imgFilePath.toString());
                    BufferedImage image = renderer.renderImageWithDPI(i, dpi);
                    System.out.println(dstFile);
                    ImageIO.write(image, "png", dstFile);
                }
                System.out.println("PDF文档转PNG图片成功！");
                System.out.println("做保存操作保存数据库-----");
                return 1;
            } else {
                System.out.println("PDF文档转PNG图片失败：" + "创建" + imgFolderPath + "失败");
                return -1;
            }
        } catch (IOException e) {
            e.printStackTrace();
            return -1;
        }
    }

    private static boolean createDirectory(String folder) {
        File dir = new File(folder);
        if (dir.exists()) {
            return true;
        } else {
            return dir.mkdirs();
        }
    }

    // 删除文件夹
    // param folderPath 文件夹完整绝对路径
    public static void delFolder(String folderPath) {
        try {
            delAllFile(folderPath); // 删除完里面所有内容
            String filePath = folderPath;
            filePath = filePath.toString();
            java.io.File myFilePath = new java.io.File(filePath);
            myFilePath.delete(); // 删除空文件夹
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    // 删除指定文件夹下所有文件
    // param path 文件夹完整绝对路径
    public static boolean delAllFile(String path) {
        boolean flag = false;
        File file = new File(path);
        if (!file.exists()) {
            return flag;
        }
        if (!file.isDirectory()) {
            return flag;
        }
        String[] tempList = file.list();
        File temp = null;
        for (int i = 0; i < tempList.length; i++) {
            if (path.endsWith(File.separator)) {
                temp = new File(path + tempList[i]);
            } else {
                temp = new File(path + File.separator + tempList[i]);
            }
            if (temp.isFile()) {
                temp.delete();
            }
            if (temp.isDirectory()) {
                delAllFile(path + "/" + tempList[i]);// 先删除文件夹里面的文件
                delFolder(path + "/" + tempList[i]);// 再删除空文件夹
                flag = true;
            }
        }
        return flag;
    }
}