pdf转图片，提取文字，提取图片

1、使用pdfbox

        <dependency>
            <groupId>org.apache.pdfbox</groupId>
            <artifactId>pdfbox</artifactId>
            <version>2.0.21</version>
        </dependency>

2、code

import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDResources;
import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
import org.apache.pdfbox.rendering.PDFRenderer;
import org.apache.pdfbox.text.PDFTextStripper;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

/**
 * @Author: xu.dm
 * @Date: 2020/10/27 17:06
 * @Version: 1.0
 * @Description: pdf转图片，提取文字，提取图片
 **/
public class PdfUtil {
    /**
     * 转换全部的pdf
     *
     * @param filename PDF文件全路径
     * @param type     图片类型
     */
    public static void pdf2png(String filename, String type) {
        // 将pdf装图片 并且自定义图片得格式大小
        File file = new File(filename);
        String parentPath = file.getParent();
        String name = file.getName();
        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, 144); // Windows native DPI
                ImageIO.write(image, type, new File(parentPath + "/" + name + "_" + (i + 1) + "." + type));
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    /**
     * 自由确定起始页和终止页
     *
     * @param filename     PDF文件全路径
     * @param indexOfStart 开始页  开始转换的页码，从0开始
     * @param indexOfEnd   结束页  停止转换的页码，-1为全部
     * @param type         图片类型
     */
    public static void pdf2png(String filename, int indexOfStart, int indexOfEnd, String type) {
        // 将pdf装图片 并且自定义图片得格式大小
        File file = new File(filename);
        String parentPath = file.getParent();
        String name = file.getName();

        try {
            PDDocument doc = PDDocument.load(file);
            PDFRenderer renderer = new PDFRenderer(doc);
            int pageCount = doc.getNumberOfPages();
            for (int i = indexOfStart; i < indexOfEnd; i++) {
                BufferedImage image = renderer.renderImageWithDPI(i, 144); // Windows native DPI
                ImageIO.write(image, type, new File(parentPath + "\\" + name + "_" + (i + 1) + "." + type));
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 提取pdf中的文字，例如：用word转存pdf，那么里面文字就可以提取，如果是图片转存pdf不能提取
     * @param filename pdf全路径
     */
    public static String extractText(String filename) {
        File file = new File(filename);
        try {
            PDDocument doc = PDDocument.load(file);
            int pages = doc.getNumberOfPages();
            // 读文本内容
            PDFTextStripper stripper = new PDFTextStripper();
            // 设置按顺序输出
            stripper.setSortByPosition(true);
            stripper.setStartPage(1);
            stripper.setEndPage(pages);
            return stripper.getText(doc);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 从PDF中提取图片
     * @param filename pdf全路径
     * @param type 图片类型，后缀
     */
    public static void extractImage(String filename, String type) {
        File file = new File(filename);
        String parentPath = file.getParent();
        String name = file.getName();
        try {
            PDDocument doc = PDDocument.load(file);
            int pages = doc.getNumberOfPages();
            int j = 0;
            for (int i = 0; i < pages; i++) {
                PDPage page = doc.getPage(i);
                PDResources resources = page.getResources();
                Iterable<COSName> xObjectNames = resources.getXObjectNames();
                if (xObjectNames == null) continue;
                for (COSName cosName : xObjectNames) {
                    if (resources.isImageXObject(cosName)) {
                        PDImageXObject image = (PDImageXObject) resources.getXObject(cosName);
                        BufferedImage bufferedImage = image.getImage();
                        ImageIO.write(bufferedImage, type, new File(parentPath + "\\" + name + "_" + (++j) + "." + type));
                    }
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}