见标题

以下是使用pdfbox提取pdf的文字，现在想提取pdf里面的印章，有朋友在线帮忙么

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDDocumentCatalog;
import org.apache.pdfbox.text.PDFTextStripper;
import java.io.File;
import java.io.IOException;

public class Test {
    public static void main(String[] args) {
        File pdfFile = new File("D:\\test.pdf");
        PDDocument document = null;
        try {
            document = PDDocument.load(pdfFile);

            // 获取页码
            int pages = document.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);

            PDDocumentCatalog cata = document.getDocumentCatalog();

            String content = stripper.getText(document);

            System.out.println(content);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

提取图片见代码：一般的图片可以提取，唯独pdf中是印章的时候提取不了

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDDocumentCatalog;
import org.apache.pdfbox.pdmodel.PDDocumentInformation;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDResources;
import org.apache.pdfbox.pdmodel.graphics.xobject.PDXObjectImage;
import org.apache.pdfbox.util.PDFTextStripper;

/**
 * 使用 pdfbox 解析pdf 文档信息
 *
 * @author diaodiaofly
 */
public class PDFParse {

    public static final String DATE_FORMAT = "yyyy-MM-dd HH:mm:ss";

    /**
     * 解析pdf文档信息
     *
     * @param pdfPath pdf文档路径
     * @throws Exception
     */
    public static void pdfParse(String pdfPath, String imgSavePath) throws Exception {
        InputStream input = null;
        File pdfFile = new File(pdfPath);
        PDDocument document = null;
        try {
            input = new FileInputStream(pdfFile);
            //加载 pdf 文档
            document = PDDocument.load(input);

            /** 文档属性信息 **/
            PDDocumentInformation info = document.getDocumentInformation();
            System.out.println("标题:" + info.getTitle());
            System.out.println("主题:" + info.getSubject());
            System.out.println("作者:" + info.getAuthor());
            System.out.println("关键字:" + info.getKeywords());

            System.out.println("应用程序:" + info.getCreator());
            System.out.println("pdf 制作程序:" + info.getProducer());

            System.out.println("作者:" + info.getTrapped());

            System.out.println("创建时间:" + dateFormat(info.getCreationDate()));
            System.out.println("修改时间:" + dateFormat(info.getModificationDate()));


            //获取内容信息
            PDFTextStripper pts = new PDFTextStripper();
            String content = pts.getText(document);
            System.out.println("内容:" + content);


            /** 文档页面信息 **/
            PDDocumentCatalog cata = document.getDocumentCatalog();
            List pages = cata.getAllPages();
            System.out.println(pages.size());
            int count = 1;
            for (int i = 0; i < pages.size(); i++) {
                PDPage page = (PDPage) pages.get(i);
                if (null != page) {
                    PDResources res = page.findResources();

                    //获取页面图片信息
                    Map imgs = res.getImages();
                    System.out.println(imgs);
                    if (null != imgs) {
                        Set keySet = imgs.keySet();
                        Iterator it = keySet.iterator();
                        while (it.hasNext()) {
                            Object obj = it.next();
                            PDXObjectImage img = (PDXObjectImage) imgs.get(obj);
                            img.write2file(imgSavePath + count);
                            count++;
                        }
                    }
                }
            }
        } catch (Exception e) {
            throw e;
        } finally {
            if (null != input)
                input.close();
            if (null != document)
                document.close();
        }
    }

    /**
     * 获取格式化后的时间信息
     *
     * @param dar 时间信息
     * @return
     * @throws Exception
     */
    public static String dateFormat(Calendar calendar) throws Exception {
        if (null == calendar)
            return null;
        String date = null;
        try {
            String pattern = DATE_FORMAT;
            SimpleDateFormat format = new SimpleDateFormat(pattern);
            date = format.format(calendar.getTime());
        } catch (Exception e) {
            throw e;
        }
        return date == null ? "" : date;
    }

    public static void main(String[] args) throws Exception {
        pdfParse("D:/test.pdf", "D:/img/");
    }
}