工具类,直接拷贝就可以使用

import com.itextpdf.awt.geom.Rectangle2D;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.parser.ImageRenderInfo;
import com.itextpdf.text.pdf.parser.PdfReaderContentParser;
import com.itextpdf.text.pdf.parser.RenderListener;
import com.itextpdf.text.pdf.parser.TextRenderInfo;
import lombok.extern.slf4j.Slf4j;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * @Desc 工具类,查找关键字的坐标
 * @Author zr
 * @Date 2023/4/25 21:00
 * @Version 1.0
 */
@Slf4j
public class PdfFindKeyCoordinate1 {

    /**
     * filepath:文件路径加文件名
     * KEY_WORD:关键字 要求:(报表中关键字不能加粗,宋体,字号9)
     */
    private static int i = 1;
    static List<float[]> arrays = new ArrayList();
    static String sb ;
    /**
      * @Desc pdf中查找关键字的坐标
      * @Author zr
      * @Date 2023/4/27 10:38
      * @param filePath 文件路径
      * @param KEY_WORD 关键字
      * @return java.util.List 返回二位数组,查询到的所有关键字的坐标
     */
    public static List getKeyWordsCoordinate(String filePath, final String KEY_WORD) throws IOException {
        // 原PDF文件
        PdfReader pdfReader = new PdfReader(filePath);
        return getKeyWordsCoordinate(pdfReader,KEY_WORD);
    }
    /**
     * @Desc pdf中查找关键字的坐标
     * @Author zr
     * @Date 2023/4/27 10:38
     * @param inputStream pdf输入流
     * @param KEY_WORD 关键字
     * @return java.util.List  返回二位数组,查询到的所有关键字的坐标
     */
    public static List getKeyWordsCoordinate(ByteArrayInputStream inputStream, final String KEY_WORD) throws IOException {
        // 原PDF文件
        PdfReader reader = new PdfReader(inputStream);
        return getKeyWordsCoordinate(reader,KEY_WORD);
    }
    /**
      * @Desc pdf中查找关键字的坐标
      * @Author zr
      * @Date 2023/4/27 10:38
      * @param pdfReader  pdf文件读入器
      * @param KEY_WORD   关键字
      * @return java.util.List 返回二位数组,查询到的所有关键字的坐标
     */
    public static List getKeyWordsCoordinate(PdfReader pdfReader, final String KEY_WORD) throws IOException {
        arrays.clear();
        sb="";
        //获取PDF的页数
        int pageNum = pdfReader.getNumberOfPages();
        PdfReaderContentParser pdfReaderContentParser = new PdfReaderContentParser(
                pdfReader);
            for (i = 1; i <= pageNum; i++) {
                pdfReaderContentParser.processContent(i, new RenderListener() {
                    @Override
                    public void renderText(TextRenderInfo textRenderInfo) {
                        String text = textRenderInfo.getText(); // 整页内容

                        if (null != text && text.contains(KEY_WORD)) {
                            Rectangle2D.Float boundingRectange = textRenderInfo
                                    .getBaseline().getBoundingRectange();
                            sb = boundingRectange.x+"--"+boundingRectange.y+"---";

                            float[] resu = new float[3];
                            resu[0] = boundingRectange.x;
                            resu[1] = boundingRectange.y;
                            resu[2] = i;
                            arrays.add(resu);
                        }
                    }
                    @Override
                    public void renderImage(ImageRenderInfo arg0) {
                        // TODO Auto-generated method stub
                    }
                    @Override
                    public void endTextBlock() {
                        // TODO Auto-generated method stub
                    }
                    @Override
                    public void beginTextBlock() {
                        // TODO Auto-generated method stub
                    }
            });
        }
        return arrays;
    }
}

扩展:需要用到的maven jar包

<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itextpdf</artifactId>
    <version>5.5.10</version>
</dependency>
<dependency>
    <groupId>com.itextpdf.tool</groupId>
    <artifactId>xmlworker</artifactId>
    <version>5.5.10</version>
</dependency>

<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itext-asian</artifactId>
    <version>5.2.0</version>
</dependency>
<dependency>
    <groupId>org.xhtmlrenderer</groupId>
    <artifactId>flying-saucer-pdf-itext5</artifactId>
    <version>9.0.3</version>
    <exclusions>
        <exclusion>
            <artifactId>itextpdf</artifactId>
            <groupId>com.itextpdf</groupId>
        </exclusion>
    </exclusions>
</dependency>