使用itext对pdf指定文字位置插入图片

原创知北行最后发布于2019-10-20 21:28:38 阅读数 144 收藏

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使用java开源itext库对pdf进行操作，分主要分两步先查找指定文字位置，然后再在指定位置插入图片。

1.查找指定文字的坐标位置

这里主要通过实现类RenderListener来完成查找坐标位置

代码如下：

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package com.anyu.PDFUtils;
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import java.io.File;
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import java.io.FileInputStream;
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import java.io.IOException;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.List;
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import com.itextpdf.awt.geom.Rectangle2D.Float;
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import com.itextpdf.text.Rectangle;
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import com.itextpdf.text.pdf.PdfDictionary;
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import com.itextpdf.text.pdf.PdfName;
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import com.itextpdf.text.pdf.PdfReader;
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import com.itextpdf.text.pdf.parser.ContentByteUtils;
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import com.itextpdf.text.pdf.parser.ImageRenderInfo;
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import com.itextpdf.text.pdf.parser.PdfContentStreamProcessor;
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import com.itextpdf.text.pdf.parser.RenderListener;
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import com.itextpdf.text.pdf.parser.TextRenderInfo;
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public class PdfKeywordFinder {
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    public static void main(String[] args) throws IOException {
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        String keyword = "甲方签字：";
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        List<float[]> positions = findKeywordPostions("E:\\Desktop\\pdftest.pdf", keyword);
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        System.out.println("total:" + positions.size());
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        if (positions != null && positions.size() > 0) {
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            for (float[] position : positions) {
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                System.out.print("pageNum: " + (int) position[0]);
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                System.out.print("\tx: " + position[1]);
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                System.out.println("\ty: " + position[2]);
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                System.out.println("\tcharWidth:" + position[3]);//每个字符的宽度
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            }
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        }
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    }
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    /**
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     * @description: 查找插入签名图片的最终位置，因为是插入签名图片，所以之前的关键字应只会出现一次
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     * 这里直接使用了第一次查找到关键字的位置，并返回该关键字之后的坐标位置
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     * @return: float[0]:页码，float[1]:最后一个字的x坐标，float[2]:最后一个字的y坐标
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     */
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    public static float[] getAddImagePositionXY(String pdfName, String keyword) throws IOException {
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        float[] temp = new float[3];
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        List<float[]> positions = PdfKeywordFinder.findKeywordPostions(pdfName, keyword);
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//        PdfReader pdfReader = new PdfReader(pdfName);
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//        Rectangle pageSize = pdfReader.getPageSize(1);
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//        temp[0]=positions.get(0)[0];
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//        temp[1]=positions.get(0)[1]*pageSize.getWidth();
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//        temp[2]=positions.get(0)[2]*pageSize.getHeight();
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        temp[0] = positions.get(0)[0];
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        temp[1] = positions.get(0)[1] + (keyword.length() * positions.get(0)[3]);
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        temp[2] = positions.get(0)[2] - positions.get(0)[3];
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        return temp;
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    }
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    /**
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     * findKeywordPostions
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     *  返回查找到关键字的首个文字的左上角坐标值
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     *
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     * @param pdfName
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     * @param keyword
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     * @return List<float [ ]> : float[0]:pageNum float[1]:x float[2]:y
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     * @throws IOException
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     */
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    public static List<float[]> findKeywordPostions(String pdfName, String keyword) throws IOException {
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        File pdfFile = new File(pdfName);
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        byte[] pdfData = new byte[(int) pdfFile.length()];
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        FileInputStream inputStream = new FileInputStream(pdfFile);
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        //从输入流中读取pdfData.length个字节到字节数组中，返回读入缓冲区的总字节数，若到达文件末尾，则返回-1
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        inputStream.read(pdfData);
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        inputStream.close();
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        List<float[]> result = new ArrayList<>();
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        List<PdfPageContentPositions> pdfPageContentPositions = getPdfContentPostionsList(pdfData);
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        for (PdfPageContentPositions pdfPageContentPosition : pdfPageContentPositions) {
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            List<float[]> charPositions = findPositions(keyword, pdfPageContentPosition);
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            if (charPositions == null || charPositions.size() < 1) {
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                continue;
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            }
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            result.addAll(charPositions);
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        }
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        return result;
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    }
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    private static List<PdfPageContentPositions> getPdfContentPostionsList(byte[] pdfData) throws IOException {
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        PdfReader reader = new PdfReader(pdfData);
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        List<PdfPageContentPositions> result = new ArrayList<>();
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        int pages = reader.getNumberOfPages();
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        for (int pageNum = 1; pageNum <= pages; pageNum++) {
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            float width = reader.getPageSize(pageNum).getWidth();
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            float height = reader.getPageSize(pageNum).getHeight();
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            PdfRenderListener pdfRenderListener = new PdfRenderListener(pageNum, width, height);
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//解析pdf，定位位置
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            PdfContentStreamProcessor processor = new PdfContentStreamProcessor(pdfRenderListener);
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            PdfDictionary pageDic = reader.getPageN(pageNum);
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            PdfDictionary resourcesDic = pageDic.getAsDict(PdfName.RESOURCES);
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            try {
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                processor.processContent(ContentByteUtils.getContentBytesForPage(reader, pageNum), resourcesDic);
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            } catch (IOException e) {
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                reader.close();
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                throw e;
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            }
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            String content = pdfRenderListener.getContent();
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            List<CharPosition> charPositions = pdfRenderListener.getcharPositions();
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            List<float[]> positionsList = new ArrayList<>();
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            for (CharPosition charPosition : charPositions) {
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                float[] positions = new float[]{charPosition.getPageNum(), charPosition.getX(), charPosition.getY(), charPosition.getCharWidth()};
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                positionsList.add(positions);
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            }
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            PdfPageContentPositions pdfPageContentPositions = new PdfPageContentPositions();
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            pdfPageContentPositions.setContent(content);
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            pdfPageContentPositions.setPostions(positionsList);
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            result.add(pdfPageContentPositions);
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        }
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        reader.close();
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        return result;
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    }
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    private static List<float[]> findPositions(String keyword, PdfPageContentPositions pdfPageContentPositions) {
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        List<float[]> result = new ArrayList<>();
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        String content = pdfPageContentPositions.getContent();
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        List<float[]> charPositions = pdfPageContentPositions.getPositions();
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        for (int pos = 0; pos < content.length(); ) {
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            int positionIndex = content.indexOf(keyword, pos);
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            if (positionIndex == -1) {
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                break;
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            }
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            float[] postions = charPositions.get(positionIndex);
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            result.add(postions);
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            pos = positionIndex + 1;
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        }
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        return result;
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    }
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    private static class PdfPageContentPositions {
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        private String content;
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        private List<float[]> positions;
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        public String getContent() {
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            return content;
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        }
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        public void setContent(String content) {
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            this.content = content;
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        }
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        public List<float[]> getPositions() {
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            return positions;
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        }
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        public void setPostions(List<float[]> positions) {
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            this.positions = positions;
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        }
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    }
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    private static class PdfRenderListener implements RenderListener {
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        private int pageNum;
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        private float pageWidth;
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        private float pageHeight;
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        private StringBuilder contentBuilder = new StringBuilder();
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        private List<CharPosition> charPositions = new ArrayList<>();
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        public PdfRenderListener(int pageNum, float pageWidth, float pageHeight) {
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            this.pageNum = pageNum;
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            this.pageWidth = pageWidth;
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            this.pageHeight = pageHeight;
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        }
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        @Override
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        public void beginTextBlock() {
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        }
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        @Override
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        public void renderText(TextRenderInfo renderInfo) {
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            List<TextRenderInfo> characterRenderInfos = renderInfo.getCharacterRenderInfos();
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            for (TextRenderInfo textRenderInfo : characterRenderInfos) {
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                String word = textRenderInfo.getText();
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                if (word.length() > 1) {
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                    word = word.substring(word.length() - 1, word.length());
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                }
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                Float rectangle = textRenderInfo.getAscentLine().getBoundingRectange();
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                float x = (float) rectangle.getMinX();
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                float y = (float) rectangle.getMinY();
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                float charWidth = (float) (rectangle.getMaxX() - rectangle.getMinX());
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                //也可以返回坐标相对于pdf页面大小的百分比
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                float xPercent = Math.round(x / pageWidth * 10000) / 10000f;
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                float yPercent = Math.round((1 - y / pageHeight) * 10000) / 10000f;
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                CharPosition charPosition = new CharPosition(pageNum, x, y, charWidth);
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                charPositions.add(charPosition);
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                contentBuilder.append(word);
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            }
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        }
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        @Override
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        public void endTextBlock() {
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        }
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        @Override
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        public void renderImage(ImageRenderInfo renderInfo) {
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        }
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        public String getContent() {
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            return contentBuilder.toString();
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        }
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        public List<CharPosition> getcharPositions() {
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            return charPositions;
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        }
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    }
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    private static class CharPosition {
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        private int pageNum = 0;
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        private float x = 0;
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        private float y = 0;
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        private float charWidth = 0;//单个文字的宽度
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        public CharPosition(int pageNum, float x, float y, float charWidth) {
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            this.pageNum = pageNum;
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            this.x = x;
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            this.y = y;
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            this.charWidth = charWidth;
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        }
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        public int getPageNum() {
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            return pageNum;
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        }
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        public float getX() {
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            return x;
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        }
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        public float getY() {
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            return y;
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        }
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        public float getCharWidth() {
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            return charWidth;
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        }
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        @Override
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        public String toString() {
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            return "[pageNum=" + this.pageNum + ",x=" + this.x + ",y=" + this.y + "]";
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        }
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    }
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}
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 复制

参考：Java 在pdf中通过关键字定位

2.在查找到的坐标位置插入图片

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package com.anyu;
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import com.anyu.PDFUtils.PdfKeywordFinder;
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import com.itextpdf.text.*;
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import com.itextpdf.text.pdf.PdfContentByte;
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import com.itextpdf.text.pdf.PdfReader;
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import com.itextpdf.text.pdf.PdfStamper;
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import com.itextpdf.text.pdf.PdfWriter;
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import java.io.FileOutputStream;
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import java.io.IOException;
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import java.net.URL;
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import java.util.Arrays;
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import java.util.List;
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/**
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 * @author ：fan
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 * @description: TODO
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 * @date ：2019/10/20 15:10
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 */
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public class PDFImageTest1 {
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    public static void main(String[] args) throws IOException, DocumentException {
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        String pdfname="E:\\Desktop\\pdftest.pdf";
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       //查找签名位置
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        float[] position= PdfKeywordFinder.getAddImagePositionXY(pdfname,"甲方签字：");
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        //Read file using PdfReader
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        PdfReader pdfReader = new PdfReader(pdfname);
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        System.out.println("x:"+position[1]+" y:"+position[2]);
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//        float pageNum=positions.get(0)[0];
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//        float x=positions.get(0)[1];
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//        float y=positions.get(0)[2];
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//        float charWidth=positions.get(0)[3];
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//        System.out.println(Arrays.toString(positions.get(0)));
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//        float temp[]=PdfKeywordFinder.getKeywordPositionXY(pdfname,"甲方签字");
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//        for(int i=0;i<temp.length;i++){
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//            System.out.println(temp[i]);
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//        }
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        //Modify file using PdfReader
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        PdfStamper pdfStamper = new PdfStamper(pdfReader, new FileOutputStream("E:\\Desktop\\modified.pdf"));
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        Image image = Image.getInstance("E:\\Desktop\\SignaturePicture\\testlogo.jpg");
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        //Fixed Positioning
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        image.scaleAbsolute(100, 50);
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        //Scale to new height and new width of image
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        image.setAbsolutePosition(position[1], position[2]);
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        System.out.println("pages:"+pdfReader.getNumberOfPages());
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        PdfContentByte content = pdfStamper.getUnderContent((int) position[0]);
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        content.addImage(image);
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        pdfStamper.close();
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    }
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}