java实现查找PDF关键字所在页码及其坐标

红太狼 2023-06-01 12:38 7阅读 0赞

**1、因为最近有这方面的需求，用过之后记录一下。**

**2、此功能跟PDF中Ctrl+F性质一样，如果PDF中为图片形式的不支持定位到关键字。**

import com.itextpdf.awt.geom.Rectangle2D.Float;
    import com.itextpdf.text.pdf.PdfDictionary;
    import com.itextpdf.text.pdf.PdfName;
    import com.itextpdf.text.pdf.PdfReader;
    import com.itextpdf.text.pdf.parser.*;
    
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.IOException;
    import java.util.ArrayList;
    import java.util.List;
    
    /**
     * 消失的太阳
     */
    public class MyTest {
    
        public static void main(String[] args) throws IOException {
            //1.给定文件
            File pdfFile = new File("D://test.pdf");
            //2.定义一个byte数组，长度为文件的长度
            byte[] pdfData = new byte[(int) pdfFile.length()];
    
            //3.IO流读取文件内容到byte数组
            FileInputStream inputStream = null;
            try {
                inputStream = new FileInputStream(pdfFile);
                inputStream.read(pdfData);
            } catch (IOException e) {
                throw e;
            } finally {
                if (inputStream != null) {
                    try {
                        inputStream.close();
                    } catch (IOException e) {
                    }
                }
            }
    
            //4.指定关键字
            String keyword = "消失的太阳：";
    
            //5.调用方法，给定关键字和文件
            List<float[]> positions = findKeywordPostions(pdfData, keyword);
    
            //6.返回值类型是  List<float[]> 每个list元素代表一个匹配的位置，分别为 float[0]所在页码  float[1]所在x轴 float[2]所在y轴
            System.out.println("total:" + positions.size());
            if (positions != null && positions.size() > 0) {
                for (float[] position : positions) {
                    System.out.print("pageNum: " + (int) position[0]);
                    System.out.print("\tx: " + position[1]);
                    System.out.println("\ty: " + position[2]);
                }
            }
        }
    
    
        /**
         * findKeywordPostions
         * @param pdfData     通过IO流 PDF文件转化的byte数组
         * @param keyword     关键字
         * @return List<float [ ]> : float[0]:pageNum float[1]:x float[2]:y
         * @throws IOException
         */
        public static List<float[]> findKeywordPostions(byte[] pdfData, String keyword) throws IOException {
            List<float[]> result = new ArrayList<>();
            List<PdfPageContentPositions> pdfPageContentPositions = getPdfContentPostionsList(pdfData);
    
    
            for (PdfPageContentPositions pdfPageContentPosition : pdfPageContentPositions) {
                List<float[]> charPositions = findPositions(keyword, pdfPageContentPosition);
                if (charPositions == null || charPositions.size() < 1) {
                    continue;
                }
                result.addAll(charPositions);
            }
            return result;
        }
    
    
        private static List<PdfPageContentPositions> getPdfContentPostionsList(byte[] pdfData) throws IOException {
            PdfReader reader = new PdfReader(pdfData);
    
    
            List<PdfPageContentPositions> result = new ArrayList<>();
    
    
            int pages = reader.getNumberOfPages();
            for (int pageNum = 1; pageNum <= pages; pageNum++) {
                float width = reader.getPageSize(pageNum).getWidth();
                float height = reader.getPageSize(pageNum).getHeight();
    
    
                PdfRenderListener pdfRenderListener = new PdfRenderListener(pageNum, width, height);
    
    
                //解析pdf，定位位置
                PdfContentStreamProcessor processor = new PdfContentStreamProcessor(pdfRenderListener);
                PdfDictionary pageDic = reader.getPageN(pageNum);
                PdfDictionary resourcesDic = pageDic.getAsDict(PdfName.RESOURCES);
                try {
                    processor.processContent(ContentByteUtils.getContentBytesForPage(reader, pageNum), resourcesDic);
                } catch (IOException e) {
                    reader.close();
                    throw e;
                }
    
    
                String content = pdfRenderListener.getContent();
                List<CharPosition> charPositions = pdfRenderListener.getcharPositions();
    
    
                List<float[]> positionsList = new ArrayList<>();
                for (CharPosition charPosition : charPositions) {
                    float[] positions = new float[]{charPosition.getPageNum(), charPosition.getX(), charPosition.getY()};
                    positionsList.add(positions);
                }
    
    
                PdfPageContentPositions pdfPageContentPositions = new PdfPageContentPositions();
                pdfPageContentPositions.setContent(content);
                pdfPageContentPositions.setPostions(positionsList);
    
    
                result.add(pdfPageContentPositions);
            }
            reader.close();
            return result;
        }
    
    
        private static List<float[]> findPositions(String keyword, PdfPageContentPositions pdfPageContentPositions) {
    
    
            List<float[]> result = new ArrayList<>();
    
    
            String content = pdfPageContentPositions.getContent();
            List<float[]> charPositions = pdfPageContentPositions.getPositions();
    
    
            for (int pos = 0; pos < content.length(); ) {
                int positionIndex = content.indexOf(keyword, pos);
                if (positionIndex == -1) {
                    break;
                }
                float[] postions = charPositions.get(positionIndex);
                result.add(postions);
                pos = positionIndex + 1;
            }
            return result;
        }
    
    
        private static class PdfPageContentPositions {
            private String content;
            private List<float[]> positions;
    
    
            public String getContent() {
                return content;
            }
    
    
            public void setContent(String content) {
                this.content = content;
            }
    
    
            public List<float[]> getPositions() {
                return positions;
            }
    
    
            public void setPostions(List<float[]> positions) {
                this.positions = positions;
            }
        }
    
    
    
        private static class PdfRenderListener implements RenderListener {
            private int pageNum;
            private float pageWidth;
            private float pageHeight;
            private StringBuilder contentBuilder = new StringBuilder();
            private List<CharPosition> charPositions = new ArrayList<>();
    
    
            public PdfRenderListener(int pageNum, float pageWidth, float pageHeight) {
                this.pageNum = pageNum;
                this.pageWidth = pageWidth;
                this.pageHeight = pageHeight;
            }
    
    
            public void beginTextBlock() {
            }
    
    
            public void renderText(TextRenderInfo renderInfo) {
                List<TextRenderInfo> characterRenderInfos = renderInfo.getCharacterRenderInfos();
                for (TextRenderInfo textRenderInfo : characterRenderInfos) {
                    String word = textRenderInfo.getText();
                    if (word.length() > 1) {
                        word = word.substring(word.length() - 1, word.length());
                    }
                    Float rectangle = textRenderInfo.getAscentLine().getBoundingRectange();
    
                    float x = (float)rectangle.getX();
                    float y = (float)rectangle.getY();
    //                float x = (float)rectangle.getCenterX();
    //                float y = (float)rectangle.getCenterY();
    //                double x = rectangle.getMinX();
    //                double y = rectangle.getMaxY();
    
    
    
    
                    //这两个是关键字在所在页面的XY轴的百分比
                    float xPercent = Math.round(x / pageWidth * 10000) / 10000f;
                    float yPercent = Math.round((1 - y / pageHeight) * 10000) / 10000f;
    
    
    //                CharPosition charPosition = new CharPosition(pageNum, xPercent, yPercent);
                    CharPosition charPosition = new CharPosition(pageNum, (float)x, (float)y);
                    charPositions.add(charPosition);
                    contentBuilder.append(word);
                }
            }
    
    
            public void endTextBlock() {
            }
    
    
            public void renderImage(ImageRenderInfo renderInfo) {
            }
    
    
            public String getContent() {
                return contentBuilder.toString();
            }
    
    
            public List<CharPosition> getcharPositions() {
                return charPositions;
            }
        }
    
    
        private static class CharPosition {
            private int pageNum = 0;
            private float x = 0;
            private float y = 0;
    
    
            public CharPosition(int pageNum, float x, float y) {
                this.pageNum = pageNum;
                this.x = x;
                this.y = y;
            }
    
    
            public int getPageNum() {
                return pageNum;
            }
    
    
            public float getX() {
                return x;
            }
    
    
            public float getY() {
                return y;
            }
    
    
            @Override
            public String toString() {
                return "[pageNum=" + this.pageNum + ",x=" + this.x + ",y=" + this.y + "]";
            }
        }
    }

转载于:https://www.cnblogs.com/xsdty/p/11463174.html