PDFTextExtract.java Source code

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Here is the source code for PDFTextExtract.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.text.PDFTextStripper;
import org.apache.pdfbox.text.TextPosition;

public class PDFTextExtract extends PDFTextStripper {

    private static ArrayList<Text> _tmp = new ArrayList<Text>();

    public String PDFFilePath;
    public String OutputFilepath;

    /**
     * Instantiate a new PDFTextStripper object.
     *
     * @throws IOException If there is an error loading the properties.
     */
    public PDFTextExtract() throws IOException {
    }

    public PDFTextExtract(String PDffilepath, String OutputFilepath) throws IOException {
        this.PDFFilePath = PDffilepath;
        this.OutputFilepath = OutputFilepath;
    }

    /**
     * This will parse the documents data.
     * 
     * @throws IOException If there is an error parsing the document.
     */
    public void process() throws IOException {
        PDDocument document = null;
        String res = null;
        OutputStream os = null;

        try {
            // Target PDF file.
            document = PDDocument.load(new File(this.PDFFilePath));

            // Extract Text from PDF ordered by page number.
            for (int i = 1; i <= document.getNumberOfPages(); i++) {
                System.out.println("processing page " + i + "...");
                _tmp.clear();
                PDFTextExtract stripper = new PDFTextExtract();

                // Tell PDFBox to sort the text positions.
                stripper.setSortByPosition(true);

                // Extract only one page.
                stripper.setStartPage(i);
                stripper.setEndPage(i);

                // Convert class `textPositions` into `Text`.
                // Save conversion result in `_tmp`.
                Writer dummy = new OutputStreamWriter(new ByteArrayOutputStream());
                stripper.writeText(document, dummy);

                // Skip if nothing converted.
                if (_tmp.isEmpty())
                    continue;

                // Concate result into string.
                for (Text now : _tmp) {
                    res += now.unicode;
                }
            }

            // Write result to file.
            os = new FileOutputStream(OutputFilepath);
            os.write(res.getBytes());
            System.out.println("processing completed.");
        } finally {
            if (document != null) {
                document.close();
            }
            if (os != null) {
                os.close();
            }
        }

    }

    /**
     * Override the default functionality of PDFTextStripper.
     */
    @Override

    protected void writeString(String _string, List<TextPosition> textPositions) throws IOException {
        for (TextPosition text : textPositions) {
            {
                _tmp.add(new Text(text.getXDirAdj(), text.getYDirAdj(), text.getFontSize(), text.getXScale(),
                        text.getHeightDir(), text.getWidthOfSpace(), text.getWidthDirAdj(), text.getUnicode()));
            }
        }
    }

    public class TextPositionComparator implements Comparator<TextPosition> {
        @Override
        public int compare(TextPosition pos1, TextPosition pos2) {
            int cmp1 = Float.compare(pos1.getDir(), pos2.getDir());
            if (cmp1 != 0) {
                return cmp1;
            }

            float x1 = pos1.getXDirAdj();
            float x2 = pos2.getXDirAdj();

            float pos1YBottom = pos1.getYDirAdj();
            float pos2YBottom = pos2.getYDirAdj();

            float pos1YTop = pos1YBottom - pos1.getHeightDir();
            float pos2YTop = pos2YBottom - pos2.getHeightDir();

            float yDifference = Math.abs(pos1YBottom - pos2YBottom);

            if (yDifference < 1. || pos2YBottom >= pos1YTop && pos2YBottom <= pos1YBottom
                    || pos1YBottom >= pos2YTop && pos1YBottom <= pos2YBottom) {
                return Float.compare(x1, x2);
            } else if (pos1YBottom < pos2YBottom) {
                return -1;
            } else {
                return 1;
            }
        }
    }
}