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Extract any page number in PDF file with itextpdf

2022-07-23 22:34:00 【51CTO】

Now there is such a need ：

There are dozens of pages PDF file , Now you need to split the specified page number , And then you generate a new one PDF file .

This is the time , You can use open source itextpdf Library to implement ,itextpdf The official github The address is ： https://github.com/itext/itextpdf.

The following is a demonstration through specific code .

1、 Introduce dependencies

at present itextpdf The latest version is 5.5.13.3, Can be in https://search.maven.org/ Search the website .

<dependency>
    <groupId>com.itextpdf</groupId>
    <artifactId>itextpdf</artifactId>
    <version>5.5.13.3</version>
</dependency>

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2、 Code implementation

2.1 Specify page number extraction

package com.magic.itextpdf;

import java.io.FileOutputStream;
import java.io.IOException;
import java.util.List;
import java.util.Objects;

import com.itextpdf.text.Document;
import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.PdfCopy;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfSmartCopy;

/** * PDF Tool class  */
public class PdfUtils {

    /** *  extract PDF file  * @param sourceFile  Source PDF File path  * @param targetFile  The goal is PDF File path  * @param extractedPageNums  Page number to be extracted  */
    public static void extract(String sourceFile, String targetFile, List<Integer> extractedPageNums) {
        Objects.requireNonNull(sourceFile);
    	Objects.requireNonNull(targetFile);
        PdfReader reader = null;
        Document document = null;
        FileOutputStream outputStream = null;
        try {
            //  Read source file 
            reader = new PdfReader(sourceFile);
            //  Create a new document 
            document = new Document();
            //  Create goals PDF file 
            outputStream = new FileOutputStream(targetFile);
            PdfCopy pdfCopy = new PdfSmartCopy(document, outputStream);

            //  Get the number of pages of the source file 
            int pages = reader.getNumberOfPages();
            document.open();

            //  Note that the page number here is from 1 Start 
            for (int page = 1; page <= pages; page++) {
                //  If it is the designated page number , Copy it 
                if (extractedPageNums.contains(page)) {
                    pdfCopy.addPage(pdfCopy.getImportedPage(reader, page));
                }
            }
        } catch (IOException | DocumentException e) {
            e.printStackTrace();
        } finally {
            if (reader != null) {
                reader.close();
            }

            if (document != null) {
                document.close();
            }

            if (outputStream != null) {
                try {
                    outputStream.flush();
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

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extract() The method has three arguments , Subcontracting is the source PDF File path 、 The goal is PDF File path and specified page number , The designated page number is List Set to pass , For example, you need to extract the number 1 page , You can call... As follows

If you need to extract multiple pages at the same time , such as 1、3、5 page , So you can call

Of course , If one PDF There are more than 100 pages , Now we need to extract 10-60 page , If you still pass parameters as above , It will be very troublesome , At this point, you can overload a method , Realize the delivery of the start page number and end page number to extract .

2.2 Start and end page number extraction

heavy load extract Method , The specific code is as follows ：

/** *  extract PDF file  * @param sourceFile  Source PDF File path  * @param targetFile  The goal is PDF File path  * @param fromPageNum  Starting page number  * @param toPageNum  End page number  */
public static void extract(String sourceFile, String targetFile, int fromPageNum, int toPageNum) {
    Objects.requireNonNull(sourceFile);
    Objects.requireNonNull(targetFile);
    PdfReader reader = null;
    Document document = null;
    FileOutputStream outputStream = null;
    try {
        //  Read source file 
        reader = new PdfReader(sourceFile);
        //  Create a new document 
        document = new Document();
        //  Create goals PDF file 
        outputStream = new FileOutputStream(targetFile);
        PdfCopy pdfCopy = new PdfSmartCopy(document, outputStream);

        //  Get the number of pages of the source file 
        int pages = reader.getNumberOfPages();
        document.open();

        //  Note that the page number here is from 1 Start 
        for (int page = 1; page <= pages; page++) {
            if (page >= fromPageNum && page <= toPageNum) {
                pdfCopy.addPage(pdfCopy.getImportedPage(reader, page));
            }
        }
    } catch (IOException | DocumentException e) {
        e.printStackTrace();
    } finally {
        if (reader != null) {
            reader.close();
        }

        if (document != null) {
            document.close();
        }

        if (outputStream != null) {
            try {
                outputStream.flush();
                outputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

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For consecutive pages , This method is simpler , For example, to extract 10-60 page , So you can call

3、 Test verification

Now there is a total 2 page PDF file , Use the above methods to extract and split the second 1 page , The code is as follows ：

package com.magic.itextpdf;

import java.util.Collections;

public class Test {

    public static void main(String[] args) {
        PdfUtils.extract("D:\\Test\\test.pdf", "D:\\Test\\test_out_1.pdf", Collections.singletonList(1));
        PdfUtils.extract("D:\\Test\\test.pdf", "D:\\Test\\test_out_2.pdf", 1, 1);
    }
}

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After operation , Each generated test_out_1.pdf and test_out_2.pdf Two new files , New files are the first page of the source file .

4、 Other methods

If you only deal with a single PDF Word of the file , Then you can use WPS The printing function of , perhaps Chrome The printing function of the browser can be realized , Very convenient .