How to read PDF files in Java?

In this article I will show you how you can read PDF in Java, using JPedal’s PDF library.

How to read PDF files in Java

1. Add JPedal to your class or module path. (download the trial jar).
2. Extract text from a PDF file using the “ExtractTextInRectangle” class from the JPedal library in Java.
3. Extract text if the PDF is structured and tagged using the same “ExtractTextInRectangle” class.
4. Extract words from PDF in Java using JPedal library using the “ExtractTextAsWordlist”
5. Extract the document outline from a PDF file using the “ExtractOutline” class provided by the JPedal library
6. If the PDF requires a password to open, use the setPassword method before opening the file.
7. Download the PDF from the URL to your local system first and then apply the above extraction method.

What can I read from a PDF using Java?

You can read text, extract images, charts, forms, attachments, view PDF tables in Java and access metadata from a PDF file using various PDF processing tools and libraries available for different programming languages. This can also contain more complex content, like interactive elements, multimedia content, and code.

How can I read text from a PDF file?

You can use PDF libraries like JPedal that provide text extraction functionalities, which interpret the PDF’s content streams and extract the text. To extract and read PDF content in Java you can view our tutorial on How to extract text from PDF files in Java.

How is text stored in this file?

Text in a PDF is stored in a content stream which has lot of commands that select the font, define the characters via glyph indexes, and set their positions on the page. Text extraction is complex because it involves interpreting these commands rather than reading plain text. Specialized tools are required to parse content streams and accurately map glyphs to characters for extraction.

Is the text structured in a PDF file?

PDFs may contain structured text if they are tagged PDFs, which include information about the logical structure and reading order of the document’s content. We have a tutorial on how to find out if a PDF file contains Structured text.

How to read Metadata from a PDF file?

Metadata in a PDF, such as the author, title, and creation date, can be read using specialized PDF tools that can parse the document properties. If you want to read more about metadata, you can read our tutorial on How to access PDF file metadata.

How to read image from PDF in Java?

Images can be extracted from PDF files with the help of PDF libraries that can navigate to the image objects within the PDF’s internal structure. We have a detailed post on How to extract images from a PDF file.

Can I read a PDF file directly?

To read PDF using Java, you will need a Java PDF reader or a software library capable of interpreting the PDF format. This is because a PDF file is not plaintext like an HTML or TXT file. We have lots of tutorials explaining how to understand a PDF file.

How can I read text from an encrypted PDF file?

You need the correct password and a Java PDF reader. Once unlocked, you can view, copy, or export the text as needed. Always ensure you have the right permissions and legal grounds to access encrypted documents.

Viewer viewer = new Viewer();
viewer.setupViewer();
viewer.executeCommand(ViewerCommands.OPENFILE, "pdfFile.pdf");

//Convenience static method (see class for additional options)
ExtractClippedImages.writeAllClippedImagesToDir("inputFileOrDirectory", "outputDir", "outputImageFormat", new String[] {"imageHeightAsFloat", "subDirectoryForHeight"});

//Convenience static method (see class for additional options)
ExtractTextAsWordList.writeAllWordlistsToDir("inputFileOrDirectory", "outputDir", -1);

//Convenience static method (see class for additional options)
ArrayList resultsForPages = FindTextInRectangle.findTextOnAllPages("/path/to/file.pdf", "textToFind");

PrintPdfPages print = new PrintPdfPages("C:/pdfs/mypdf.pdf");

if (print.openPDFFile()) {
    print.printAllPages("Printer Name");
}

//Convenience static method (see class for additional options)
ExtractClippedImages.writeAllClippedImagesToDir("inputFileOrDirectory", "outputDir", "outputImageFormat", new String[] {"imageHeightAsFloat", "subDirectoryForHeight"});