Barcodes are widely used in various industries for inventory management, retail, logistics, and more. Reading barcodes efficiently is crucial for automating data entry and improving accuracy. In Java, one of the most reliable libraries for barcode recognition is Spire.Barcode for Java. This article provides a comprehensive guide on how to read barcode in Java using this powerful library.

Table of Contents

• Introduction to Spire.Barcode for Java
• Key Features of Spire.Barcode
• Setting Up Spire.Barcode in Your Java Project
• Reading a Single Barcode from an Image File
• Reading Multiple Barcodes from One Image
• Customizing Barcode Recognition Settings
• Conclusion
• FAQs

Introduction to Spire.Barcode for Java

Spire.Barcode for Java is a robust library designed to generate and read barcodes in Java applications. It supports a wide range of barcode symbologies, including:

• 1D Barcodes : Code 128, Code 39, EAN-13, UPC-A, etc.
• 2D Barcodes : QR Code, DataMatrix, PDF417, etc.

Spire.Barcode provides fast and precise barcode recognition in Java, whether scanning from a dedicated barcode image or a complex image containing additional elements.

Key Features of Spire.Barcode

Before diving into implementation, let’s explore some key features of Spire.Barcode:

• Multi-Format Support : Read barcodes from PNG, JPG, BMP, GIF, and TIFF images.
• Batch Processing : Scan multiple barcodes in a single image.
• High Recognition Accuracy : Advanced algorithms ensure reliable barcode detection.
• Customizable Settings : Adjust scan regions and barcode types for optimized recognition.
• Cross-Platform Compatibility : Works seamlessly on Windows, Linux, and macOS.

These features make Spire.Barcode an excellent choice for enterprise-level barcode processing.

Setting Up Spire.Barcode in Your Java Project

To start reading barcodes in Java, you need to integrate Spire.Barcode into your project. Follow these steps:

Step 1: Install the Library

If you're using Maven, you can easily integrate Spire.Barcode by adding the following dependency to your pom.xml file:

<repositories>
    <repository>
        <id>com.e-iceblue</id>
        <name>e-iceblue</name>
        <url>https://repo.e-iceblue.com/nexus/content/groups/public/</url>
    </repository>
</repositories>
<dependency>
    <groupId>e-iceblue</groupId>
    <artifactId>spire.barcode</artifactId>
    <version>5.1.11</version>
</dependency>

For manual setup, download Spire.Barcode for Java from our website and add the downloaded .jar file to your project’s build path.

Step 2: Get a Temporary License

Spire.Barcode requires a license to read certain barcode types. To unlock full barcode recognition capabilities, get a free 30-day trial license. After receiving the license file, apply it using this code:

LicenseProvider.setLicenseKey("your license key");

Now, you're ready to read barcode in Java using Spire.Barcode.

Reading a Single Barcode from an Image File

Reading one barcode from an image is a fundamental scenario, and Spire.Barcode facilitates this with just a few lines of code.

Here’s a step-by-step example:

import com.spire.barcode.BarcodeScanner;
import com.spire.barcode.license.LicenseProvider;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

public class ReadBarcode {

    public static void main(String[] args) throws IOException {
        
        // Apply license key to remove restrictions on barcode types
        LicenseProvider.setLicenseKey("your license key");

        // Load the image file containing the barcode
        BufferedImage bufferedImage = ImageIO.read(new File("C:\\Users\\Administrator\\Desktop\\barcode.jpg "));

        // Scan the barcode from the loaded image
        String result = BarcodeScanner.scanOne(bufferedImage);

        // Output the scanned barcode result
        System.out.print(result);
    }
}

Explanation

• ImageIO.read() loads the image file, supporting extensions such as .png, .jpeg, .bmp, or .gif.
• BarcodeScanner.scanOne() detects and decodes the barcode from the image.
• The decoded result is stored in a String .

Note

The scanOne() method and the scan() method, which will be discussed later, can accept not only a BufferedImage as a parameter but also an InputStream and a String representing the image file path. Whether you're processing images from disk, user uploads, or real-time streams, this flexibility simplifies integration into diverse workflows.

Output:

Reading Multiple Barcodes from One Image

Spire.Barcode can detect and decode multiple barcodes in a single image. Here’s how:

import com.spire.barcode.BarcodeScanner;
import com.spire.barcode.license.LicenseProvider;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Arrays;

public class ReadMultipleBarcodes {

    public static void main(String[] args) throws IOException {

        // Apply license key to remove restrictions on barcode types
        LicenseProvider.setLicenseKey("your license key");

        // Load the image file containing the barcode
        BufferedImage bufferedImage = ImageIO.read(new File("C:\\Users\\Administrator\\Desktop\\barcodes.jpg"));

        // Scan the barcode from the loaded image
        String[] results = BarcodeScanner.scan(bufferedImage);

        // Output the results
        System.out.println(Arrays.toString(results));
    }
}

Explanation

• BarcodeScanner.scan() identifies and decodes all the barcodes present in the image.
• The results are stored in a String array .

Output:

Customizing Barcode Recognition Settings

For improved accuracy, Spire.Barcode allows you to customize scan settings, such as defining a scan region or specifying a particular barcode type. This enhanced approach ensures you have the flexibility and control needed for effective barcode scanning in Java.

Here is an example:

import com.spire.barcode.BarCodeType;
import com.spire.barcode.BarcodeScanner;
import com.spire.barcode.license.LicenseProvider;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

public class CustomScanSettings {

    public static void main(String[] args) throws IOException {

        // Apply license key to remove restrictions on barcode types
        LicenseProvider.setLicenseKey("your license key");

        // Load the image file containing the barcode
        BufferedImage bufferedImage = ImageIO.read(new File("C:\\Users\\Administrator\\Desktop\\barcodes.jpg"));

        // Define a rectangle area for barcode recognition
        Rectangle rectangle = new Rectangle(0,0,380,270);

        // Scan the barcode from the loaded image
        String[] results = BarcodeScanner.scan(bufferedImage, rectangle, BarCodeType.Code_93);

        // Output the first result
        System.out.print(results[0]);
    }
}

Explanation

• Rectangle() defines a specific area within the image for barcode recognition.
• BarCodeType enumeration allows you to specify the barcode type for more accurate detection.

Output:

Conclusion

In this article, we've explored the essential steps to set up Spire.Barcode in your Java project, read barcodes from images , handle multiple barcodes , and customize recognition settings for optimal accuracy. By leveraging these capabilities, developers can seamlessly integrate barcode scanning into their applications, improving data entry automation and reducing errors.

With Spire.Barcode, you have a reliable tool at your disposal to meet your barcode reading needs, paving the way for more efficient business operations.

FAQs

Q1. What types of barcodes can Spire.Barcode read?

Spire.Barcode supports 38+ barcode types, including both 1D barcodes like Code 128, Code 39, EAN-13, and UPC-A, as well as 2D barcodes such as QR Code, DataMatrix, and PDF417.

Q2. Can I customize the barcode scanning region?

Yes, Spire.Barcode allows you to define a specific scan area within the image by using a Rectangle object. This feature helps improve accuracy by focusing on a designated section of the image.

Q3. Can Spire.Barcode read multiple barcodes from a single image?

Yes! Using BarcodeScanner.scan(), you can detect and decode multiple barcodes in one image efficiently.

Q4. Is a license required to use Spire.Barcode for barcode recognition?

A commercial license is needed for full functionality, but you can get a free 30-day trial license to test all features before purchasing.

Q5. Can I use Spire.Barcode for Java to create barcodes?

Yes, Spire.Barcode supports generating over 38 commonly used 1D and 2D barcodes. For more information, check out: How to Create Barcode in Java

Reading Excel files using Java is a common requirement in enterprise applications, especially when dealing with reports, financial data, user records, or third-party integrations. Whether you're building a data import feature, performing spreadsheet analysis, or integrating Excel parsing into a web application, learning how to read Excel files in Java efficiently is essential.

In this tutorial, you’ll discover how to read .xls and .xlsx Excel files using Java. We’ll use practical Java code examples which also cover how to handle large files, read Excel files from InputStream, and extract specific content line by line.

Table of Contents

• 1. Set Up Your Java Project
• 2. How to Read XLSX and XLS Files in Java
  • Load and Read Excel File (XLSX or XLS)
  • Read Excel File Line by Line
  • Read Excel from InputStream
  • Read Cell Values in Different Formats
• 3. Best Practices for Large Excel Files
• 4. Full Example: Java Program to Read Excel File
• 5. Summary
• 6. FAQ

1. Set Up Your Java Project

To read Excel files using Java, you need a library that supports spreadsheet file formats. Spire.XLS for Java offers support for both .xls (legacy) and .xlsx (modern XML-based) files and provides a high-level API that makes Excel file reading straightforward.

Add Spire.XLS to Your Project

If you're using Maven, add the following to your pom.xml:

<repositories>
    <repository>
        <id>com.e-iceblue</id>
        <name>e-iceblue</name>
        <url>https://repo.e-iceblue.com/nexus/content/groups/public/</url>
    </repository>
</repositories>
<dependencies>
    <dependency>
        <groupId>e-iceblue</groupId>
        <artifactId>spire.xls</artifactId>
        <version>16.3.2</version>
    </dependency>
</dependencies>

If you're not using Maven, you can manually download the JAR from the official Spire.XLS website and add it to your classpath.

For smaller Excel processing tasks, you can also choose Free Spire.XLS for Java.

2. How to Read XLSX and XLS Files in Java

Java programs can easily read Excel files by loading the workbook and iterating through worksheets, rows, and cells. The .xlsx format is commonly used in modern Excel, while .xls is its older binary counterpart. Fortunately, Spire.XLS supports both formats seamlessly with the same code.

Load and Read Excel File (XLSX or XLS)

Here’s a basic example that loads an Excel file and prints its content:

import com.spire.xls.*;

public class ReadExcel {
    public static void main(String[] args) {
        // Create a workbook object and load the Excel file
        Workbook workbook = new Workbook();
        workbook.loadFromFile("data.xlsx"); // or "data.xls"

        // Get the first worksheet
        Worksheet sheet = workbook.getWorksheets().get(0);
        // Loop through each used row and column
        for (int i = 1; i <= sheet.getLastRow(); i++) {
            for (int j = 1; j <= sheet.getLastColumn(); j++) {
                // Get cell text of a cell range
                String cellText = sheet.getCellRange(i, j).getValue();
                System.out.print(cellText + "\t");
            }
            System.out.println();
        }
    }
}

You can replace the file path with an .xls file and the code remains unchanged. This makes it simple to read Excel files using Java regardless of format.

The Excel file being read and the output result shown in the console.

Read Excel File Line by Line with Row Objects

In scenarios like user input validation or applying business rules, processing each row as a data record is often more intuitive. In such cases, you can read the Excel file line by line using row objects via the getRows() method.

for (int i = 0; i < sheet.getRows().length; i++) {
    // Get a row
    CellRange row = sheet.getRows()[i];
    if (row != null && !row.isBlank()) {
        for (int j = 0; j < row.getColumns().length; j++) {
            String text = row.getColumns()[j].getText();
            System.out.print((text != null ? text : "") + "\t");
        }
        System.out.println();
    }
}

This technique works particularly well when reading Excel files in Java for batch operations or when you only need to process rows individually.

Read Excel File from InputStream

In web applications or cloud services, Excel files are often received as streams. Here’s how to read Excel files from an InputStream in Java:

import com.spire.xls.*;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;

public class ReadExcel {
    public static void main(String[] args) throws FileNotFoundException {
        // Create a InputStream
        InputStream stream = new FileInputStream("data.xlsx");
        // Load the Excel file from the stream
        Workbook workbook = new Workbook();
        workbook.loadFromStream(stream);
        System.out.println("Load Excel file successfully.");
    }
}

This is useful when handling file uploads, email attachments, or reading Excel files stored in remote storage.

Read Excel Cell Values in Different Formats

Once you load an Excel file and get access to individual cells, Spire.XLS allows you to read the contents in various formats—formatted text, raw values, formulas, and more.

Here's a breakdown of what each method does:

CellRange cell = sheet.getRange().get(2, 1); // B2

// Formatted text (what user sees in Excel)
String text = cell.getText();

// Raw string value
String value = cell.getValue();

// Generic object (number, boolean, date, etc.)
Object rawValue = cell.getValue2();

// Formula (if exists)
String formula = cell.getFormula();

// Evaluated result of the formula
String result = cell.getEnvalutedValue();

// If it's a number cell
double number = cell.getNumberValue();

// If it's a date cell
java.util.Date date = cell.getDateTimeValue();

// If it's a boolean cell
boolean bool = cell.getBooleanValue();

Tip: Use getValue2() for flexible handling, as it returns the actual underlying object. Use getText() when you want to match Excel's visible content.

You May Also Like: How to Write Data into Excel Files in Java

3. Best Practices for Reading Large Excel Files in Java

When your Excel file contains tens of thousands of rows or multiple sheets, performance can become a concern. To ensure your Java application reads large Excel files efficiently:

• Load only required sheets
• Access only relevant columns or rows
• Avoid storing entire worksheets in memory
• Use row-by-row reading patterns

Here’s an efficient pattern for reading only non-empty rows:

for (int i = 1; i <= sheet.getRows().length; i++) {
    Row row = sheet.getRows()[i];
    if (row != null && !row.isBlank()) {
        // Process only rows with data
    }
}

Even though Spire.XLS handles memory efficiently, following these practices helps scale your Java Excel reading logic smoothly.

See also: Delete Blank Rows and Columns in Excel Using Java

4. Full Example: Java Program to Read Excel File

Here’s a full working Java example that reads an Excel file (users.xlsx) with extended columns such as name, email, age, department, and status. The code extracts only the original three columns (name, email, and age) and filters the output for users aged 30 or older.

import com.spire.xls.*;

public class ExcelReader {
    public static void main(String[] args) {
        Workbook workbook = new Workbook();
        workbook.loadFromFile("users.xlsx");

        Worksheet sheet = workbook.getWorksheets().get(0);
        System.out.println("Name\tEmail\tAge");

        for (int i = 2; i <= sheet.getLastRow(); i++) {
            String name = sheet.getCellRange(i, 1).getValue();
            String email = sheet.getCellRange(i, 2).getValue();
            String ageText = sheet.getCellRange(i, 3).getValue();

            int age = 0;
            try {
                age = Integer.parseInt(ageText);
            } catch (NumberFormatException e) {
                continue;  // Skip rows with invalid age data
            }

            if (age >= 30) {
                System.out.println(name + "\t" + email + "\t" + age);
            }
        }
    }
}

Result of Java program reading the Excel file and printing its contents.

This code demonstrates how to read specific cells from an Excel file in Java and output meaningful tabular data, including applying filters on data such as age.

5. Summary

To summarize, this article showed you how to read Excel files in Java using Spire.XLS, including both .xls and .xlsx formats. You learned how to:

• Set up your Java project with Excel-reading capabilities
• Read Excel files using Java in row-by-row or stream-based fashion
• Handle legacy and modern Excel formats with the same API
• Apply best practices when working with large Excel files

Whether you're reading from an uploaded spreadsheet, a static report, or a stream-based file, the examples provided here will help you build robust Excel processing features in your Java applications.

If you want to unlock all limitations and experience the full power of Excel processing, you can apply for a free temporary license.

6. FAQ

Q1: How to read an Excel file dynamically in Java?

To read an Excel file dynamically in Java—especially when the number of rows or columns is unknown—you can use getLastRow() and getLastColumn() methods to determine the data range at runtime. This ensures that your program can adapt to various spreadsheet sizes without hardcoded limits.

Q2: How to extract data from Excel file in Java?

To extract data from Excel files in Java, load the workbook and iterate through the cells using nested loops. You can retrieve values with getCellRange(row, column).getValue(). Libraries like Spire.XLS simplify this process and support both .xls and .xlsx formats.

Q3: How to read a CSV Excel file in Java?

If your Excel data is saved as a CSV file, you can read it using Java’s BufferedReader or file streams. Alternatively, Spire.XLS supports CSV parsing directly—you can load a CSV file by specifying the separator, such as Workbook.loadFromFile("data.csv", ","). This lets you handle CSV files along with Excel formats using the same API.

Q4: How to read Excel file in Java using InputStream?

Reading Excel files from InputStream in Java is useful in server-side applications, such as handling file uploads. With Spire.XLS, simply call workbook.loadFromStream(inputStream) and process it as you would with any file-based Excel workbook.

In today's data-driven landscape, reading PDF files effectively is essential for Java developers. Whether you're handling scanned invoices, structured reports, or image-rich documents, the ability to read PDFs in Java can enhance workflows and reveal critical insights.

This guide will walk you through practical implementations using Spire.PDF for Java to master PDF reading in Java. You will learn to extract searchable text, retrieve embedded images, read tabular data, and perform OCR on scanned PDF documents.

Table of Contents:

• Java Library for Reading PDF Content
• Extract Text from Searchable PDFs
• Retrieve Images from PDFs
• Read Table Data from PDF Files
• Convert Scanned PDFs to Text via OCR
• Conclusion
• FAQs

Java Library for Reading PDF Content

When it comes to reading PDF in Java, choosing the right library is half the battle. Spire.PDF stands out as a robust, feature-rich solution for developers. It supports text extraction, image retrieval, table parsing, and even OCR integration. Its intuitive API and comprehensive documentation make it ideal for both beginners and experts.

To start extracting PDF content, download Spire.PDF for Java from our website and add it as a dependency in your project. If you’re using Maven, include the following in your pom.xml:

<repositories>
    <repository>
        <id>com.e-iceblue</id>
        <name>e-iceblue</name>
        <url>https://repo.e-iceblue.com/nexus/content/groups/public/</url>
    </repository>
</repositories>
<dependencies>
    <dependency>
        <groupId>e-iceblue</groupId>
        <artifactId>spire.pdf</artifactId>
        <version>11.5.2</version>
    </dependency>
</dependencies>

Below, we’ll explore how to leverage Spire.PDF for various PDF reading tasks.

Extract Text from Searchable PDFs in Java

Searchable PDFs store text in a machine-readable format, allowing for efficient content extraction. The PdfTextExtractor class in Spire.PDF provides a straightforward way to access page content, while PdfTextExtractOptions allows for flexible extraction settings, including options for handling special text layouts and specifying areas for extraction.

Step-by-Step Guide

1. Initialize a new instance of PdfDocument to work with your PDF file.
2. Use the loadFromFile method to load the desired PDF document.
3. Loop through each page of the PDF using a for loop.
4. For each page, create an instance of PdfTextExtractor to facilitate text extraction.
5. Create a PdfTextExtractOptions object to specify how text should be extracted, including any special strategies.
6. Call the extract method on the PdfTextExtractor instance to retrieve the text from the page.
7. Write the extracted text to a text file.

The example below shows how to retrieve text from every page of a PDF and output it to individual text files.

import com.spire.pdf.PdfDocument;
import com.spire.pdf.PdfPageBase;
import com.spire.pdf.texts.PdfTextExtractOptions;
import com.spire.pdf.texts.PdfTextExtractor;
import com.spire.pdf.texts.PdfTextStrategy;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class ExtractTextFromSearchablePdf {

    public static void main(String[] args) throws IOException {

        // Create a PdfDocument object
        PdfDocument doc = new PdfDocument();

        // Load a PDF file
        doc.loadFromFile("C:\\Users\\Administrator\\Desktop\\Input.pdf");

        // Iterate through all pages
        for (int i = 0; i < doc.getPages().getCount(); i++) {
            // Get the current page
            PdfPageBase page = doc.getPages().get(i);

            // Create a PdfTextExtractor object
            PdfTextExtractor textExtractor = new PdfTextExtractor(page);

            // Create a PdfTextExtractOptions object
            PdfTextExtractOptions extractOptions = new PdfTextExtractOptions();

            // Specify extract option
            extractOptions.setStrategy(PdfTextStrategy.None);

            // Extract text from the page
            String text = textExtractor.extract(extractOptions);

            // Define the output file path
            Path outputPath = Paths.get("output/Extracted_Page_" + (i + 1) + ".txt");

            // Write to a txt file
            Files.write(outputPath, text.getBytes());
        }

        // Close the document
        doc.close();
    }
}

Result:

Retrieve Images from PDFs in Java

The PdfImageHelper class in Spire.PDF enables efficient extraction of embedded images from PDF documents. It identifies images using PdfImageInfo objects, allowing for easy saving as standard image files.

Step-by-Step Guide

1. Initialize a new instance of PdfDocument to work with your PDF file.
2. Use the loadFromFile method to load the desired PDF.
3. Instantiate PdfImageHelper to assist with image extraction.
4. Loop through each page of the PDF.
5. For each page, retrieve all image information using the getImagesInfo method.
6. Loop through the retrieved image information, extract each image, and save it as a PNG file.

The following example extracts all embedded images from a PDF document and saves them as individual PNG files.

import com.spire.pdf.PdfDocument;
import com.spire.pdf.PdfPageBase;
import com.spire.pdf.utilities.PdfImageHelper;
import com.spire.pdf.utilities.PdfImageInfo;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

public class ExtractAllImages {

    public static void main(String[] args) throws IOException {

        // Create a PdfDocument object
        PdfDocument doc = new PdfDocument();

        // Load a PDF document
        doc.loadFromFile("C:\\Users\\Administrator\\Desktop\\Input.pdf");

        // Create a PdfImageHelper object
        PdfImageHelper imageHelper = new PdfImageHelper();

        // Declare an int variable
        int m = 0;

        // Iterate through the pages
        for (int i = 0; i < doc.getPages().getCount(); i++) {

            // Get a specific page
            PdfPageBase page = doc.getPages().get(i);

            // Get all image information from the page
            PdfImageInfo[] imageInfos = imageHelper.getImagesInfo(page);

            // Iterate through the image information
            for (int j = 0; j < imageInfos.length; j++)
            {
                // Get a specific image information
                PdfImageInfo imageInfo = imageInfos[j];

                // Get the image
                BufferedImage image = imageInfo.getImage();
                File file = new File(String.format("output/Image-%d.png",m));
                m++;

                // Save the image file in PNG format
                ImageIO.write(image, "PNG", file);
            }
        }

        // Clear up resources
        doc.dispose();
    }
}

Result:

Read Table Data from PDF Files in Java

For PDF tables that need conversion to structured data, PdfTableExtractor intelligently recognizes cell boundaries and relationships. The resulting PdfTable objects maintain the original table organization, allowing for cell-level data export.

Step-by-Step Guide

1. Initialize an instance of PdfDocument to handle your PDF file.
2. Use the loadFromFile method to open the desired PDF.
3. Instantiate PdfTableExtractor to facilitate table extraction.
4. Iterate through each page of the PDF to extract tables.
5. For each page, retrieve tables into a PdfTable array using the extractTable method.
6. For each table, iterate through its rows and columns to extract data.
7. Write the extracted data to individual text files.

This Java code extracts table data from a PDF document and saves each table as a separate text file.

import com.spire.pdf.PdfDocument;
import com.spire.pdf.utilities.PdfTable;
import com.spire.pdf.utilities.PdfTableExtractor;

import java.io.FileWriter;

public class ExtractTableData {
    public static void main(String[] args) throws Exception {

        // Create a PdfDocument object
        PdfDocument doc = new PdfDocument();

        // Load a PDF document
        doc.loadFromFile("C:\\Users\\Administrator\\Desktop\\Input.pdf");

        // Create a PdfTableExtractor instance
        PdfTableExtractor extractor = new PdfTableExtractor(doc);

        // Initialize a table counter
        int tableCounter = 1;

        // Loop through the pages in the PDF
        for (int pageIndex = 0; pageIndex < doc.getPages().getCount(); pageIndex++) {

            // Extract tables from the current page into a PdfTable array
            PdfTable[] tableLists = extractor.extractTable(pageIndex);

            // If any tables are found
            if (tableLists != null && tableLists.length > 0) {

                // Loop through the tables in the array
                for (PdfTable table : tableLists) {

                    // Create a StringBuilder for the current table
                    StringBuilder builder = new StringBuilder();

                    // Loop through the rows in the current table
                    for (int i = 0; i < table.getRowCount(); i++) {

                        // Loop through the columns in the current table
                        for (int j = 0; j < table.getColumnCount(); j++) {

                            // Extract data from the current table cell and append to the StringBuilder 
                            String text = table.getText(i, j);
                            builder.append(text).append(" | ");
                        }
                        builder.append("\r\n");
                    }

                    // Write data into a separate .txt document for each table
                    FileWriter fw = new FileWriter("output/Table_" + tableCounter + ".txt");
                    fw.write(builder.toString());
                    fw.flush();
                    fw.close();

                    // Increment the table counter
                    tableCounter++;
                }
            }
        }

        // Clear up resources
        doc.dispose();
    }
}

Result:

Convert Scanned PDFs to Text via OCR

Scanned PDFs require special handling through OCR engine such as Spire.OCR for Java. The solution first converts pages to images using Spire.PDF's rendering engine, then applies Spire.OCR's recognition capabilities via the OcrScanner class. This two-step approach effectively transforms physical document scans into editable text while supporting multiple languages.

Step 1. Install Spire.OCR and Configure the Environment

• Download Spire.OCR for Java and add the Jar file as a dependency in your project.
• Download the model that fits in with your operating system from one of the following links, and unzip the package somewhere on your disk.
  • Windowsx64
  • Linuxx64
  • macOS 10.15 and later-
• Configure the model in your code.

OcrScanner scanner = new OcrScanner();
configureOptions.setModelPath("D:\\win-x64");// model path

For detailed steps, refer to: Extract Text from Images Using the New Model of Spire.OCR for Java

Step 2. Convert a Scanned PDF to Text

This code example converts each page of a scanned PDF into an image, applies OCR to extract text, and saves the results in a text file.

import com.spire.ocr.OcrException;
import com.spire.ocr.OcrScanner;
import com.spire.ocr.ConfigureOptions;
import com.spire.pdf.PdfDocument;
import com.spire.pdf.graphics.PdfImageType;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class ExtractTextFromScannedPdf {

    public static void main(String[] args) throws IOException, OcrException {

        // Create an instance of the OcrScanner class
        OcrScanner scanner = new OcrScanner();

        // Configure the scanner
        ConfigureOptions configureOptions = new ConfigureOptions();
        configureOptions.setModelPath("D:\\win-x64"); // Set model path
        configureOptions.setLanguage("English"); // Set language

        // Apply the configuration options
        scanner.ConfigureDependencies(configureOptions);

        // Load a PDF document
        PdfDocument doc = new PdfDocument();
        doc.loadFromFile("C:\\Users\\Administrator\\Desktop\\Input.pdf");

        // Prepare temporary directory
        String tempDirPath = "temp";
        new File(tempDirPath).mkdirs(); // Create temp directory

        StringBuilder allText = new StringBuilder();

        // Iterate through all pages
        for (int i = 0; i < doc.getPages().getCount(); i++) {

            // Convert page to image
            BufferedImage bufferedImage = doc.saveAsImage(i, PdfImageType.Bitmap);
            String imagePath = tempDirPath + File.separator + String.format("page_%d.png", i);
            ImageIO.write(bufferedImage, "PNG", new File(imagePath));

            // Perform OCR
            scanner.scan(imagePath);
            String pageText = scanner.getText().toString();
            allText.append(String.format("\n--- PAGE %d ---\n%s\n", i + 1, pageText));

            // Clean up temp image
            new File(imagePath).delete();
        }

        // Save all extracted text to a file
        Path outputTxtPath = Paths.get("output", "extracted_text.txt");
        Files.write(outputTxtPath, allText.toString().getBytes());

        // Close the document
        doc.close();
        System.out.println("Text extracted to " + outputTxtPath);
    }
}

Conclusion

Mastering how to read PDF in Java opens up a world of possibilities for data extraction and document automation. Whether you’re dealing with searchable text, images, tables, or scanned documents, the right tools and techniques can simplify the process.

By leveraging libraries like Spire.PDF and integrating OCR for scanned files, you can build robust solutions tailored to your needs. Start experimenting with the code snippets provided and unlock the full potential of PDF processing in Java!

FAQs

Q1: Can I extract text from scanned PDFs using Java?

Yes, by combining Spire.PDF with Spire.OCR. Convert PDF pages to images and perform OCR to extract text.

Q2: What’s the best library for reading PDFs in Java?

Spire.PDF is highly recommended for its versatility and ease of use. It supports extraction of text, images, tables, and OCR integration.

Q3: Does Spire.PDF support extraction of PDF elements like metadata, attachments, and hyperlinks?

Yes, Spire.PDF provides comprehensive support for extracting:

• Metadata (title, author, keywords)
• Attachments (embedded files)
• Hyperlinks (URLs and document links)

The library offers dedicated classes like PdfDocumentInformation for metadata and methods to retrieve embedded files ( PdfAttachmentCollection ) and hyperlinks ( PdfUriAnnotation ).

Q4: How to parse tables from PDFs into CSV/Excel programmatically?

Using Spire.PDF for Java, you can extract table data from PDFs, then seamlessly export it to Excel (XLSX) or CSV format with Spire.XLS for Java. For a step-by-step guide, refer to our tutorial: Export Table Data from PDF to Excel in Java.

Get a Free License

To fully experience the capabilities of Spire.PDF for Java without any evaluation limitations, you can request a free 30-day trial license.