How to Integrate Tess4J OCR into a Spring Boot Application

1. Overview of OCR and Tess4J

Optical Character Recognition (OCR) transforms printed or handwritten text in documents, PDFs, or images into editable and searchable digital formats. A typical OCR pipeline consists of image preprocessing, text detection, feature extraction, character recognition, and post‑processing.

1.1 OCR workflow

Image preprocessing : acquisition, binarization, denoising, rotation correction, segmentation.

Text detection : locate text lines, words, or character boundaries.

Feature extraction : derive visual features used for recognition.

Character recognition : match extracted features against known character patterns.

Post‑processing : proofreading, formatting, layout analysis to improve readability.

1.2 Tesseract OCR

Tesseract is an open‑source OCR engine originally developed by HP and later sponsored by Google. It is one of the most accurate and widely used OCR engines.

1.3 Tess4J

Tess4J is a Java wrapper for the Tesseract engine, providing a simple API that allows Java applications to perform OCR without dealing with native code. Key characteristics include easy integration, cross‑platform support (Windows, macOS, Linux), full access to Tesseract features (multi‑language, custom training), and an active open‑source community.

2. Download language data

Language data files are hosted at https://github.com/tesseract-ocr/tessdata. For Chinese, download chi_sim.traineddata; for English, download eng.traineddata. Store the files in a directory of your choice and keep the .traineddata extension unchanged.

3. Integrate Tess4J into a Spring Boot project

3.1 Maven dependency

<dependency>
    <groupId>net.sourceforge.tess4j</groupId>
    <artifactId>tess4j</artifactId>
    <version>4.1.1</version>
</dependency>

3.2 Application configuration (application.yml)

server:
  port: 11014

tess4j:
  data-path: F:/HeiMaTouTiao/tessdata   # absolute path to the directory containing .traineddata files
  chinese-train-data: chi_sim
  english-train-data: eng

3.3 Configuration properties class

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;

@Configuration
@ConfigurationProperties(prefix = "tess4j")
public class Tess4jConfiguration {
    private String dataPath;
    private String chineseTrainData;
    private String englishTrainData;
    // getters and setters omitted for brevity
}

4. Test image recognition

4.1 Chinese text

Test code (JUnit) that loads a Chinese image and prints the OCR result together with the elapsed time.

import cn.edu.scau.config.Tess4jConfiguration;
import net.sourceforge.tess4j.ITesseract;
import net.sourceforge.tess4j.Tesseract;
import net.sourceforge.tess4j.TesseractException;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import java.io.File;

@SpringBootTest
public class Tess4jApplicationTests {
    @Autowired
    private Tess4jConfiguration tess4jConfiguration;

    @Test
    public void testChinese() throws TesseractException {
        long start = System.currentTimeMillis();
        ITesseract tesseract = new Tesseract();
        tesseract.setDatapath(tess4jConfiguration.getDataPath());
        tesseract.setLanguage(tess4jConfiguration.getChineseTrainData());
        File file = new File("F:/HeiMaTouTiao/tessdata/CaiXuKun-Chinese.png");
        String result = tesseract.doOCR(file);
        long end = System.currentTimeMillis();
        System.err.println("Time: " + (end - start) + " ms");
        System.out.println(result);
    }
}

Sample image:

4.2 English text

Similar test using the English language data.

@Test
public void testEnglish() throws TesseractException {
    long start = System.currentTimeMillis();
    ITesseract tesseract = new Tesseract();
    tesseract.setDatapath(tess4jConfiguration.getDataPath());
    tesseract.setLanguage(tess4jConfiguration.getEnglishTrainData());
    File file = new File("F:/HeiMaTouTiao/tessdata/CaiXuKun-English.png");
    String result = tesseract.doOCR(file);
    long end = System.currentTimeMillis();
    System.err.println("Time: " + (end - start) + " ms");
    System.out.println(result);
}

Sample image:

4.3 Mixed Chinese‑English text

When a document contains both Chinese and English characters, use the Chinese language data (which includes the English alphabet) to achieve combined recognition.

@Test
public void testChineseAndEnglish() throws TesseractException {
    long start = System.currentTimeMillis();
    ITesseract tesseract = new Tesseract();
    tesseract.setDatapath(tess4jConfiguration.getDataPath());
    tesseract.setLanguage(tess4jConfiguration.getChineseTrainData());
    File file = new File("F:/HeiMaTouTiao/tessdata/ParagraphWithChineseAndEnglish.png");
    String result = tesseract.doOCR(file);
    long end = System.currentTimeMillis();
    System.err.println("Time: " + (end - start) + " ms");
    System.out.println(result);
}

Sample image:

5. Precautions

The language data files must retain the .traineddata suffix, and the file name prefix (e.g., chi_sim, eng) must exactly match the language identifier used in the Java configuration. The data-path in application.yml must be an absolute directory path accessible to the application at runtime.