juniversalchardet

What is it?

juniversalchardet is a Java port of "universalchardet", that is the encoding detector library of Mozilla.

Mozilla repo is available at http://hg.mozilla.org/mozilla-central/file/tip/extensions/universalchardet/

Encodings that can be detected

• Chinese

  • ISO-2022-CN
  • BIG-5
  • EUC-TW
  • HZ-GB-2312
  • GB-18030

• Cyrillic

  • ISO-8859-5
  • KOI8-R
  • WINDOWS-1251
  • MACCYRILLIC
  • IBM866
  • IBM855

• Greek

  • ISO-8859-7
  • WINDOWS-1253

• Hebrew

  • ISO-8859-8
  • WINDOWS-1255

• Japanese

  • ISO-2022-JP
  • Shift_JIS
  • EUC-JP

• Korean

  • ISO-2022-KR
  • EUC-KR

• Unicode

  • UTF-8
  • UTF-16BE / UTF-16LE
  • UTF-32BE / UTF-32LE / X-ISO-10646-UCS-4-3412 / X-ISO-10646-UCS-4-2143

• Others

  • WINDOWS-1252
  • US-ASCII

All supported encodings are listed in org.mozilla.universalchardet.Constants.

How to use it

(1) Construct an instance of org.mozilla.universalchardet.UniversalDetector.

(2) Feed some data (typically some thousand bytes) to the detector using UniversalDetector.handleData().

(3) Notify the detector of the end of data by using UniversalDetector.dataEnd().

(4) Get the detected encoding name by using UniversalDetector.getDetectedCharset().

(5) Don't forget to call UniversalDetector.reset() before you reuse the detector instance for another guess.

------------ Sample Code ------------

import org.mozilla.universalchardet.UniversalDetector;

public class TestDetector
{
  public static void main(String[] args)
  {
    byte[] buf = new byte[4096];
    java.io.InputStream fis = java.nio.file.Files.newInputStream(java.nio.file.Paths.get("test.txt"));

    // (1)
    UniversalDetector detector = new UniversalDetector();

    // (2)
    int nread;
    while ((nread = fis.read(buf)) > 0 && !detector.isDone()) {
      detector.handleData(buf, 0, nread);
    }
    // (3)
    detector.dataEnd();

    // (4)
    String encoding = detector.getDetectedCharset();
    if (encoding != null) {
      System.out.println("Detected encoding = " + encoding);
    } else {
      System.out.println("No encoding detected.");
    }

    // (5)
    detector.reset();
  }
}

Detecting encoding of a File (simple way)

import org.mozilla.universalchardet.UniversalDetector;

public class TestDetectorFile {

	public static void main (String[] args) throws java.io.IOException {
		if (args.length != 1) {
			System.err.println("Usage: java TestDetectorFile FILENAME");
			System.exit(1);
		}
		java.io.File file = new java.io.File(args[0]);
		String encoding = UniversalDetector.detectCharset(file);
		if (encoding != null) {
			System.out.println("Detected encoding = " + encoding);
		} else {
			System.out.println("No encoding detected.");
		}
	}
}

Creating a reader with correct encoding

import org.mozilla.universalchardet.ReaderFactory;

public class TestCreateReaderFromFile {
	
	public static void main (String[] args) throws java.io.IOException {
		if (args.length != 1) {
			System.err.println("Usage: java TestCreateReaderFromFile FILENAME");
			System.exit(1);
		}
	
		java.io.Reader reader = null;
		try {
			java.io.File file = new java.io.File(args[0]);
			reader = ReaderFactory.createBufferedReader(file);
			
			// Do whatever you want with the reader
		}
		finally {
			if (reader != null) {
				reader.close();
			}
		}
		
	}

}

Getting with maven

Put this dependency in your pom.xml

<dependency>
	<groupId>com.github.albfernandez</groupId>
	<artifactId>juniversalchardet</artifactId>
	<version>2.4.0</version>
</dependency>

Getting with gradle

Put this line in your build.gradle

implementation 'com.github.albfernandez:juniversalchardet:2.4.0'

Building from sources

    git clone https://github.com/albfernandez/juniversalchardet.git
    cd juniversalchardet
    mvn clean package

Related Works

• jchardet http://jchardet.sourceforge.net/

jchardet is another Java port of the Mozilla's encoding dectection library. The main difference between jchardet and juniversalchardet is modules they are based on. jchardet is based on the "chardet" module that has long existed. juniversalchardet is based on the "universalchardet" module that is new and generally provides better accuracy on detection results.

• juniversalchardet https://code.google.com/archive/p/juniversalchardet/

The original repository of this project

License

The library is subject to the Mozilla Public License Version 1.1.

Alternatively, the library may be used under the terms of either the GNU General Public License Version 2 or later, or the GNU Lesser General Public License 2.1 or later.

Compatibility

juniversalchardet requires JDK 7 or higher.

For Android:

• juniversalchardet 2.0.x requieres Android 4 (API Level 14)
• juniversalchardet 2.1.x and newer requires Android 8 (API Level 26)