java识别文件或字符串的编码格式

1, 用juniversalchardet：

http://code.google.com/p/juniversalchardet/

官方示例：

import org.mozilla.universalchardet.UniversalDetector;

public class TestDetector
{
  public static void main(String[] args)
  {
    byte[] buf = new byte[4096];
    java.io.FileInputStream fis = new java.io.FileInputStream("test.txt");

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

    // (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();
  }
}

他人示例代码:

public static String guessEncoding(byte[] bytes) {
    String DEFAULT_ENCODING = "UTF-8";
    org.mozilla.universalchardet.UniversalDetector detector =
        new org.mozilla.universalchardet.UniversalDetector(null);
    detector.handleData(bytes, 0, bytes.length);
    detector.dataEnd();
    String encoding = detector.getDetectedCharset();
    detector.reset();
    if (encoding == null) {
        encoding = DEFAULT_ENCODING;
    }
    return encoding;
}