判断文件的编码类型

GetFilecharset.java

public static String getFilecharset(File sourceFile) {
  String charset = "GBK";
  byte[] first3Bytes = new byte[3];
  try {
    BufferedInputStream bis = new BufferedInputStream(new FileInputStream(sourceFile));
    bis.mark(0);
    int read = bis.read(first3Bytes, 0, 3);
    System.out.println("字节大小："+read);
    if (read == -1) {
      return charset; //文件编码为 ANSI
    } else if (first3Bytes[0] == (byte) 0xFF
               && first3Bytes[1] == (byte) 0xFE) {
      charset = "UTF-16LE"; //文件编码为 Unicode
    } else if (first3Bytes[0] == (byte) 0xFE
               && first3Bytes[1] == (byte) 0xFF) {
      charset = "UTF-16BE"; //文件编码为 Unicode big endian
    } else if (first3Bytes[0] == (byte) 0xEF
               && first3Bytes[1] == (byte) 0xBB
               && first3Bytes[2] == (byte) 0xBF) {
      charset = "UTF-8"; //文件编码为 UTF-8
    }
    bis.reset();
    bis.close();
  } catch (Exception e) {
    e.printStackTrace();
  }
  return charset;
}