文本编码格式自动识别

public void parse(String uri) {
        File subtitlesFile = new File(uri);
        String line;
        FileInputStream is;
        BufferedReader in;
        try {
            is = new FileInputStream(subtitlesFile);
            in = getBufferedReader(is);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            return;
        }
        if (in != null) {
            try {
                while ((line = in.readLine()) != null) {
                    ... ...
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        } else {
            L.e(TAG, "readLine : read subtitle file fail.");
        }
    }

/**
 * 根据文本的前三个字节决定编码格式
**/
private BufferedReader getBufferedReader(FileInputStream fis) {
        BufferedReader reader = null;
        BufferedInputStream in = new BufferedInputStream(fis);
        in.mark(4);
        byte[] first3bytes = new byte[3];
        try {
            in.read(first3bytes);//找到文档的前三个字节并自动判断文档类型
            in.reset();
            if (first3bytes[0] == (byte) 0xEF && first3bytes[1] == (byte) 0xBB && first3bytes[2] == (byte) 0xBF) {
                reader = new BufferedReader(new InputStreamReader(in, "utf-8"));
            } else if (first3bytes[0] == (byte) 0xFF && first3bytes[1] == (byte) 0xFE) {
                reader = new BufferedReader(new InputStreamReader(in, "unicode"));
            } else if (first3bytes[0] == (byte) 0xFE && first3bytes[1] == (byte) 0xFF) {
                reader = new BufferedReader(new InputStreamReader(in, "utf-16be"));
            } else if (first3bytes[0] == (byte) 0xFF && first3bytes[1] == (byte) 0xFF) {
                reader = new BufferedReader(new InputStreamReader(in, "utf-16le"));
            } else {
                reader = new BufferedReader(new InputStreamReader(in, "GBK"));
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return reader;
    }