9.字符编码

public class NioTest13 {
    public static void main(String[] args) throws Exception {
        String inputFile = "NioTest13_in.txt";
        String outputFile = "NioTest13_out.txt";

        RandomAccessFile inputRandomAccessFile = new RandomAccessFile(inputFile, "r");
        RandomAccessFile outputRandomAccessFile = new RandomAccessFile(outputFile, "rw");

        long inputLength = new File(inputFile).length();

        FileChannel inputFileChannel = inputRandomAccessFile.getChannel();
        FileChannel outputFileChannel = outputRandomAccessFile.getChannel();

        MappedByteBuffer inputData = inputFileChannel.map(FileChannel.MapMode.READ_ONLY, 0, inputLength);

        Charset charset = Charset.forName("iso-8859-1");//utf-8

        CharsetEncoder encoder = charset.newEncoder();
        CharsetDecoder decoder = charset.newDecoder();

        CharBuffer charBuffer = decoder.decode(inputData);
        ByteBuffer byteBuffer = encoder.encode(charBuffer);

        outputFileChannel.write(byteBuffer);

        inputRandomAccessFile.close();
        outputRandomAccessFile.close();
    }
}