在使用java里的ByteBuffer向FileChannel写入的时候无法写入的问题

在使用java里的ByteBuffer向FileChannel写入的时候无法写入的问题
代码如下

public static void main(String[] args) throws IOException {
        testChannelWrite( "channelWrite" + UUID.randomUUID().toString() + ".txt");
    }

public static void testChannelWrite(String filePath) throws IOException {
        RandomAccessFile fis = new RandomAccessFile(filePath, "rw");
        FileChannel channel = fis.getChannel();

        StringBuilder sb = new StringBuilder();
        ByteBuffer buffer = ByteBuffer.allocate(10_0000);

        for (int i = 1; i < 1_000_000; i++) {
            sb.append("你好");
        }

        if (sb.length() > 0)
            writeToChannel(buffer, channel, sb.toString());

        channel.close();
        fis.close();
    }

    private static void writeToChannel(ByteBuffer buffer, FileChannel channel, String s) throws IOException {
        buffer.clear();
        byte[] bytes = s.getBytes();

        int position = 0;

 // 循环把bytes数据写入channel
        while (position < bytes.length) {
            int writeSize = Math.min(buffer.remaining(), bytes.length - position);

            buffer.put(bytes, position, writeSize);
            // 记录当前在byte的位置
            position += writeSize;

            if (buffer.remaining() == 0) {
                channel.write(buffer);
                buffer.clear();
            }
        }

        if (buffer.remaining() != buffer.capacity()) {
            channel.write(buffer);
            channel.force(false);
            buffer.clear();
        }
    }

结果只能在文件中写入一次‘你好’，而我是循环了1000000次的。请问各位，这代码有什么问题吗

ByteBuffer.put之后调下ByteBuffer.flip试下