The method putString(CharSequence, CharsetEncoder) from the type IoBuffer refers to the missing type CharSequence ?這是報錯的原因

String s = null;

if(message instanceof String){

s = (String)message;

}

if(s != null){

CharsetEncoder charsetEncoder = (CharsetEncoder)session.getAttribute("encoder");

if(charsetEncoder == null){

charsetEncoder = Charset.defaultCharset().newEncoder();

}

IoBuffer ioBuffer = IoBuffer.allocate(s.length());

ioBuffer.setAutoExpand(true);

ioBuffer.putString(s, charsetEncoder);

ioBuffer.flip();

out.write(ioBuffer);

}

這是我的代碼