如何使用Netty从服务器向客户端发送确认？

Question

Can any one explain how to send an acknowledgment from server to a device using netty .

I am using the following code:

public void messageReceived(ChannelHandlerContext ctx, MessageEvent e)
            throws Exception {

    String msg = null;
    String IMIE = null;
    String[] str = null;
    String ack = null;
    StringBuffer sbs = new StringBuffer();
    ChannelBuffer buf = (ChannelBuffer) e.getMessage();

    while(buf.readable()) {
        sbs.append((char) buf.readByte());          
    }

    msg = sbs.toString();
    System.out.println(msg);


    byte[] request = new byte[] { 0x01 };
    e.getChannel().write(request,e.getChannel().getRemoteAddress());
    System.out.flush(); 

and am getting error

java.lang.IllegalArgumentException: unsupported message type: class[B

Please, help me.

Answer 1

You need to wrap your byte array into an ChannelBuffer or add an Encoder that does this for you. So the simplest fix is this:

public void messageReceived(ChannelHandlerContext ctx, MessageEvent e)
        throws Exception {

    String msg = null;
    String IMIE = null;
    String[] str = null;
    String ack = null;
    ChannelBuffer buf = null;
    StringBuffer sbs = new StringBuffer();
    buf = (ChannelBuffer) e.getMessage();
    while(buf.readable()) {
        sbs.append((char) buf.readByte());
     }

    msg = sbs.toString();
    System.out.println(msg);


    byte[] request = new byte[] { 0x01 };
    e.getChannel().write(ChannelBuffers.wrappedBuffer(request));
    System.out.flush(); 
}