Java NIO框架Netty教程(九)-Object对象编/解码

@Override
    protected Object encode(ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
        ChannelBufferOutputStream bout =
            new ChannelBufferOutputStream(dynamicBuffer(
                    estimatedLength, ctx.getChannel().getConfig().getBufferFactory()));
        bout.write(LENGTH_PLACEHOLDER);
        ObjectOutputStream oout = new CompactObjectOutputStream(bout);
        oout.writeObject(msg);
        oout.flush();
        oout.close();

        ChannelBuffer encoded = bout.buffer();
        encoded.setInt(0, encoded.writerIndex() - 4);
        return encoded;
    }

		* An encoder which serializes a Java object into a {@link ChannelBuffer}.<br />
		* <p><br />
		* Please note that the serialized form this encoder produces is not<br />
		* compatible with the standard {@link ObjectInputStream}.&nbsp; Please use<br />
		* {@link ObjectDecoder} or {@link ObjectDecoderInputStream} to ensure the<br />
		* interoperability with this encoder.</p>

/**
 * Object编码类
 * 
 * @author lihzh
 * @alia OneCoder
 * @blog http://www.coderli.com
 */
public class MyObjEncoder implements ChannelDownstreamHandler {

	@Override
	public void handleDownstream(ChannelHandlerContext ctx, ChannelEvent e)
			throws Exception {
		// 处理收发信息的情形
		if (e instanceof MessageEvent) {
			MessageEvent mEvent = (MessageEvent) e;
			Object obj = mEvent.getMessage();
			if (!(obj instanceof Command)) {
				ctx.sendDownstream(e);
				return;
			}
			ByteArrayOutputStream out = new ByteArrayOutputStream();
			ObjectOutputStream oos = new ObjectOutputStream(out);
			oos.writeObject(obj);
			oos.flush();
			oos.close();
			ChannelBuffer buffer = ChannelBuffers.dynamicBuffer();
			buffer.writeBytes(out.toByteArray());
			e.getChannel().write(buffer);
		} else {
			// 其他事件，自动流转。比如，bind，connected
			ctx.sendDownstream(e);
		}
	}
}

/**
 * Object解码类
 * 
 * @author lihzh
 * @alia OneCoder
 * @blog http://www.coderli.com
 */
public class MyObjDecoder implements ChannelUpstreamHandler {

	@Override
	public void handleUpstream(ChannelHandlerContext ctx, ChannelEvent e)
			throws Exception {
		if (e instanceof MessageEvent) {
			MessageEvent mEvent = (MessageEvent) e;
			if (!(mEvent.getMessage() instanceof ChannelBuffer)) {
				ctx.sendUpstream(mEvent);
				return;
			}
			ChannelBuffer buffer = (ChannelBuffer) mEvent.getMessage();
			ByteArrayInputStream input = new ByteArrayInputStream(buffer.array());
			ObjectInputStream ois = new ObjectInputStream(input);
			Object obj = ois.readObject();
			Channels.fireMessageReceived(e.getChannel(), obj);
		}
	}
}