Netty4.0之codec

在上一篇文章中有分享了一个比较好的博客地址:http://asialee.iteye.com/blog/1769508

里面有详细介绍一些原理方面的知识,还有简单的使用。

而编码和解码,我想实现通过字符串,以“XXEE”作为分割符。

 

public final class Delimiters {

	public static ByteBuf[] XXEEDelimiter() {
		return new ByteBuf[] { Unpooled.wrappedBuffer("XXEE".getBytes()) };
	}

}

 

显而易见,返回XXEE的Delimiters。

 

public class PipelineFactory extends ChannelInitializer<SocketChannel> {

	private static final StringDecoder DECODER = new StringDecoder();
	private static final StringEncoder ENCODER = new StringEncoder(BufType.BYTE);
	private static final MessageCodec MSGCODEC = new MessageCodec();
	private static final TcpServerHandler TCPSERVERHANDLE = new TcpServerHandler();

	@Override
	public void initChannel(SocketChannel ch) throws Exception {
		ChannelPipeline pipeline = ch.pipeline();
		//不过滤分隔符
		pipeline.addLast("frame", new DelimiterBasedFrameDecoder(8192, false, Delimiters.XXEEDelimiter()));
		pipeline.addLast("decoder", DECODER);
		pipeline.addLast("encoder", ENCODER);
		//用MessageCodec过滤和组装分隔符
		pipeline.addLast("msgcodec", MSGCODEC);
		pipeline.addLast("handler", TCPSERVERHANDLE);
	}

}

 

MessageCodec实现如下:

 

@Sharable
public class MessageCodec extends MessageToMessageCodec<String, String> {

	@Override
	public String encode(ChannelHandlerContext ctx, String msg) throws Exception {
		return msg + "XXEE";
	}

	@Override
	public String decode(ChannelHandlerContext ctx, String msg) throws Exception {
		return msg.substring(0, msg.lastIndexOf("XXEE"));
	}

}

 

实现非常简单,通过分隔符过滤后,再用StringDecode转换成String,然后通过MessageCodec过滤分隔符。发消息时,反过来的流程。

 

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