Netty(十) Netty5.x 自定义编码解码器

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Netty(十) Netty5.x 自定义编码解码器

netty学习目录
一、Netty(一) NIO例子
二、Netty(二) netty服务端
三、Netty(三) Netty客户端+服务端
四、Netty(四) 简化版Netty源码
五、Netty(五)Netty5.x服务端
六、Netty(六) Netty Http 服务器例子
七、Netty(七) Netty服务端+客户端代码
八、Netty(八) Netty多客户端连接例子
九、Netty(九) Netty会话清除
十、Netty(十) Netty自定义编码器解码器
十一、Netty(十一) Netty对象传输

基于Netty5.x自定义编解码器

自定义消息实体

package com.zqw.netty5x.customproto;import java.io.Serializable;public class Header implements Serializable {private int tag;private int commandCode;private int version;private int length;public int getTag() {return tag;}public void setTag(int tag) {this.tag = tag;}public int getCommandCode() {return commandCode;}public void setCommandCode(int commandCode) {this.commandCode = commandCode;}public int getVersion() {return version;}public void setVersion(int version) {this.version = version;}public int getLength() {return length;}public void setLength(int length) {this.length = length;}@Overridepublic String toString() {return "Header{" +"tag=" + tag +", commandCode=" + commandCode +", version=" + version +", length=" + length +'}';}
}

package com.zqw.netty5x.customproto;import java.io.Serializable;public class Message implements Serializable {private Header header;private Object data;public Header getHeader() {return header;}public void setHeader(Header header) {this.header = header;}public Object getData() {return data;}public void setData(Object data) {this.data = data;}@Overridepublic String toString() {return "Message{" +"header=" + header +", data=" + data +'}';}
}

解码器

package com.zqw.netty5x.customproto;import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageDecoder;import java.util.List;public class MyDecoder extends ByteToMessageDecoder {private int MIN_LENGTH = 4 + 4 + 4 + 4;private int TAG = 1;private int MAX = 2048;@Overrideprotected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {if(in.readableBytes() <= MIN_LENGTH){return;}if(in.readableBytes() > MAX){in.skipBytes(in.readableBytes());}Message message = new Message();int tag = 0;while(true){in.markReaderIndex();if((tag = in.readInt()) == TAG){break;}in.resetReaderIndex();in.readByte();if(in.readableBytes() <= MIN_LENGTH){return;}}int commandCode = in.readInt();int version = in.readInt();int length = in.readInt();Header header = new Header();header.setCommandCode(commandCode);header.setLength(length);header.setTag(tag);header.setVersion(version);message.setHeader(header);byte[] bytes = new byte[length];if(length > 0){if(in.readableBytes() < length){//包还没齐，返回in.resetReaderIndex();return;}
//            System.out.println("bytebuffer可读的范围" + in.readableBytes());
//            if(in.readableBytes() > length){
//                in.resetReaderIndex();
//                System.out.println("返回了");
//                return;
//            }in.readBytes(bytes);String data = new String(bytes);message.setData(data);}out.add(message);}
}

编码器

package com.zqw.netty5x.customproto;import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToByteEncoder;public class MyEncoder extends MessageToByteEncoder<Message> {@Overrideprotected void encode(ChannelHandlerContext ctx, Message msg, ByteBuf out) throws Exception {if(msg == null || msg.getHeader() == null){throw new Exception("the encode message is null");}Header header = msg.getHeader();int tag = header.getTag();int commandCode = header.getCommandCode();int version = header.getVersion();int length = header.getLength();Object data = msg.getData();out.writeInt(tag);out.writeInt(commandCode);out.writeInt(version);out.writeInt(0);if(data != null){String str = (String) data;byte[] bytes = str.getBytes();length = bytes.length;out.writeBytes(bytes);}//写入length;out.setInt(12, length);}
}