Java tutorial
/* * Copyright 2013-2018 Lilinfeng. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.book.netty5.codec; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandlerContext; import io.netty.handler.codec.MessageToByteEncoder; import java.io.IOException; import java.util.Map; import com.book.netty5.struct.NettyMessage; /** * @author Lilinfeng * @date 2014314 * @version 1.0 */ public final class NettyMessageEncoder extends MessageToByteEncoder<NettyMessage> { MarshallingEncoder marshallingEncoder; public NettyMessageEncoder() throws IOException { this.marshallingEncoder = new MarshallingEncoder(); } @Override protected void encode(ChannelHandlerContext ctx, NettyMessage msg, ByteBuf sendBuf) throws Exception { if (msg == null || msg.getHeader() == null) throw new Exception("The encode message is null"); sendBuf.writeInt((msg.getHeader().getCrcCode())); sendBuf.writeInt((msg.getHeader().getLength())); sendBuf.writeLong((msg.getHeader().getSessionID())); sendBuf.writeByte((msg.getHeader().getType())); sendBuf.writeByte((msg.getHeader().getPriority())); sendBuf.writeInt((msg.getHeader().getAttachment().size())); String key = null; byte[] keyArray = null; Object value = null; for (Map.Entry<String, Object> param : msg.getHeader().getAttachment().entrySet()) { key = param.getKey(); keyArray = key.getBytes("UTF-8"); sendBuf.writeInt(keyArray.length); sendBuf.writeBytes(keyArray); value = param.getValue(); marshallingEncoder.encode(value, sendBuf); } key = null; keyArray = null; value = null; if (msg.getBody() != null) { marshallingEncoder.encode(msg.getBody(), sendBuf); } else { sendBuf.writeInt(0); } sendBuf.setInt(4, sendBuf.readableBytes() - 8); } }