netty10---分包粘包

客户端：

package com.server;

import java.net.Socket;
import java.nio.ByteBuffer;

public class Client {

    public static void main(String[] args) throws Exception {
        Socket socket = new Socket("127.0.0.1", 10101);
        
        String message = "hello";
        
        byte[] bytes = message.getBytes();
        
        ByteBuffer buffer = ByteBuffer.allocate(4 + bytes.length);
        buffer.putInt(bytes.length);//netty是write,ByteBuffer是nio的，所以用put。
        buffer.put(bytes);
        
        byte[] array = buffer.array();
            
        for(int i=0; i<5; i++){
            socket.getOutputStream().write(array);
        }
            
        socket.close();
    }

}

服务端：

package com.server;

import java.net.InetSocketAddress;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import org.jboss.netty.bootstrap.ServerBootstrap;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelPipelineFactory;
import org.jboss.netty.channel.Channels;
import org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory;
import org.jboss.netty.handler.codec.string.StringDecoder;
import org.jboss.netty.handler.codec.string.StringEncoder;

public class Server {

    public static void main(String[] args) {
        //服务类
        ServerBootstrap bootstrap = new ServerBootstrap();
        //boss线程监听端口，worker线程负责数据读写
        ExecutorService boss = Executors.newCachedThreadPool();
        ExecutorService worker = Executors.newCachedThreadPool();
        //设置niosocket工厂
        bootstrap.setFactory(new NioServerSocketChannelFactory(boss, worker));
        //设置管道的工厂
        bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
            @Override
            public ChannelPipeline getPipeline() throws Exception {
                ChannelPipeline pipeline = Channels.pipeline();
                pipeline.addLast("decoder", new MyDecoder());
                pipeline.addLast("handler1", new HelloHandler());
                return pipeline;
            }
        });
        bootstrap.bind(new InetSocketAddress(10101));
        System.out.println("start!!!");
    }
}

package com.server;

import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.handler.codec.frame.FrameDecoder;

public class MyDecoder extends FrameDecoder {
    @Override  //FrameDecoder的decode方法
    protected Object decode(ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer) throws Exception {
        //buffer是netty的ChannelBuffer
        if(buffer.readableBytes() > 4){ //必须大于基本的最短长度4个字节
            if(buffer.readableBytes() > 2048){
                buffer.skipBytes(buffer.readableBytes());
            }
            //标记
            buffer.markReaderIndex();
            //长度
            int length = buffer.readInt();
            //buffer里面剩余的数据小于长度
            if(buffer.readableBytes() < length){
                //前面做了标记，这里可以还原
                buffer.resetReaderIndex();
                //缓存当前剩余的buffer数据，等待剩下数据包到来
                return null;
            }
            //大于长度，开始读数据
            byte[] bytes = new byte[length];
            buffer.readBytes(bytes);
            //往下传递对象给HelloHandler，这次的buffer处理完了，后面在来buffer的时候FrameDecoder会帮我们循环读取，
            return new String(bytes);
        }
        //缓存当前剩余的buffer数据，等待剩下数据包到来（FrameDecoder帮我们实现的），
        return null;
    }
}

package com.server;

import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelHandler;

public class HelloHandler extends SimpleChannelHandler {
    
    private int count = 1;//单线程的没有并发问题

    @Override
    public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
        System.out.println(e.getMessage() + "  " +count);
        count++;
    }
}