netty4.0之TCP的server与client初探（与3.X版本变化）DEMO

1.新建服务端java工程

lib中放入:

log4j-1.2.17.jar

netty-all-4.0.19.Final.jar

slf4j-api-1.7.7.jar

slf4j-log4j12-1.7.7.jar

2.TcpServer.java

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldPrepender;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.util.CharsetUtil;

import org.apache.log4j.Logger;

public class TcpServer {
    private static final Logger logger = Logger.getLogger(TcpServer.class);
    private static final String IP = "127.0.0.1";
    private static final int PORT = 9999;
    /** 用于分配处理业务线程的线程组个数 */
    protected static final int BIZGROUPSIZE = Runtime.getRuntime()
            .availableProcessors() * 2; // 默认
    /** 业务出现线程大小 */
    protected static final int BIZTHREADSIZE = 4;
    private static final EventLoopGroup bossGroup = new NioEventLoopGroup(BIZGROUPSIZE);
    private static final EventLoopGroup workerGroup = new NioEventLoopGroup(BIZTHREADSIZE);

    protected static void run() throws Exception {
        ServerBootstrap b = new ServerBootstrap();
        b.group(bossGroup, workerGroup);
        b.channel(NioServerSocketChannel.class);
        b.childHandler(new ChannelInitializer() {
            @Override
            public void initChannel(SocketChannel ch) throws Exception {
                ChannelPipeline pipeline = ch.pipeline();
                pipeline.addLast("frameDecoder",new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0,4, 0, 4));
                pipeline.addLast("frameEncoder", new LengthFieldPrepender(4));
                pipeline.addLast("decoder",new StringDecoder(CharsetUtil.UTF_8));
                pipeline.addLast("encoder",new StringEncoder(CharsetUtil.UTF_8));
                pipeline.addLast(new TcpServerHandler());
            }
        });

        b.bind(IP, PORT).sync();
        logger.info("TCP服务器已启动");
    }

    protected static void shutdown() {
        workerGroup.shutdownGracefully();
        bossGroup.shutdownGracefully();
    }

    public static void main(String[] args) throws Exception {
        logger.info("开始启动TCP服务器...");
        TcpServer.run();
        // TcpServer.shutdown();
    }
}

3.TcpServerHandler.java

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;

import org.apache.log4j.Logger;

public class TcpServerHandler extends SimpleChannelInboundHandler