Netty小demo(一)

实验

改造NIO实现的TimeServer

代码

• TimeServer

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;

/**
 * 时间协议服务端
 * Created by liqiushi on 2017/12/14.
 */
public class TimeServer {

    public static void main(String[] args) {
        //1、创建两个线程组 一个是接受连接，一个是用来处理连接
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        
        //2、需要一个辅助类ServerBootstrap
        ServerBootstrap b = new ServerBootstrap();
        
        b.group(bossGroup,workerGroup)
                .channel(NioServerSocketChannel.class) //创建ServerSocketChannel
                .option(ChannelOption.SO_BACKLOG,1024)
                //.childHandler(new ChildChannelHandler());
                .childHandler(new ChannelInitializer() {
                    @Override
                    protected void initChannel(SocketChannel ch) throws Exception {
                        ch.pipeline().addLast(new TimeServerHandler());
                    }
                });
        
        //3、绑定端口
        try {
            ChannelFuture f = b.bind(8001).sync();
            
            //4、等待服务端监听端口关闭
            f.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            //释放线程池资源
            System.out.println("release!");
            workerGroup.shutdownGracefully();
            bossGroup.shutdownGracefully();
        }
    }
}

• TimeServerHandler

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;

import java.util.Date;

/**
 * Created by liqiushi on 2017/12/14.
 */
public class TimeServerHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("connect established!");
        super.channelActive(ctx);
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf readBuf = (ByteBuf) msg;
        byte[] req = new byte[readBuf.readableBytes()];
        readBuf.readBytes(req);
        
        String body = new String(req,"UTF-8");
        System.out.println("The time server receive order :"+body);
        String currentTime = "QUERY TIME ORDER".equalsIgnoreCase(body)?
                new Date(System.currentTimeMillis()).toString():"BAD ORDER";
        ByteBuf resp = Unpooled.copiedBuffer(currentTime.getBytes());
        ChannelFuture f = ctx.writeAndFlush(resp);
        f.addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture future) {
                System.out.println("compeleted!");
                assert f == future;
                ctx.close();
            }
        }); 
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        super.exceptionCaught(ctx, cause);
    }
}