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netty入门实例

TimeServer.java

package netty.timeserver.server;import io.netty.bootstrap.ServerBootstrap;import io.netty.channel.ChannelFuture;import io.netty.channel.ChannelInitializer;import io.netty.channel.ChannelOption;import io.netty.channel.EventLoopGroup;import io.netty.channel.nio.NioEventLoopGroup;import io.netty.channel.socket.SocketChannel;import io.netty.channel.socket.nio.NioServerSocketChannel;public class TimeServer {    public void bind(int port) throws Exception {        EventLoopGroup bossGroup = new NioEventLoopGroup();        EventLoopGroup workerGroup = new NioEventLoopGroup();        try {            // 配置服务器的NIO线程租            ServerBootstrap b = new ServerBootstrap();            b.group(bossGroup, workerGroup)                    .channel(NioServerSocketChannel.class)                    .option(ChannelOption.SO_BACKLOG, 1024)                    .childHandler(new ChildChannelHandler());            // 绑定端口,同步等待成功            ChannelFuture f = b.bind(port).sync();            // 等待服务端监听端口关闭            f.channel().closeFuture().sync();        } finally {            // 优雅退出,释放线程池资源            bossGroup.shutdownGracefully();            workerGroup.shutdownGracefully();        }    }    private class ChildChannelHandler extends ChannelInitializer<SocketChannel> {        @Override        protected void initChannel(SocketChannel arg0) throws Exception {            System.out.println("server initChannel..");            arg0.pipeline().addLast(new TimeServerHandler());        }    }    public static void main(String[] args) throws Exception {        int port = 9000;        if (args != null && args.length > 0) {            try {                port = Integer.valueOf(args[0]);            } catch (NumberFormatException e) {            }        }        new TimeServer().bind(port);    }}

 

TimeServerHandler.java

package netty.timeserver.server;import java.util.Date;import io.netty.buffer.ByteBuf;import io.netty.buffer.Unpooled;import io.netty.channel.ChannelHandlerContext;import io.netty.channel.ChannelInboundHandlerAdapter;public class TimeServerHandler extends ChannelInboundHandlerAdapter {    @Override    public void channelRead(ChannelHandlerContext ctx, Object msg)            throws Exception {        System.out.println("server channelRead..");        ByteBuf buf = (ByteBuf) msg;        byte[] req = new byte[buf.readableBytes()];        buf.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());        ctx.write(resp);    }    @Override    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {        System.out.println("server channelReadComplete..");        ctx.flush();//刷新后才将数据发出到SocketChannel    }    @Override    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)            throws Exception {        System.out.println("server exceptionCaught..");        ctx.close();    }}

 

TimeClient.java

package netty.timeserver.client;import io.netty.bootstrap.Bootstrap;import io.netty.channel.ChannelFuture;import io.netty.channel.ChannelInitializer;import io.netty.channel.ChannelOption;import io.netty.channel.EventLoopGroup;import io.netty.channel.nio.NioEventLoopGroup;import io.netty.channel.socket.SocketChannel;import io.netty.channel.socket.nio.NioSocketChannel;public class TimeClient {    public void connect(int port, String host) throws Exception {        // 配置客户端NIO线程组        EventLoopGroup group = new NioEventLoopGroup();        try {            Bootstrap b = new Bootstrap();            b.group(group).channel(NioSocketChannel.class)                    .option(ChannelOption.TCP_NODELAY, true)                    .handler(new ChannelInitializer<SocketChannel>() {                        @Override                        protected void initChannel(SocketChannel arg0)                                throws Exception {                            System.out.println("client initChannel..");                            arg0.pipeline().addLast(new TimeClientHandler());                        }                    });            // 发起异步连接操作            ChannelFuture f = b.connect(host, port).sync();            // 等待客户端链路关闭            f.channel().closeFuture().sync();        } finally {            // 优雅退出,释放NIO线程组            group.shutdownGracefully();        }    }    public static void main(String[] args) throws Exception {        int port = 9000;        if (args != null && args.length > 0) {            try {                port = Integer.parseInt(args[0]);            } catch (Exception e) {            }        }        new TimeClient().connect(port, "127.0.0.1");    }}

 

TimeClientHandler.java

package netty.timeserver.client;import java.util.logging.Logger;import io.netty.buffer.ByteBuf;import io.netty.buffer.Unpooled;import io.netty.channel.ChannelHandlerContext;import io.netty.channel.ChannelInboundHandlerAdapter;public class TimeClientHandler extends ChannelInboundHandlerAdapter {    private static final Logger logger = Logger            .getLogger(TimeClientHandler.class.getName());    private final ByteBuf firstMessage;    public TimeClientHandler() {        byte[] req = "QUERY TIME ORDER".getBytes();        firstMessage = Unpooled.buffer(req.length);        firstMessage.writeBytes(req);    }    @Override    public void channelActive(ChannelHandlerContext ctx) throws Exception {        //与服务端建立连接后        System.out.println("client channelActive..");        ctx.writeAndFlush(firstMessage);    }    @Override    public void channelRead(ChannelHandlerContext ctx, Object msg)            throws Exception {        System.out.println("client channelRead..");        //服务端返回消息后        ByteBuf buf = (ByteBuf) msg;        byte[] req = new byte[buf.readableBytes()];        buf.readBytes(req);        String body = new String(req, "UTF-8");        System.out.println("Now is :" + body);    }    @Override    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)            throws Exception {        System.out.println("client exceptionCaught..");        // 释放资源        logger.warning("Unexpected exception from downstream:"                + cause.getMessage());        ctx.close();    }}