Netty入门案例

项目组要写一个心跳机制，用的netty3.x，所以就学习了一下netty，网上有很多例子，自己记录下做个参考，先把简单的例子跑通，后面再深入研究。

服务端Server启动代码

package com.netty3.demo;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;import java.net.InetSocketAddress;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;/** * Create by koma on 2017/11/27 */public class Server {    public static void main(String[] args) {        // Server启动类        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();                // 字符串编解码，如果传递的是自己自定义的bean类，可以使用ObjectDecoder和ObjectEncoder                pipeline.addLast("decoder", new StringDecoder());                pipeline.addLast("encoder", new StringEncoder());                pipeline.addLast("serverHandler", new ServerHandler());                return pipeline;            }        });        // 绑定到本机的端口号        bootstrap.bind(new InetSocketAddress(10086));        System.out.println("Server Start!!!");    }}

Server端处理的Handler

package com.netty3.demo;import org.jboss.netty.channel.*;/** * Create by koma on 2017/11/27 */public class ServerHandler extends SimpleChannelHandler {    // 消息处理    @Override    public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {        super.messageReceived(ctx, e);        // 可以直接强转，因为已经定义过了字符串编解码了        String s = (String) e.getMessage();        System.out.println("Server get message: "+s);        //回写到client数据        ctx.getChannel().write("Server already get your message!!");    }    // 异常处理    @Override    public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) throws Exception {        super.exceptionCaught(ctx, e);        System.out.println("出现异常了！！！");    }    // 建立新的连接触发    @Override    public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {        super.channelConnected(ctx, e);        System.out.println("连接建立");    }    // 连接已经建立，通道关闭触发    @Override    public void channelDisconnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {        super.channelDisconnected(ctx, e);        System.out.println("通道关闭！！");    }}

客户端Client启动类

package com.netty3.demo;import org.jboss.netty.bootstrap.ClientBootstrap;import org.jboss.netty.channel.*;import org.jboss.netty.channel.socket.nio.NioClientSocketChannelFactory;import org.jboss.netty.handler.codec.string.StringDecoder;import org.jboss.netty.handler.codec.string.StringEncoder;import java.net.InetSocketAddress;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;/** * Create by koma on 2017/11/27 */public class Client {    public static void main(String[] args) {        //服务类        ClientBootstrap bootstrap = new ClientBootstrap();        //线程池        ExecutorService boss = Executors.newCachedThreadPool();        ExecutorService worker = Executors.newCachedThreadPool();        //socket工厂        bootstrap.setFactory(new NioClientSocketChannelFactory(boss, worker));        //管道工厂        bootstrap.setPipelineFactory(new ChannelPipelineFactory() {            @Override            public ChannelPipeline getPipeline() throws Exception {                ChannelPipeline pipeline = Channels.pipeline();                pipeline.addLast("decoder", new StringDecoder());                pipeline.addLast("encoder", new StringEncoder());                pipeline.addLast("clientHandler", new ClientHandler());                return pipeline;            }        });        //连接服务端        ChannelFuture connect = bootstrap.connect(new InetSocketAddress("127.0.0.1", 10086));        Channel channel = connect.getChannel();        System.out.println("client start!!");        channel.write("hello, netty");//        bootstrap.releaseExternalResources();    }}

Client端Handler

package com.netty3.demo;import org.jboss.netty.channel.ChannelHandlerContext;import org.jboss.netty.channel.MessageEvent;import org.jboss.netty.channel.SimpleChannelHandler;/** * Create by koma on 2017/11/27 */public class ClientHandler extends SimpleChannelHandler {    // 只重写这一个方法了，ServerHandler已经重写过了    @Override    public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {        super.messageReceived(ctx, e);        // 收到从server端传来的信息        String str=(String)e.getMessage();        System.out.println("Client get mesage: " + str);    }}