springboot整合netty的多种方式

　　netty作为一个高性能的io框架，是非好用的一个技术框架，

　　Netty 是一个基于NIO的客户、服务器端编程框架，使用Netty 可以确保你快速和简单的开发出一个网络应用，例如实现了某种协议的客户、服务端应用。Netty相当于简化和流线化了网络应用的编程开发过程，例如：基于TCP和UDP的socket服务开发。
　　“快速”和“简单”并不用产生维护性或性能上的问题。Netty 是一个吸收了多种协议（包括FTP、SMTP、HTTP等各种二进制文本协议）的实现经验，并经过相当精心设计的项目。最终，Netty 成功的找到了一种方式，在保证易于开发的同时还保证了其应用的性能，稳定性和伸缩性
　　那么如何和springboot这个比较流行的框架进行整合呢？
　　首先整个项目引入pom
　　

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>2.2.1.RELEASE</version>

        <relativePath/> <!-- lookup parent from repository -->

    </parent>

    <groupId>com.cxy</groupId>

    <artifactId>netty</artifactId>

    <version>0.0.1-SNAPSHOT</version>

    <name>netty</name>

    <description>Demo project for Spring Boot</description>

    <properties>

        <java.version>1.8</java.version>

    </properties>

    <dependencies>

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-web</artifactId>

        </dependency>

        <dependency>

            <groupId>io.netty</groupId>

            <artifactId>netty-all</artifactId>

            <version>4.1.25.Final</version>

        </dependency>

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-test</artifactId>

            <scope>test</scope>

            <exclusions>

                <exclusion>

                    <groupId>org.junit.vintage</groupId>

                    <artifactId>junit-vintage-engine</artifactId>

                </exclusion>

            </exclusions>

        </dependency>

    </dependencies>

    <build>

        <plugins>

            <plugin>

                <groupId>org.springframework.boot</groupId>

                <artifactId>spring-boot-maven-plugin</artifactId>

            </plugin>

        </plugins>

    </build>

</project>

handler类是不会改变的

package com.cxy.netty.controller;

import io.netty.buffer.ByteBuf;

import io.netty.channel.ChannelFutureListener;

import io.netty.channel.ChannelHandlerContext;

import io.netty.channel.ChannelInboundHandlerAdapter;

import io.netty.util.CharsetUtil;

public class EchoServerHandler extends ChannelInboundHandlerAdapter {

    @Override

    public void channelRead(ChannelHandlerContext ctx, Object msg){

        ByteBuf in = (ByteBuf) msg;

        System.out.println("Server received: " + in.toString(CharsetUtil.UTF_8));

        ctx.write(in);

    }

    @Override

    public void channelReadComplete(ChannelHandlerContext ctx){

        ctx.writeAndFlush(ChannelFutureListener.CLOSE);

    }

    @Override

    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause){

        cause.printStackTrace();

        ctx.close();

    }

}

这个handler是我从官网上copy下来的

方式一：注解@PostConstruct

package com.cxy.netty.controller;

import io.netty.bootstrap.ServerBootstrap;

import io.netty.channel.ChannelFuture;

import io.netty.channel.ChannelInitializer;

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 org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.boot.autoconfigure.web.ServerProperties;

import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;

import javax.annotation.PreDestroy;

import java.net.InetSocketAddress;

@Component

public class NettyServer {

    /*private  int port =8080;

    public int getPort() {

        return port;

    }

    public void setPort(int port) {

        this.port = port;

    }

    public NettyServer(int port) {

        this.port = port;

    }*/

    @PostConstruct

    public void start() throws Exception {

        System.out.println("启动记载netty");

        EventLoopGroup boss = new NioEventLoopGroup();

        EventLoopGroup work = new NioEventLoopGroup();

        ServerBootstrap b = new ServerBootstrap();

        b.group(boss,work)

                .channel(NioServerSocketChannel.class)

                .localAddress(new InetSocketAddress(8082))

                .childHandler(new ChannelInitializer<SocketChannel>() {

                    @Override

                    protected void initChannel(SocketChannel ch) throws Exception {

                        ch.pipeline().addLast(new EchoServerHandler());

                    }

                });

        System.out.println("启动加载netty2");

        ChannelFuture channelFuturef = b.bind().sync();

        if (channelFuturef.isSuccess()){

        System.out.println("启动成功");

        }

    }

}

点击启动：

看日志：

说明已经启动

那么这个注解为什么这么神奇呢：

大概的意思，大家看下，意思就是这个方法会随着类的加载而加载，初始化加载的意思：

@Documented

@Retention (RUNTIME)

@Target(METHOD)

public @interface PostConstruct {

}

方式二：利用监听器启动：

package com.cxy.netty.controller;

import javax.servlet.ServletContextEvent;

import javax.servlet.ServletContextListener;

/**

 * 系统初始化监听器

 * @author Administrator

 *

 */

public class InitListener implements ServletContextListener {

    @Override

    public void contextInitialized(ServletContextEvent sce) {

        NettyServer nettyServer = new NettyServer(8081);

        try {

            nettyServer.start();

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

    @Override

    public void contextDestroyed(ServletContextEvent sce) {

    }

}

启动类：

package com.cxy.netty;

import com.cxy.netty.controller.InitListener;

import com.cxy.netty.controller.NettyServer;

import org.springframework.boot.CommandLineRunner;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.boot.web.servlet.ServletListenerRegistrationBean;

import org.springframework.context.annotation.Bean;

@SpringBootApplication

public class NettyApplication {

    /**

     * 注册监听器

     * @return

     */

    @SuppressWarnings({ "rawtypes", "unchecked" })

    @Bean

    public ServletListenerRegistrationBean servletListenerRegistrationBean() {

        ServletListenerRegistrationBean servletListenerRegistrationBean =

                new ServletListenerRegistrationBean();

        servletListenerRegistrationBean.setListener(new InitListener());

        return servletListenerRegistrationBean;

    }

    public static void main(String[] args) {

        SpringApplication.run(NettyApplication.class, args);

    }

}

看日志：

三：利用 ApplicationListener 上下文监听器

package com.cxy.netty.controller;

import com.cxy.netty.controller.NettyServer;

import org.springframework.context.ApplicationListener;

import org.springframework.context.event.ContextRefreshedEvent;

import org.springframework.stereotype.Component;

@Component

public class NettyBooter implements ApplicationListener<ContextRefreshedEvent> {

    @Override

    public void onApplicationEvent(ContextRefreshedEvent event) {

        NettyServer nettyServer = new NettyServer(8081);

        try {

            nettyServer.start();

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

}

启动类：

package com.cxy.netty;

import com.cxy.netty.controller.NettyServer;

import org.springframework.boot.CommandLineRunner;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.boot.web.servlet.ServletListenerRegistrationBean;

import org.springframework.context.annotation.Bean;

@SpringBootApplication

public class NettyApplication {

   /**

     * 注册监听器

     * @return

     */

   /* @SuppressWarnings({ "rawtypes", "unchecked" })

    @Bean

    public ServletListenerRegistrationBean servletListenerRegistrationBean() {

        ServletListenerRegistrationBean servletListenerRegistrationBean =

                new ServletListenerRegistrationBean();

        servletListenerRegistrationBean.setListener(new InitListener());

        return servletListenerRegistrationBean;

    }*/

    public static void main(String[] args) {

        SpringApplication.run(NettyApplication.class, args);

    }

}

看启动日志：

四：commiandLinerunner启动

package com.cxy.netty;

import com.cxy.netty.controller.NettyServer;

import org.springframework.boot.CommandLineRunner;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.boot.web.servlet.ServletListenerRegistrationBean;

import org.springframework.context.annotation.Bean;

/*

@SpringBootApplication

public class NettyApplication {

   */

/**

     * 注册监听器

     * @return

     *//*

   */

/* @SuppressWarnings({ "rawtypes", "unchecked" })

    @Bean

    public ServletListenerRegistrationBean servletListenerRegistrationBean() {

        ServletListenerRegistrationBean servletListenerRegistrationBean =

                new ServletListenerRegistrationBean();

        servletListenerRegistrationBean.setListener(new InitListener());

        return servletListenerRegistrationBean;

    }*//*

    public static void main(String[] args) {

        SpringApplication.run(NettyApplication.class, args);

    }

}

*/

@SpringBootApplication

public class NettyApplication implements CommandLineRunner {

    public static void main(String[] args) {

        SpringApplication.run(NettyApplication.class, args);

    }

    @Override

    public void run(String... args) throws Exception {

        NettyServer echoServer = new NettyServer(8083);

        echoServer.start();

    }

}