springboot整合netty，多种启动netty的方式，展现bean得多种启动方法

首先讲解下，spring中初始化加载问题：

很多时候，我们自己写的线程池，还有bean对象，还有其他的服务类，都可以通过，相关注解进行交给spring去管理，那么我们如何让nettyserver初始化加载呢：

在springBean的生命周期中有 

引入pom.xml

<?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>

1   InitializingBean  在系统初始化之后加载

package com.cxy.netty.controller;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.stereotype.Controller;

@Controller
public class DemoController implements InitializingBean {

    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("系统加载");
    }
}

我们可以看下日志：

"C:Program FilesJavajdk1.8.0_191injava.exe" -XX:TieredStopAtLevel=1 -noverify -Dspring.output.ansi.enabled=always -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=9135 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Djava.rmi.server.hostname=localhost -Dspring.liveBeansView.mbeanDomain -Dspring.application.admin.enabled=true "-javaagent:D:Program FilesJetBrainsideaIU-2018.1.2.winlibidea_rt.jar=9136:D:Program FilesJetBrainsideaIU-2018.1.2.winin" -Dfile.encoding=UTF-8 -classpath "C:Program FilesJavajdk1.8.0_191jrelibcharsets.jar;C:Program FilesJavajdk1.8.0_191jrelibdeploy.jar;C:Program FilesJavajdk1.8.0_191jrelibextaccess-bridge-64.jar;C:Program FilesJavajdk1.8.0_191jrelibextcldrdata.jar;C:Program FilesJavajdk1.8.0_191jrelibextdnsns.jar;C:Program FilesJavajdk1.8.0_191jrelibextjaccess.jar;C:Program FilesJavajdk1.8.0_191jrelibextjfxrt.jar;C:Program FilesJavajdk1.8.0_191jrelibextlocaledata.jar;C:Program FilesJavajdk1.8.0_191jrelibext
ashorn.jar;C:Program FilesJavajdk1.8.0_191jrelibextsunec.jar;C:Program FilesJavajdk1.8.0_191jrelibextsunjce_provider.jar;C:Program FilesJavajdk1.8.0_191jrelibextsunmscapi.jar;C:Program FilesJavajdk1.8.0_191jrelibextsunpkcs11.jar;C:Program FilesJavajdk1.8.0_191jrelibextzipfs.jar;C:Program FilesJavajdk1.8.0_191jrelibjavaws.jar;C:Program FilesJavajdk1.8.0_191jrelibjce.jar;C:Program FilesJavajdk1.8.0_191jrelibjfr.jar;C:Program FilesJavajdk1.8.0_191jrelibjfxswt.jar;C:Program FilesJavajdk1.8.0_191jrelibjsse.jar;C:Program FilesJavajdk1.8.0_191jrelibmanagement-agent.jar;C:Program FilesJavajdk1.8.0_191jrelibplugin.jar;C:Program FilesJavajdk1.8.0_191jrelib
esources.jar;C:Program FilesJavajdk1.8.0_191jrelib
t.jar;D:工作idea
etty	argetclasses;D:javamavenorgspringframeworkootspring-boot-starter-web2.2.1.RELEASEspring-boot-starter-web-2.2.1.RELEASE.jar;D:javamavenorgspringframeworkootspring-boot-starter2.2.1.RELEASEspring-boot-starter-2.2.1.RELEASE.jar;D:javamavenorgspringframeworkootspring-boot2.2.1.RELEASEspring-boot-2.2.1.RELEASE.jar;D:javamavenorgspringframeworkootspring-boot-autoconfigure2.2.1.RELEASEspring-boot-autoconfigure-2.2.1.RELEASE.jar;D:javamavenorgspringframeworkootspring-boot-starter-logging2.2.1.RELEASEspring-boot-starter-logging-2.2.1.RELEASE.jar;D:javamavenchqoslogbacklogback-classic1.2.3logback-classic-1.2.3.jar;D:javamavenchqoslogbacklogback-core1.2.3logback-core-1.2.3.jar;D:javamavenorgapachelogginglog4jlog4j-to-slf4j2.12.1log4j-to-slf4j-2.12.1.jar;D:javamavenorgapachelogginglog4jlog4j-api2.12.1log4j-api-2.12.1.jar;D:javamavenorgslf4jjul-to-slf4j1.7.29jul-to-slf4j-1.7.29.jar;D:javamavenjakartaannotationjakarta.annotation-api1.3.5jakarta.annotation-api-1.3.5.jar;D:javamavenorgyamlsnakeyaml1.25snakeyaml-1.25.jar;D:javamavenorgspringframeworkootspring-boot-starter-json2.2.1.RELEASEspring-boot-starter-json-2.2.1.RELEASE.jar;D:javamavencomfasterxmljacksoncorejackson-databind2.10.0jackson-databind-2.10.0.jar;D:javamavencomfasterxmljacksoncorejackson-annotations2.10.0jackson-annotations-2.10.0.jar;D:javamavencomfasterxmljacksoncorejackson-core2.10.0jackson-core-2.10.0.jar;D:javamavencomfasterxmljacksondatatypejackson-datatype-jdk82.10.0jackson-datatype-jdk8-2.10.0.jar;D:javamavencomfasterxmljacksondatatypejackson-datatype-jsr3102.10.0jackson-datatype-jsr310-2.10.0.jar;D:javamavencomfasterxmljacksonmodulejackson-module-parameter-names2.10.0jackson-module-parameter-names-2.10.0.jar;D:javamavenorgspringframeworkootspring-boot-starter-tomcat2.2.1.RELEASEspring-boot-starter-tomcat-2.2.1.RELEASE.jar;D:javamavenorgapache	omcatembed	omcat-embed-core9.0.27	omcat-embed-core-9.0.27.jar;D:javamavenorgapache	omcatembed	omcat-embed-el9.0.27	omcat-embed-el-9.0.27.jar;D:javamavenorgapache	omcatembed	omcat-embed-websocket9.0.27	omcat-embed-websocket-9.0.27.jar;D:javamavenorgspringframeworkootspring-boot-starter-validation2.2.1.RELEASEspring-boot-starter-validation-2.2.1.RELEASE.jar;D:javamavenjakartavalidationjakarta.validation-api2.0.1jakarta.validation-api-2.0.1.jar;D:javamavenorghibernatevalidatorhibernate-validator6.0.18.Finalhibernate-validator-6.0.18.Final.jar;D:javamavenorgjbossloggingjboss-logging3.4.1.Finaljboss-logging-3.4.1.Final.jar;D:javamavencomfasterxmlclassmate1.5.1classmate-1.5.1.jar;D:javamavenorgspringframeworkspring-web5.2.1.RELEASEspring-web-5.2.1.RELEASE.jar;D:javamavenorgspringframeworkspring-beans5.2.1.RELEASEspring-beans-5.2.1.RELEASE.jar;D:javamavenorgspringframeworkspring-webmvc5.2.1.RELEASEspring-webmvc-5.2.1.RELEASE.jar;D:javamavenorgspringframeworkspring-aop5.2.1.RELEASEspring-aop-5.2.1.RELEASE.jar;D:javamavenorgspringframeworkspring-context5.2.1.RELEASEspring-context-5.2.1.RELEASE.jar;D:javamavenorgspringframeworkspring-expression5.2.1.RELEASEspring-expression-5.2.1.RELEASE.jar;D:javamavenio
etty
etty-all4.1.25.Final
etty-all-4.1.25.Final.jar;D:javamavenorgslf4jslf4j-api1.7.29slf4j-api-1.7.29.jar;D:javamavenorgspringframeworkspring-core5.2.1.RELEASEspring-core-5.2.1.RELEASE.jar;D:javamavenorgspringframeworkspring-jcl5.2.1.RELEASEspring-jcl-5.2.1.RELEASE.jar" com.cxy.netty.NettyApplication

  .   ____          _            __ _ _
 /\ / ___'_ __ _ _(_)_ __  __ _    
( ( )\___ | '_ | '_| | '_ / _` |    
 \/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.2.1.RELEASE)

2019-11-23 18:20:49.749  INFO 38380 --- [           main] com.cxy.netty.NettyApplication           : Starting NettyApplication on LAPTOP-MEIVCU3E with PID 38380 (started by cxy in D:工作idea
etty)
2019-11-23 18:20:49.752  INFO 38380 --- [           main] com.cxy.netty.NettyApplication           : No active profile set, falling back to default profiles: default
2019-11-23 18:20:50.606  INFO 38380 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2019-11-23 18:20:50.623  INFO 38380 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2019-11-23 18:20:50.623  INFO 38380 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.27]
2019-11-23 18:20:50.736  INFO 38380 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2019-11-23 18:20:50.737  INFO 38380 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 947 ms
系统加载
2019-11-23 18:20:50.894  INFO 38380 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2019-11-23 18:20:51.029  INFO 38380 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2019-11-23 18:20:51.032  INFO 38380 --- [           main] com.cxy.netty.NettyApplication           : Started NettyApplication in 1.689 seconds (JVM running for 4.137)

打印出了系统加载，这个适合有时候系统停机导致内存中的数据会有少部分丢失，必须要在重启之后才调用相关服务才可以调用，才可以加载缓存，那么这个方法可以很有效的加载在jvm内存的数据

2  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 =8082;
    EventLoopGroup boss = new NioEventLoopGroup();
    EventLoopGroup work = new NioEventLoopGroup();

    @PostConstruct
    public void start() throws Exception {
        System.out.println("启动记载netty");
        ServerBootstrap b = new ServerBootstrap();
        b.group(boss,work)
                .channel(NioServerSocketChannel.class)
                .localAddress(new InetSocketAddress(port))
                .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");
        }


    }

    @PreDestroy
   private void destory() throws Exception{
        boss.shutdownGracefully();
        work.shutdownGracefully();
        System.out.println("关闭server");
        }
}

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 {
   
    public static void main(String[] args) {
        SpringApplication.run(NettyApplication.class, args);
    }

}

看打印日志：

 从这里代码又可以应征笔者之前说的，netty的使用只需要自己写好那个助手类就可以了；

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();
    }

}

 @PostConstruct  这个注解，到底是怎么样著有这么神奇的功效呢：

/**
 * The PostConstruct annotation is used on a method that needs to be executed
 * after dependency injection is done to perform any initialization. This
 * method MUST be invoked before the class is put into service. This
 * annotation MUST be supported on all classes that support dependency
 * injection. The method annotated with PostConstruct MUST be invoked even
 * if the class does not request any resources to be injected. Only one
 * method can be annotated with this annotation. The method on which the
 * PostConstruct annotation is applied MUST fulfill all of the following
 * criteria:

看到，表示，某个方法需要初始化的时候，可以使用这个注解：

 是作用到方法上面的，使用这个整合时候，需要注意问题，就是，我们需要将整个类交给spring去管理，这样，才可以进行初始化，这个类是在spring的包中，所以需要整合必须要用这个二注解。

3 基础类实现 CommandLineRunner 

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;

@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(8081);
        echoServer.start();
    }
}

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;

public class NettyServer {
    private  int port;

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }

    public NettyServer(int port) {
        this.port = port;
    }

    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(port))
                .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");
        }


    }

}

给他初始化的时候，添加启动方法，

看启动日志：

 注意事项,在nettyServer上不要加component注解

4 利用 ApplicationListener  上下文监听器

package com.cxy.netty;

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();
        }
    }
    
}

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;

@SpringBootApplication
public class NettyApplication {

    public static void main(String[] args) {
        SpringApplication.run(NettyApplication.class, args);
    }

}

看启动日志：

 可以看server也启动了。

5  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) {
        
    }

}

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：