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
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> 4.0.0 org.springframework.boot spring-boot-starter-parent 2.2.1.RELEASE com.cxy netty 0.0.1-SNAPSHOT netty Demo project for Spring Boot 1.8 org.springframework.boot spring-boot-starter-web io.netty netty-all 4.1.25.Final org.springframework.boot spring-boot-starter-test test org.junit.vintage junit-vintage-engine org.springframework.boot spring-boot-maven-plugin
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() { @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 {
@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(); } }
看日志：
代表这四种都可以启动成功，下章接再分析后面三种为什么可以启动成功