Springboot+Netty搭建基于TCP/IP协议的服务端（一）
<!-- netty依赖 springboot2.x自动导入版本 -->
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
</dependency>
NettyApplication.java
package com.mingshine.cloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableAsync;
@SpringBootApplication
@EnableAsync
@Configuration
public class NettyApplication {
public static void main(String[] args) {
SpringApplication.run(NettyApplication.class, args);
}
// @Async
// @Override
// public void run(String... args) throws Exception {
// new BootNettyServer().bind(8888);
// }
@Bean
public BootNettyServer mBootNettyServer() throws Exception {
BootNettyServer bootNettyServer = new BootNettyServer();
bootNettyServer.bind(8888);
return bootNettyServer;
}
}
BootNettyChannelInboundHandlerAdapter.java
package com.mingshine.cloud;
import java.io.IOException;
import java.net.InetSocketAddress;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
/**
* I/O数据读写处理类
*/
public class BootNettyChannelInboundHandlerAdapter extends ChannelInboundHandlerAdapter {
/**
* 从客户端收到新的数据时，这个方法会在收到消息时被调用
*
* @param ctx
* @param msg
*/
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception, IOException {
System.out.println("channelRead:read msg:" + msg.toString());
//回应客户端
ctx.write("I got it");
}
/**
* 从客户端收到新的数据、读取完成时调用
*
* @param ctx
*/
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws IOException {
System.out.println("channelReadComplete");
ctx.flush();
}
/**
* 当出现 Throwable 对象才会被调用，即当 Netty 由于 IO 错误或者处理器在处理事件时抛出的异常时
*
* @param ctx
* @param cause
*/
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws IOException {
System.out.println("exceptionCaught");
cause.printStackTrace();
ctx.close();//抛出异常，断开与客户端的连接
}
/**
* 客户端与服务端第一次建立连接时 执行
*
* @param ctx
* @throws Exception
*/
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception, IOException {
super.channelActive(ctx);
ctx.channel().read();
InetSocketAddress insocket = (InetSocketAddress) ctx.channel().remoteAddress();
String clientIp = insocket.getAddress().getHostAddress();
//此处不能使用ctx.close()，否则客户端始终无法与服务端建立连接
System.out.println("channelActive:" + clientIp + ctx.name());
}
/**
* 客户端与服务端 断连时 执行
*
* @param ctx
* @throws Exception
*/
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception, IOException {
super.channelInactive(ctx);
InetSocketAddress insocket = (InetSocketAddress) ctx.channel().remoteAddress();
String clientIp = insocket.getAddress().getHostAddress();
ctx.close(); //断开连接时，必须关闭，否则造成资源浪费，并发量很大情况下可能造成宕机
System.out.println("channelInactive:" + clientIp);
}
/**
* 服务端当read超时, 会调用这个方法
*
* @param ctx
* @param evt
* @throws Exception
*/
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception, IOException {
super.userEventTriggered(ctx, evt);
InetSocketAddress insocket = (InetSocketAddress) ctx.channel().remoteAddress();
String clientIp = insocket.getAddress().getHostAddress();
ctx.close();//超时时断开连接
System.out.println("userEventTriggered:" + clientIp);
}
@Override
public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
System.out.println("channelRegistered");
}
@Override
public void channelUnregistered(ChannelHandlerContext ctx) throws Exception {
System.out.println("channelUnregistered");
}
@Override
public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception {
System.out.println("channelWritabilityChanged");
}
}
BootNettyChannelInitializer.java
package com.mingshine.cloud;
import io.netty.channel.Channel;
import io.netty.channel.ChannelInitializer;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
/**
* 通道初始化
*/
public class BootNettyChannelInitializer<SocketChannel> extends ChannelInitializer<Channel> {
@Override
protected void initChannel(Channel ch) throws Exception {
// ChannelOutboundHandler，依照逆序执行
ch.pipeline().addLast("encoder", new StringEncoder());
// 属于ChannelInboundHandler，依照顺序执行
ch.pipeline().addLast("decoder", new StringDecoder());
/**
* 自定义ChannelInboundHandlerAdapter
*/
ch.pipeline().addLast(new BootNettyChannelInboundHandlerAdapter());
}
}
BootNettyServer.java
package com.mingshine.cloud;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.AdaptiveRecvByteBufAllocator;
import io.netty.channel.ChannelFuture;
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;
/**
* netty的server
*
*/
public class BootNettyServer {
public void bind(int port) throws Exception {
/**
* 配置服务端的NIO线程组
* NioEventLoopGroup 是用来处理I/O操作的Reactor线程组
* bossGroup：用来接收进来的连接，workerGroup：用来处理已经被接收的连接,进行socketChannel的网络读写，
* bossGroup接收到连接后就会把连接信息注册到workerGroup
* workerGroup的EventLoopGroup默认的线程数是CPU核数的二倍
*/
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
/**
* ServerBootstrap 是一个启动NIO服务的辅助启动类
*/
ServerBootstrap serverBootstrap = new ServerBootstrap();
/**
* 设置group，将bossGroup， workerGroup线程组传递到ServerBootstrap
*/
serverBootstrap = serverBootstrap.group(bossGroup, workerGroup);
/**
* ServerSocketChannel是以NIO的selector为基础进行实现的，用来接收新的连接，这里告诉Channel通过NioServerSocketChannel获取新的连接
*/
serverBootstrap = serverBootstrap.channel(NioServerSocketChannel.class);
/**
* option是设置 bossGroup，childOption是设置workerGroup
* netty 默认数据包传输大小为1024字节, 设置它可以自动调整下一次缓冲区建立时分配的空间大小，避免内存的浪费 最小 初始化 最大 (根据生产环境实际情况来定)
* 使用对象池，重用缓冲区
*/
serverBootstrap = serverBootstrap.option(ChannelOption.RCVBUF_ALLOCATOR, new AdaptiveRecvByteBufAllocator(64, 10496, 1048576));
serverBootstrap = serverBootstrap.childOption(ChannelOption.RCVBUF_ALLOCATOR, new AdaptiveRecvByteBufAllocator(64, 10496, 1048576));
/**
* 设置 I/O处理类,主要用于网络I/O事件，记录日志，编码、解码消息
*/
serverBootstrap = serverBootstrap.childHandler(new BootNettyChannelInitializer<SocketChannel>());
System.out.println("netty server start success!");
/**
* 绑定端口，同步等待成功
*/
ChannelFuture f = serverBootstrap.bind(port).sync();
/**
* 等待服务器监听端口关闭
*/
f.channel().closeFuture().sync();
} catch (InterruptedException e) {
} finally {
/**
* 退出，释放线程池资源
*/
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
