一、什么是Echo服务和快速创建Netty项目
- 什么是Echo服务：就是一个应答服务（回显服务器），客户端发送什么数据，服务端就响应的对应的数据，是一个用于调试和检测的服务
- IDEA + Maven + jdk8 netty依赖包
- Maven地址： 点我前往
也可以用我的版本，我的版本是2022年7月
<!-- https://mvnrepository.com/artifact/io.netty/netty-all -->
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.79.Final</version>
</dependency>
二、Netty实战之Echo服务-服务端程序编写实战
EchoServer
package com.example.test05.demo.echo;
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;
public class EchoServer {
private int port;
public EchoServer(int port) {
this.port = port;
}
/**
* 启动流程
*/
public void run() throws InterruptedException {
//配置服务端线程组 两个线程组
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workGroup = new NioEventLoopGroup();
try {
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup, workGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new EchoServerHandler());
}
});
System.out.println("Echo 服务器启动ing");
//绑定端口，同步等待成功
ChannelFuture channelFuture = serverBootstrap.bind(port).sync();
//等待服务端监听端口关闭
channelFuture.channel().closeFuture().sync();
} finally {
//优雅退出，释放线程池
workGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
}
}
public static void main(String[] args) throws InterruptedException {
int port = 8080;
if (args.length > 0) {
port = Integer.parseInt(args[0]);
}
new EchoServer(port).run();
}
}
EchoServerHandler
package com.example.test05.demo.echo;
import io.netty.buffer.ByteBuf;
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) throws Exception {
ByteBuf data = (ByteBuf) msg;
System.out.println("服务端收到数据: "+ data.toString(CharsetUtil.UTF_8));
ctx.writeAndFlush(data);
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
System.out.println("EchoServerHandle channelReadComplete");
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}
三、Netty实战之Echo服务-客户端程序编写实战
EchoClient
package com.example.test05.demo.echo;
import io.netty.bootstrap.Bootstrap;
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.NioSocketChannel;
import java.net.InetSocketAddress;
public class EchoClient {
private String host;
private int port;
public EchoClient(String host, int port) {
this.host = host;
this.port = port;
}
public void start() throws InterruptedException {
EventLoopGroup group = new NioEventLoopGroup();
try {
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(group)
.channel(NioSocketChannel.class)
.remoteAddress(new InetSocketAddress(host, port))
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new EchoClientHandler());
}
});
//连接到服务端，connect是异步连接，在调用同步等待sync，等待连接成功
ChannelFuture channelFuture = bootstrap.connect().sync();
//阻塞直到客户端通道关闭
channelFuture.channel().closeFuture().sync();
} finally {
//优雅退出，释放NIO线程组
group.shutdownGracefully();
}
}
public static void main(String[] args) throws InterruptedException {
new EchoClient("127.0.0.1", 8081).start();
}
}
EchoClientHandler
package com.example.test05.demo.echo;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.util.CharsetUtil;
public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, ByteBuf msg) throws Exception {
System.out.println("Client received: " + msg.toString(CharsetUtil.UTF_8));
}
/**
* 激活之后运行
* @param ctx
* @throws Exception
*/
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
System.out.println("Active");
// 申请一个内存 Unpooled.copiedBuffer
ctx.writeAndFlush(Unpooled.copiedBuffer("DBC博客 www.dbc655.top",CharsetUtil.UTF_8));
}
/**
* 读取数据结束后
* @param ctx
* @throws Exception
*/
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
System.out.println("EchoClientHandler channelReadComplete");
}
/**
* 异常捕获的方法
* @param ctx
* @param cause
* @throws Exception
*/
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}
四、Netty实战之Echo服务演示和整个流程分析
简单的大话说明，详细请点击里面的文章
本文作者为DBC，转载请注明。
