概述
netty 5 已经放弃掉了,作为学习netty4和5的差别不大,本例子是基于netty5
https://github.com/netty/netty/issues/4466
线程安全
一个thread + 队列 == 一个单线程线程池。线程安全的，任务是线性串行执行的
线程安全，不会产生阻塞效应 ，使用对象组
线程不安全，会产生阻塞效应， 使用对象池
Figure 1. 对象池
Figure 2. 对象组
writeAndFlush 发送消息线程安全
其中 EventExecutor executor 是 NioEventLoop 线程安全
public final class NioEventLoop extends SingleThreadEventLoop
代码
Server
/**
* netty5服务端
*
*
*/
public class Server {
public static void main(String[] args) {
//服务类
ServerBootstrap bootstrap = new ServerBootstrap();
//boss和worker
EventLoopGroup boss = new NioEventLoopGroup();
EventLoopGroup worker = new NioEventLoopGroup();
try {
//设置线程池
bootstrap.group(boss, worker);
//设置socket工厂、
bootstrap.channel(NioServerSocketChannel.class);
//设置管道工厂
bootstrap.childHandler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
ch.pipeline().addLast(new StringDecoder());
ch.pipeline().addLast(new StringEncoder());
ch.pipeline().addLast(new ServerHandler());
}
});
//netty3中对应设置如下
//bootstrap.setOption("backlog", 1024);
//bootstrap.setOption("tcpNoDelay", true);
//bootstrap.setOption("keepAlive", true);
//设置参数，TCP参数
bootstrap.option(ChannelOption.SO_BACKLOG, 2048);//serverSocketchannel的设置，链接缓冲池的大小
bootstrap.childOption(ChannelOption.SO_KEEPALIVE, true);//socketchannel的设置,维持链接的活跃，清除死链接
bootstrap.childOption(ChannelOption.TCP_NODELAY, true);//socketchannel的设置,关闭延迟发送
//绑定端口
ChannelFuture future = bootstrap.bind(10101);
System.out.println("start");
//等待服务端关闭
future.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
} finally{
//释放资源
boss.shutdownGracefully();
worker.shutdownGracefully();
}
}
}
ServerHandler
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
/**
* 服务端消息处理
*
*
*/
public class ServerHandler extends SimpleChannelInboundHandler<String> {
@Override
protected void messageReceived(ChannelHandlerContext ctx, String msg) throws Exception {
System.out.println(msg);
ctx.channel().writeAndFlush("hi");
ctx.writeAndFlush("hi");
}
/**
* 新客户端接入
*/
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
System.out.println("channelActive");
}
/**
* 客户端断开
*/
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
System.out.println("channelInactive");
}
/**
* 异常
*/
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
}
}
Client
import java.io.BufferedReader;
import java.io.InputStreamReader;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
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.nio.NioSocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
/**
* netty5的客户端
*
*
*/
public class Client {
public static void main(String[] args) {
//服务类
Bootstrap bootstrap = new Bootstrap();
//worker
EventLoopGroup worker = new NioEventLoopGroup();
try {
//设置线程池
bootstrap.group(worker);
//设置socket工厂、
bootstrap.channel(NioSocketChannel.class);
//设置管道
bootstrap.handler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
ch.pipeline().addLast(new StringDecoder());
ch.pipeline().addLast(new StringEncoder());
ch.pipeline().addLast(new ClientHandler());
}
});
ChannelFuture connect = bootstrap.connect("127.0.0.1", 10101);
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
while(true){
System.out.println("请输入：");
String msg = bufferedReader.readLine();
connect.channel().writeAndFlush(msg);
}
} catch (Exception e) {
e.printStackTrace();
} finally{
worker.shutdownGracefully();
}
}
}
ClientHandler
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
/**
* 客户端消息处理
*
*
*/
public class ClientHandler extends SimpleChannelInboundHandler<String> {
@Override
protected void messageReceived(ChannelHandlerContext ctx, String msg) throws Exception {
System.out.println("客户端收到消息:"+msg);
}
}
多连接客户端
MultClient
其中 synchronized(channel) 可以采用 单任务队列的方式
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
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.nio.NioSocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
/**
* 多连接客户端
*
*
*/
public class MultClient {
/**
* 服务类
*/
private Bootstrap bootstrap = new Bootstrap();
/**
* 会话
*/
private List<Channel> channels = new ArrayList<>();
/**
* 引用计数
*/
private final AtomicInteger index = new AtomicInteger();
/**
* 初始化
* @param count
*/
public void init(int count){
//worker
EventLoopGroup worker = new NioEventLoopGroup();
//设置线程池
bootstrap.group(worker);
//设置socket工厂、
bootstrap.channel(NioSocketChannel.class);
//设置管道
bootstrap.handler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
ch.pipeline().addLast(new StringDecoder());
ch.pipeline().addLast(new StringEncoder());
ch.pipeline().addLast(new ClientHandler());
}
});
for(int i=1; i<=count; i++){
ChannelFuture future = bootstrap.connect("192.168.0.103", 10101);
channels.add(future.channel());
}
}
/**
* 获取会话
* @return
*/
public Channel nextChannel(){
return getFirstActiveChannel(0);
}
private Channel getFirstActiveChannel(int count){
Channel channel = channels.get(Math.abs(index.getAndIncrement() % channels.size()));
if(!channel.isActive()){
//重连
reconnect(channel);
if(count >= channels.size()){
throw new RuntimeException("no can use channel");
}
return getFirstActiveChannel(count + 1);
}
return channel;
}
/**
* 重连
* @param channel
*/
private void reconnect(Channel channel){
synchronized(channel){
if(channels.indexOf(channel) == -1){
return ;
}
Channel newChannel = bootstrap.connect("192.168.0.103", 10101).channel();
channels.set(channels.indexOf(channel), newChannel);
}
}
}
Start
import java.io.BufferedReader;
import java.io.InputStreamReader;
/**
* 启动类
*
*
*/
public class Start {
public static void main(String[] args) {
MultClient client = new MultClient();
client.init(5);
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
while(true){
try {
System.out.println("请输入:");
String msg = bufferedReader.readLine();
client.nextChannel().writeAndFlush(msg);
} catch (Exception e) {
e.printStackTrace();
}
}
}
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版权声明：本文为CSDN博主「chenshiying007」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/qq_27384769/article/details/80674108