netty入门教程话题之心跳
1、学习idleStateHandler
用来检测会话状态
2、心跳其实就是一个普通的请求，特点数据简单，业务也简单
心跳对于服务端来说，定时清除闲置会话inactive(netty5) channelclose(netty3)
心跳对客户端来说，用来检测会话是否断开，是否重连！ 用来检测网络延时！
1.netty3的心跳实现。
HelloHandlerpackage com.cxb.netty3.heart;
import org.jboss.netty.channel.ChannelEvent;
import org.jboss.netty.channel.ChannelFuture;
import org.jboss.netty.channel.ChannelFutureListener;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelHandler;
import org.jboss.netty.handler.timeout.IdleState;
import org.jboss.netty.handler.timeout.IdleStateEvent;
public class HelloHandler extends SimpleChannelHandler {
@Override
public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
System.out.println(e.getMessage());
}
@Override
public void handleUpstream(final ChannelHandlerContext ctx, ChannelEvent e) throws Exception {
if (e instanceof IdleStateEvent) {
if(((IdleStateEvent)e).getState() == IdleState.ALL_IDLE){
System.out.println("踢玩家下线");
//关闭会话,踢玩家下线
ChannelFuture write = ctx.getChannel().write("time out, you will close");
write.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
ctx.getChannel().close();
}
});
}
} else {
super.handleUpstream(ctx, e);
}
}
}
Serverpackage com.cxb.netty3.heart;
import java.net.InetSocketAddress;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import org.jboss.netty.bootstrap.ServerBootstrap;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelPipelineFactory;
import org.jboss.netty.channel.Channels;
import org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory;
import org.jboss.netty.handler.codec.string.StringDecoder;
import org.jboss.netty.handler.codec.string.StringEncoder;
import org.jboss.netty.handler.timeout.IdleStateHandler;
import org.jboss.netty.util.HashedWheelTimer;
/**
* netty服务端入门
*/
public class Server {
public static void main(String[] args) {
//服务类
ServerBootstrap bootstrap = new ServerBootstrap();
//boss线程监听端口，worker线程负责数据读写
ExecutorService boss = Executors.newCachedThreadPool();
ExecutorService worker = Executors.newCachedThreadPool();
//设置niosocket工厂
bootstrap.setFactory(new NioServerSocketChannelFactory(boss, worker));
final HashedWheelTimer hashedWheelTimer = new HashedWheelTimer();
//设置管道的工厂
bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
@Override
public ChannelPipeline getPipeline() throws Exception {
ChannelPipeline pipeline = Channels.pipeline();
// 这里设置超时时间10s，期间内没有操作，则会关闭
pipeline.addLast("idle", new IdleStateHandler(hashedWheelTimer, 5, 5, 10));
pipeline.addLast("decoder", new StringDecoder());
pipeline.addLast("encoder", new StringEncoder());
pipeline.addLast("helloHandler", new HelloHandler());
return pipeline;
}
});
bootstrap.bind(new InetSocketAddress(8007));
System.out.println("start!");
}
}
测试，使用telnet连接测试，等待10s，如果没有操作，则关闭连接。
发送了消息之后，10内不超过也会断开连接。
2.netty5的心跳实现
ServerHandlerpackage com.cxb.netty5.heart;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.timeout.IdleState;
import io.netty.handler.timeout.IdleStateEvent;
/**
* 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");
}
@Override
public void userEventTriggered(final ChannelHandlerContext ctx, Object evt) throws Exception {
if(evt instanceof IdleStateEvent){
IdleStateEvent event = (IdleStateEvent)evt;
if(event.state() == IdleState.ALL_IDLE){
//清除超时会话
ChannelFuture writeAndFlush = ctx.writeAndFlush("time is gone, you will close");
writeAndFlush.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) throws Exception {
ctx.channel().close();
}
});
}
}else{
super.userEventTriggered(ctx, evt);
}
}
/**
* 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();
}
}
Serverpackage com.cxb.netty5.heart;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.handler.timeout.IdleStateHandler;
/**
* 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 IdleStateHandler(5, 5, 10));
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(8008);
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();
}
}
}
测试步骤跟netty3一样的流程。
代码下载