1.pipeline调用handler的源码
//pipeline得到双向链表的头,next到尾部,
2.心跳源码 主要分析IdleStateHandler3个定时任务内部类
//考虑了网络传输慢导致出站慢的情况
//超时重新发送,然后关闭
ReadTimeoutHandler(继承IdleStateHandler 直接关闭连接)和WriteTimeoutHandler(继承ChannelOutboundHandlerAdapter 使用定时任务来完成)
//NioEventLoop进行事件循环
@Override
protected void run() {
for (;;) {
try {
switch (selectStrategy.calculateStrategy(selectNowSupplier, hasTasks())) {
case SelectStrategy.CONTINUE:
continue;
case SelectStrategy.SELECT:
select(wakenUp.getAndSet(false));
if (wakenUp.get()) {
selector.wakeup();
}
// fall through
default:
}
cancelledKeys = 0;
needsToSelectAgain = false;
final int ioRatio = this.ioRatio; //默认 50
if (ioRatio == 100) { //如果被占用,就处理事件
try {
processSelectedKeys();
} finally {
// Ensure we always run tasks.
runAllTasks(); //执行任务
}
} else { //如果没有被占用
final long ioStartTime = System.nanoTime();
try {
processSelectedKeys(); //选择一个key
} finally {
// Ensure we always run tasks.
final long ioTime = System.nanoTime() - ioStartTime;
runAllTasks(ioTime * (100 - ioRatio) / ioRatio); //ioRatio默认是50 ,计算出来是1.所以定时任务执行了 ioTime没有响应的时间(妙啊,如果执行1s或者是其他时间那可能还是检测不到心跳)
}
}
} catch (Throwable t) {
handleLoopException(t);
}
// Always handle shutdown even if the loop processing threw an exception.
try {
if (isShuttingDown()) {
closeAll();
if (confirmShutdown()) {
return;
}
}
} catch (Throwable t) {
handleLoopException(t);
}
}
}
//IdleStateHandler
3.eventLoop执行定时任务的源代码(传入并执行队列)
1.select 默认阻塞1秒
4.任务加入异步线程池(处理耗时任务时)(因为执行任务读写 和执行读写后执行Loop任务是同一个线程)
就不会阻塞netty的IO
1.handler加入线程池(自己创建group线程池)
2.context加入线程池
/*
* Copyright 2012 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package source.echo2;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;
import io.netty.util.concurrent.DefaultEventExecutorGroup;
import io.netty.util.concurrent.EventExecutorGroup;
import java.util.concurrent.Callable;
/**
* Handler implementation for the echo server.
*/
@Sharable
public class EchoServerHandler extends ChannelInboundHandlerAdapter {
// group 就是充当业务线程池，可以将任务提交到该线程池
// 这里我们创建了16个线程
static final EventExecutorGroup group = new DefaultEventExecutorGroup(16);
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
System.out.println("EchoServer Handler 的线程是=" + Thread.currentThread().getName());
//按照原来的方法处理耗时任务
//解决方案2 用户程序自定义的普通任务
ctx.channel().eventLoop().execute(new Runnable() {
@Override
public void run() {
try {
Thread.sleep(5 * 1000);
//输出线程名
System.out.println("EchoServerHandler execute 线程是=" + Thread.currentThread().getName());
ctx.writeAndFlush(Unpooled.copiedBuffer("hello, 客户端~(>^ω^<)喵2", CharsetUtil.UTF_8));
} catch (Exception ex) {
System.out.println("发生异常" + ex.getMessage());
}
}
});
ctx.channel().eventLoop().execute(new Runnable() {
@Override
public void run() {
try {
Thread.sleep(5 * 1000);
//输出线程名
System.out.println("EchoServerHandler execute 线程2是=" + Thread.currentThread().getName());
ctx.writeAndFlush(Unpooled.copiedBuffer("hello, 客户端~(>^ω^<)喵2", CharsetUtil.UTF_8));
} catch (Exception ex) {
System.out.println("发生异常" + ex.getMessage());
}
}
});
//方式1
// //将任务提交到 group线程池
// group.submit(new Callable<Object>() {
// @Override
// public Object call() throws Exception {
//
// //接收客户端信息
ByteBuf buf = (ByteBuf) msg;
byte[] bytes = new byte[buf.readableBytes()];
buf.readBytes(bytes);
String body = new String(bytes, "UTF-8");
//休眠10秒
Thread.sleep(10 * 1000);
// System.out.println("group.submit 的 call 线程是=" + Thread.currentThread().getName());
// ctx.writeAndFlush(Unpooled.copiedBuffer("hello, 客户端~(>^ω^<)喵2", CharsetUtil.UTF_8));
// return null;
//
// }
// });
//
// //将任务提交到 group线程池
// group.submit(new Callable<Object>() {
// @Override
// public Object call() throws Exception {
//
// //接收客户端信息
// ByteBuf buf = (ByteBuf) msg;
// byte[] bytes = new byte[buf.readableBytes()];
// buf.readBytes(bytes);
// String body = new String(bytes, "UTF-8");
// //休眠10秒
// Thread.sleep(10 * 1000);
// System.out.println("group.submit 的 call 线程是=" + Thread.currentThread().getName());
// ctx.writeAndFlush(Unpooled.copiedBuffer("hello, 客户端~(>^ω^<)喵2", CharsetUtil.UTF_8));
// return null;
//
// }
// });
//
//
// //将任务提交到 group线程池
// group.submit(new Callable<Object>() {
// @Override
// public Object call() throws Exception {
//
// //接收客户端信息
// ByteBuf buf = (ByteBuf) msg;
// byte[] bytes = new byte[buf.readableBytes()];
// buf.readBytes(bytes);
// String body = new String(bytes, "UTF-8");
// //休眠10秒
// Thread.sleep(10 * 1000);
// System.out.println("group.submit 的 call 线程是=" + Thread.currentThread().getName());
// ctx.writeAndFlush(Unpooled.copiedBuffer("hello, 客户端~(>^ω^<)喵2", CharsetUtil.UTF_8));
// return null;
//
// }
// });
//普通方式
//接收客户端信息
ByteBuf buf = (ByteBuf) msg;
byte[] bytes = new byte[buf.readableBytes()];
buf.readBytes(bytes);
String body = new String(bytes, "UTF-8");
//休眠10秒
Thread.sleep(10 * 1000);
System.out.println("普通调用方式的 线程是=" + Thread.currentThread().getName());
ctx.writeAndFlush(Unpooled.copiedBuffer("hello, 客户端~(>^ω^<)喵2", CharsetUtil.UTF_8));
System.out.println("go on ");
}
@Override
public void channelReadComplete(ChannelHandlerContext ctx) {
ctx.flush();
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
// Close the connection when an exception is raised.
//cause.printStackTrace();
ctx.close();
}
}
5.netty源码
//面试
1.连接 ServerBootstrap空的构造器 作用为初始化类的成员
//启动bind
6.RPC(remote procedure call) call function like local machine
1.usual framework , ali Dubbo google gRPC ,Go rpcx
apache thrift ,spring cloud
pic 17.rpc procedure
- imitate dubbo RPC 通过jdk反射实现
// server handler规定 msg开头是规定的字符串(或者协议)
msg.toString().startsWith(“helloService#hello”)
//callable可以在服务器和客户端之间使用,wait()然后notify() (在同一机器)
//read调用只一次,然后调用call(netty的pipeline自动调用)
//server和client,只需按照需要的名字来调用
//下面是客户端传递参数给服务端,然后服务端调用被代理的实现的接口
//创建消费者,调用远程服务
public class ClientBootstrap {
//这里定义协议头(调用的方法名)
public static final String providerName = "HelloService#hello#";
public static void main(String[] args) throws Exception{
//创建一个消费者
NettyClient customer = new NettyClient();
//创建代理对象
HelloService service = (HelloService) customer.getBean(HelloService.class, providerName);
for (;;) {
Thread.sleep(2 * 1000);
//通过代理对象调用服务提供者的方法(服务)
String res = service.hello("你好 dubbo~");
System.out.println("调用的结果 res= " + res);
}
}
}
//创建客户端创建代理对象,和初始化客户端添加handler
public class NettyClient {
//创建线程池
private static ExecutorService executor = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
private static NettyClientHandler client;
private int count = 0;
//编写方法使用代理模式，获取一个代理对象
public Object getBean(final Class<?> serivceClass, final String providerName) {
return Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(),
new Class<?>[]{serivceClass}, (proxy, method, args) -> {
System.out.println("(proxy, method, args) 进入...." + (++count) + " 次");
//{} 部分的代码，客户端每调用一次 hello, 就会进入到该代码
if (client == null) {
initClient();
}
//设置要发给服务器端的信息
//providerName 协议头 args[0] 就是客户端调用api hello(???), 参数
client.setPara(providerName + args[0]);
return executor.submit(client).get();
});
}
//初始化客户端
private static void initClient() {
client = new NettyClientHandler();
//创建EventLoopGroup
NioEventLoopGroup group = new NioEventLoopGroup();
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(group)
.channel(NioSocketChannel.class)
.option(ChannelOption.TCP_NODELAY, true)
.handler(
new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(new StringDecoder());
pipeline.addLast(new StringEncoder());
pipeline.addLast(client);
}
}
);
try {
bootstrap.connect("127.0.0.1", 7000).sync();
} catch (Exception e) {
e.printStackTrace();
}
}
}
//客户端handler,处理来自服务器的请求,服务器有数据通知线程,没有就等待
public class NettyClientHandler extends ChannelInboundHandlerAdapter implements Callable {
private ChannelHandlerContext context;//上下文
private String result; //返回的结果
private String para; //客户端调用方法时，传入的参数
//与服务器的连接创建后，就会被调用, 这个方法是第一个被调用(1)
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
System.out.println(" channelActive 被调用 ");
context = ctx; //因为我们在其它方法会使用到 ctx
}
//收到服务器的数据后，调用方法 (4)
//
@Override
public synchronized void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
System.out.println(" channelRead 被调用 ");
result = msg.toString();
notify(); //服务器返回数据,唤醒等待的线程
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
ctx.close();
}
//被代理对象调用, 发送数据给服务器，-> wait -> 等待被唤醒(channelRead) -> 返回结果 (3)-》5
@Override
public synchronized Object call() throws Exception {
System.out.println(" call1 被调用 ");
context.writeAndFlush(para); //这里的context是client自己的,
//进行wait
wait(); //等待channelRead 方法获取到服务器的结果后，唤醒
System.out.println(" call2 被调用 ");
return result; //服务方返回的结果
}
//(2)
void setPara(String para) {
System.out.println(" setPara ");
this.para = para;
}
}
//创建服务器端,添加服务器handler文章来源：https://www.toymoban.com/news/detail-628169.html
public class NettyServer {
public static void startServer(String hostName, int port) {
startServer0(hostName,port);
}
//编写一个方法，完成对NettyServer的初始化和启动
private static void startServer0(String hostname, int port) {
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup,workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(new StringDecoder());
pipeline.addLast(new StringEncoder());
pipeline.addLast(new NettyServerHandler()); //业务处理器
}
}
);
ChannelFuture channelFuture = serverBootstrap.bind(hostname, port).sync();
System.out.println("服务提供方开始提供服务~~");
channelFuture.channel().closeFuture().sync();
}catch (Exception e) {
e.printStackTrace();
}
finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
public static void main(String[] args) {
//代码代填..
NettyServer.startServer("127.0.0.1", 7000);
}
}
//服务器handler,如果接收到客户端的请求,得到字符,传入参数调用实现类方法
public class NettyServerHandler extends ChannelInboundHandlerAdapter {
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
//获取客户端发送的消息，并调用服务
System.out.println("msg=" + msg);
//客户端在调用服务器的api 时，我们需要定义一个协议
//比如我们要求 每次发消息是都必须以某个字符串开头 "HelloService#hello#你好"
if(msg.toString().startsWith(ClientBootstrap.providerName)) {
msg.toString().lastIndexOf("#")
String substring = msg.toString().substring(msg.toString().lastIndexOf("#") + 1);
String result = new HelloServiceImpl().hello(substring);
ctx.writeAndFlush(result); //向客户端写回返回的结果
}
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
ctx.close();
}
}
//接口(客户端需要,使用jdk代理可以代理接口,使用cglib可以直接代理类)
//这个是接口，是服务提供方和 服务消费方都需要文章来源地址https://www.toymoban.com/news/detail-628169.html
public interface HelloService {
String hello(String mes);
}
//实现类
public class HelloServiceImpl implements HelloService {
private static int count = 0;
//当有消费方调用该方法时， 就返回一个结果
@Override
public String hello(String mes) {
System.out.println("收到客户端消息=" + mes);
//根据mes 返回不同的结果
if(mes != null) {
return "你好客户端, 我已经收到你的消息 [" + mes + "] 第" + (++count) + " 次";
} else {
return "你好客户端, 我已经收到你的消息 ";
}
}
}
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