你敢信？就是这个Netty的网络框架差点把我整疯了，哭jj
不知道大家对下面的这个图标眼熟不
对，这就是netty，最近差点整疯了我的一个网络框架，下方是官网对他的描述，感兴趣大家可以去官网看一下，这不是今天的重点，接着往下看：
为啥说这玩意快把我整疯了啊，哎，好奇害死猫啊，我这人是对网络一窍不通，所以网络的东西我一般是不去触碰的，但是，最近公司的人以及各大论坛里面，netty这个技术真的是如日中天，我身边的朋友去面试的回来也说这个技术问的有点多啊，我好奇心作怪就想去试一下，然后在网上查找了很多资料和代码实现，我就觉得没啥，于是自己搭建了一下玩玩，比方说下面我要跟大家说的这个重点：netty+springboot实现 长连接 - 心跳 - 自动重连 - 通信
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然后出问题了，我作为程序员的执拗，不能有bug，这就出问题了，我们先来看一下网上的源码
package com.gzky.study;
import com.gzky.study.netty.MsgPckDecode;
import com.gzky.study.netty.MsgPckEncode;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.timeout.IdleStateHandler;
import java.util.Scanner;
/**
* @author biws
* @date 2020/11/20
**/
public class TestFor {
private static NioEventLoopGroup worker = new NioEventLoopGroup();
private static Channel channel;
private static Bootstrap bootstrap;
boolean flag = true;
public static void main(String[] args) {
for (int i = 0; i < 30; i++) {
long start = System.currentTimeMillis();
Scanner sc= new Scanner(System.in);
long end = System.currentTimeMillis();
long l1 = end - start;
long start2 = System.currentTimeMillis();
start();
long end2 = System.currentTimeMillis();
long l2 = end2 - start2;
if (l1 > l2) {
System.out.println("Scanner大，false");
} else {
System.out.println("true--------------");
}
}
}
private static void start() {
bootstrap = new Bootstrap();
bootstrap.group(worker)
.channel(NioSocketChannel.class)
.option(ChannelOption.TCP_NODELAY, true)
.handler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
// TODO Auto-generated method stub
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(new IdleStateHandler(3, 3, 5));
pipeline.addLast(new MsgPckDecode());
pipeline.addLast(new MsgPckEncode());
}
});
doConnect();
}
protected static void doConnect() {
if (channel != null && channel.isActive()) {
return;
}
ChannelFuture connect = bootstrap.connect("127.0.0.1", 8089);
//实现监听通道连接的方法
connect.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture channelFuture) throws Exception {
if (channelFuture.isSuccess()) {
channel = channelFuture.channel();
System.out.println("连接成功");
}
}
});
}
}
好了，到这里，没问题，成功实现，我就觉得这也没啥啊，这不是挺简单的嘛，难道说他们是在面试的时候问道底层源码啊，这玩意整不了 啊，可能这就是命啊，我就没关，让他执行着，喝口饮料休息一下，没想到突然就报错了，然后又好了，emmmm，这不是自己给自己找事啊
通过测试，模拟30次大约有3次失败的样子，回看源码，其实代码中存在的矛盾不难发现，就是Scanner和Channel谁的创建时间更短。可能在他的电脑上没有什么问题，但是在我这里就不行，感觉更像是在赌博，看你运气怎么样，这样那行啊，理工科的男孩子怎么能靠赌博呢？
但是，咋整，我就在这一块就是一个渣渣啊，没办法，最后还是求助了公司的大神，幸好代码量不是特别大，抽了个周末的下午，俺俩一起在原有的代码基础上对客户端进行可以定程度的改造，现在所有的功能都已经实现，下面附上改进后的代码，有需要的朋友可以自己动手实现一下
还是建议实现一下，毕竟可能我这里可以了，但是在你的pc端又会有其他的而不一样的问题，当然了，要是有云服务器测试一下更 不错
一、pom文件
<!-- 解码and编码器 -->
<!-- https://mvnrepository.com/artifact/org.msgpack/msgpack -->
<dependency>
<groupId>org.msgpack</groupId>
<artifactId>msgpack</artifactId>
<version>0.6.12</version>
</dependency>
<!-- 引入netty依赖 -->
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.1.6.Final</version>
</dependency>
二、配置项
package com.gzky.study.netty;
/**
* 配置项
*
*
* @author biws
* @date 2020/11/20
**/
public interface TypeData {
//客户端代码
byte PING = 1;
//服务端代码
byte PONG = 2;
//顾客
byte CUSTOMER = 3;
}
三、消息类型分离器
package com.gzky.study.netty;
import org.msgpack.annotation.Message;
import java.io.Serializable;
/**
* 消息类型分离器
*
*
* @author biws
* @date 2020/11/20
**/
@Message
public class Model implements Serializable {
private static final long serialVersionUID = 1L;
//类型
private int type;
//内容
private String body;
public int getType() {
return type;
}
public void setType(int type) {
this.type = type;
}
public String getBody() {
return body;
}
public void setBody(String body) {
this.body = body;
}
@Override
public String toString() {
return "Model{" +
"type=" + type +
", body='" + body + '\'' +
'}';
}
}
四、编码器
package com.gzky.study.netty;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToByteEncoder;
import org.msgpack.MessagePack;
/**
* 编码器
*
*
* @author biws
* @date 2020/11/20
**/
public class MsgPckEncode extends MessageToByteEncoder<Object> {
@Override
protected void encode(ChannelHandlerContext ctx, Object msg, ByteBuf buf)
throws Exception {
// TODO Auto-generated method stub
MessagePack pack = new MessagePack();
byte[] write = pack.write(msg);
buf.writeBytes(write);
}
}
五、解码器
package com.gzky.study.netty;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToMessageDecoder;
import org.msgpack.MessagePack;
import java.util.List;
/**
* 解码器
*
*
* @author biws
* @date 2020/11/20
**/
public class MsgPckDecode extends MessageToMessageDecoder<ByteBuf> {
@Override
protected void decode(ChannelHandlerContext ctx, ByteBuf msg,
List<Object> out) throws Exception {
final byte[] array;
final int length = msg.readableBytes();
array = new byte[length];
msg.getBytes(msg.readerIndex(), array, 0, length);
MessagePack pack = new MessagePack();
out.add(pack.read(array, Model.class));
}
}
六、公用控制器
package com.gzky.study.netty;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.handler.timeout.IdleStateEvent;
/**
* 公用控制器
*
* @author biws
* @date 2020/11/20
**/
public abstract class Middleware extends ChannelInboundHandlerAdapter {
protected String name;
//记录次数
private int heartbeatCount = 0;
//获取server and client 传入的值
public Middleware(String name) {
this.name = name;
}
/**
*继承ChannelInboundHandlerAdapter实现了channelRead就会监听到通道里面的消息
*/
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg)
throws Exception {
Model m = (Model) msg;
int type = m.getType();
switch (type) {
case 1:
sendPongMsg(ctx);
break;
case 2:
System.out.println(name + " get pong msg from" + ctx.channel().remoteAddress());
break;
case 3:
handlerData(ctx,msg);
break;
default:
break;
}
}
protected abstract void handlerData(ChannelHandlerContext ctx,Object msg);
protected void sendPingMsg(ChannelHandlerContext ctx){
Model model = new Model();
model.setType(TypeData.PING);
ctx.channel().writeAndFlush(model);
heartbeatCount++;
System.out.println(name + " send ping msg to " + ctx.channel().remoteAddress() + "count :" + heartbeatCount);
}
private void sendPongMsg(ChannelHandlerContext ctx) {
Model model = new Model();
model.setType(TypeData.PONG);
ctx.channel().writeAndFlush(model);
heartbeatCount++;
System.out.println(name +" send pong msg to "+ctx.channel().remoteAddress() +" , count :" + heartbeatCount);
}
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt)
throws Exception {
IdleStateEvent stateEvent = (IdleStateEvent) evt;
switch (stateEvent.state()) {
case READER_IDLE:
handlerReaderIdle(ctx);
break;
case WRITER_IDLE:
handlerWriterIdle(ctx);
break;
case ALL_IDLE:
handlerAllIdle(ctx);
break;
default:
break;
}
}
protected void handlerAllIdle(ChannelHandlerContext ctx) {
System.err.println("---ALL_IDLE---");
}
protected void handlerWriterIdle(ChannelHandlerContext ctx) {
System.err.println("---WRITER_IDLE---");
}
protected void handlerReaderIdle(ChannelHandlerContext ctx) {
System.err.println("---READER_IDLE---");
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
// TODO Auto-generated method stub
System.err.println(" ---"+ctx.channel().remoteAddress() +"----- is action" );
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
// TODO Auto-generated method stub
System.err.println(" ---"+ctx.channel().remoteAddress() +"----- is inAction");
}
}
七、客户端
package com.gzky.study.netty;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.timeout.IdleStateHandler;
import java.util.Scanner;
import java.util.concurrent.TimeUnit;
/**
* Client客户端
*
* @author biws
* @date 2020/11/20
**/
public class Client {
private NioEventLoopGroup worker = new NioEventLoopGroup();
private Channel channel;
private Bootstrap bootstrap;
boolean flag = true;
public static void main(String[] args) {
Client client = new Client();
client.start();
client.sendData();
//通信结束，关闭客户端
client.close();
}
private void close() {
channel.close();
worker.shutdownGracefully();
}
private void start() {
bootstrap = new Bootstrap();
bootstrap.group(worker)
.channel(NioSocketChannel.class)
.option(ChannelOption.TCP_NODELAY, true)
.handler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
// TODO Auto-generated method stub
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(new IdleStateHandler(3, 3, 5));
pipeline.addLast(new MsgPckDecode());
pipeline.addLast(new MsgPckEncode());
pipeline.addLast(new Client3Handler(Client.this));
}
});
doConnect();
}
/**
* 连接服务端 and 重连
*/
protected void doConnect() {
if (channel != null && channel.isActive()) {
return;
}
ChannelFuture connect = bootstrap.connect("127.0.0.1", 8089);
//实现监听通道连接的方法
connect.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture channelFuture) throws Exception {
if (channelFuture.isSuccess()) {
channel = channelFuture.channel();
System.out.println("连接成功");
} else {
if (flag) {
System.out.println("每隔2s重连....");
channelFuture.channel().eventLoop().schedule(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
doConnect();
}
}, 2, TimeUnit.SECONDS);
}
}
}
});
}
/**
* 向服务端发送消息
*/
private void sendData() {
//创建连接成功之前停在这里等待
while (channel == null || !channel.isActive()) {
System.out.println("等待连接···");
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("连接成功等待输入：");
flag = true;
Scanner sc = new Scanner(System.in);
while (flag) {
String nextLine = sc.nextLine();
if ("end".equalsIgnoreCase(nextLine)) {
flag = false;
}
Model model = new Model();
model.setType(TypeData.CUSTOMER);
model.setBody(nextLine);
channel.writeAndFlush(model);
}
}
}
八、客户端控制器
package com.gzky.study.netty;
import io.netty.channel.ChannelHandlerContext;
/**
* 客户端控制器
*
* @author biws
* @date 2020/11/20
**/
public class Client3Handler extends Middleware {
private Client client;
public Client3Handler(Client client) {
super("client");
this.client = client;
}
@Override
protected void handlerData(ChannelHandlerContext ctx, Object msg) {
// TODO Auto-generated method stub
Model model = (Model) msg;
System.out.println("client 收到数据： " + model.toString());
}
@Override
protected void handlerAllIdle(ChannelHandlerContext ctx) {
// TODO Auto-generated method stub
super.handlerAllIdle(ctx);
sendPingMsg(ctx);
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
// TODO Auto-generated method stub
super.channelInactive(ctx);
client.doConnect();
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
System.out.println(name + "exception :"+ cause.toString());
}
}
九、服务端
package com.gzky.study.netty;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.timeout.IdleStateHandler;
/**
* 服务端
*
* @author biws
* @date 2020/11/20
**/
public class Server {
public static void main(String[] args) {
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
EventLoopGroup workerGroup = new NioEventLoopGroup(4);
try {
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.localAddress(8089)
.childHandler(new ChannelInitializer<Channel>() {
@Override
protected void initChannel(Channel ch) throws Exception {
// TODO Auto-generated method stub
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(new IdleStateHandler(10,3,10));
pipeline.addLast(new MsgPckDecode());
pipeline.addLast(new MsgPckEncode());
pipeline.addLast(new Server3Handler());
}
});
System.out.println("start server 8089 --");
ChannelFuture sync = serverBootstrap.bind().sync();
sync.channel().closeFuture().sync();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
//优雅的关闭资源
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
十、服务端控制器
package com.gzky.study.netty;
import io.netty.channel.ChannelHandlerContext;
/**
* 服务端控制器
*
* @author biws
* @date 2020/11/20
**/
public class Server3Handler extends Middleware {
public Server3Handler() {
super("server");
// TODO Auto-generated constructor stub
}
@Override
protected void handlerData(ChannelHandlerContext ctx, Object msg) {
// TODO Auto-generated method stub
Model model = (Model) msg;
System.out.println("server 接收数据 ： " + model.toString());
model.setType(TypeData.CUSTOMER);
model.setBody("client你好，server已接收到数据："+model.getBody());
ctx.channel().writeAndFlush(model);
System.out.println("server 发送数据： " + model.toString());
}
@Override
protected void handlerReaderIdle(ChannelHandlerContext ctx) {
// TODO Auto-generated method stub
super.handlerReaderIdle(ctx);
System.err.println(" ---- client "+ ctx.channel().remoteAddress().toString() + " reader timeOut, --- close it");
ctx.close();
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
System.err.println( name +" exception" + cause.toString());
}
}
十一、测试
1、启动服务端
2、启动客户端
3、客户端发消息
在客户端控制台输入：
服务端控制台就可以收到hello，并且回信。
好了，到这里，netty - springboot - 长连接 - 心跳 - 自动重连 - 通信就完成了，不知道你实现了没有，建议你可以先收藏，等有时间了自己实现一下，尤其是刚接触的，觉得写得还不错的，可以转发一下，让更多人看见，谢谢
新的技术学习必定是充满BUG的，但是，解决了就是一片光明，这样一点点的改BUG中，剩下的就是你成长的路径
