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Netty入門例項列子

阿新 • • 發佈：2020-09-21

maven專案Pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version> <!-- 我這裡用的1.5.9 -->
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <groupId>NettyText</groupId>
    <artifactId>NettyText1</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <dependency>
            <groupId>io.dropwizard.metrics</groupId>
            <artifactId>metrics-core</artifactId>
            <version>4.1.1</version>
        </dependency>
        <dependency>
            <groupId>io.dropwizard.metrics</groupId>
            <artifactId>metrics-jmx</artifactId>
            <version>4.1.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
        </dependency>
        <!--netty依賴-->
        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version> 4.1.41.Final</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>7</source>
                    <target>7</target>
                </configuration>
            </plugin>
        </plugins>
    </build>


</project>

Netty Server服務端


package com.netty;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpObject;

import io.netty.handler.codec.LineBasedFrameDecoder;
import io.netty.handler.codec.string.StringDecoder;
import java.net.InetSocketAddress;

public class NettyServer {

public static void main(String[] arg) throws InterruptedException
{
//定義兩個事件組
//接收連線但是不對連線做任何處理會把事情交給workerGroup去做
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {

//啟動服務
ServerBootstrap serverBootStrap = new ServerBootstrap();
serverBootStrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.option(ChannelOption.SO_BACKLOG, 1024)
.childHandler(new ChildChannelHandler());
//繫結埠
ChannelFuture f = serverBootStrap.bind(8080).sync();
//等待服務端 監聽埠關閉
f.channel().closeFuture().sync();
}catch (Exception ex)
{

}
finally {
//優雅的關閉Netty
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}

//ChildChannelHandler加到了channel的pipeline裡面

private static class ChildChannelHandler extends ChannelInitializer<SocketChannel>
{

@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
// LineBasedFrameDecoder 新增行解析器，新增stringDecoder
//StringDecoder作用就是將接收到的訊息轉為字串
socketChannel.pipeline().addLast(new LineBasedFrameDecoder(1024));
socketChannel.pipeline().addLast(new StringDecoder());

socketChannel.pipeline().addLast("TestHttpServerHandler",new TestHttpServerHandler());
}
}

}

TestHttpServerHandler（時間伺服器服務端）加到了channel的pipeline裡面

TestHttpServerHandler 繼承自ChannelInboundHandlerAdapter

package com.netty;

import com.fasterxml.jackson.core.io.CharTypes;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.*;
import io.netty.util.CharsetUtil;

import java.nio.ByteBuffer;
import java.util.Date;



public class TestHttpServerHandler extends ChannelInboundHandlerAdapter {

    private final static String SEPARATOR = "\r\n";

    private static int counter = 0;

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        String body = (String) msg;
        System.out.println(body + ", current counter is " + ++counter);

        String currentTime = "QUERY TIME ORDER".equals(body) ?
                new Date().toString() : "BAD ORDER";
        ByteBuf buf = Unpooled.copiedBuffer((currentTime + SEPARATOR).getBytes());
        ctx.write(buf);
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        ctx.close();
    }
}

Netty Client客戶端

package com.netty;
import io.netty.bootstrap.Bootstrap;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.http.HttpObject;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.codec.LineBasedFrameDecoder;
import io.netty.handler.codec.http.HttpObject;
import io.netty.handler.codec.string.StringDecoder;
public class NettyClient {



    public static  void main(String[] arg)
    {
        EventLoopGroup group = new NioEventLoopGroup();
        try{

            Bootstrap bootstrap = new Bootstrap();
            bootstrap.group(group)
                    .channel(NioSocketChannel.class)
                    .option(ChannelOption.TCP_NODELAY,true)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline pipeline = ch.pipeline();
                            // LineBasedFrameDecoder 新增行解析器，新增stringDecoder
                            //StringDecoder作用就是將接收到的訊息轉為字串
                            pipeline.addLast(new LineBasedFrameDecoder(1024));
                            pipeline.addLast(new StringDecoder());
                            pipeline.addLast(new LoggingHandler(LogLevel.INFO))
                                    .addLast(new TimeClientHandler());

                        }
                    });

            //start the client
            ChannelFuture future = bootstrap.connect("127.0.0.1", 8080).sync();
            //wait until the connection is closed
            future.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            //shut down the event loop to terminate all threads
            group.shutdownGracefully();
        }

    }
}

客戶端的訊息處理器：

package com.netty;


import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import lombok.extern.slf4j.Slf4j;

@Slf4j
public class TimeClientHandler extends ChannelInboundHandlerAdapter {
    private static int counter = 0;

    private byte[] req;

    private final static String SEPARATOR = "\r\n";

    public TimeClientHandler() {
        req = ("QUERY TIME ORDER" + SEPARATOR).getBytes();
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        ByteBuf message = null;

           for (int i = 0; i < 10; i++) {
                message = Unpooled.buffer(req.length);
                message.writeBytes(req);
                ctx.writeAndFlush(message);
         }


    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        String body = (String) msg;
        System.out.println("當前時間: " + body + ", current counter is " + ++counter);

    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        log.info("遇到錯誤");
        ctx.close();
    }
}

執行結果：

10:47:15.576 [nioEventLoopGroup-2-1] INFO io.netty.handler.logging.LoggingHandler - [id: 0xe5792ee2, L:/127.0.0.1:13998 - R:/127.0.0.1:8080] WRITE: 18B
+-------------------------------------------------+
| 0 1 2 3 4 5 6 7 8 9 a b c d e f |
+--------+-------------------------------------------------+----------------+
|00000000| 51 55 45 52 59 20 54 49 4d 45 20 4f 52 44 45 52 |QUERY TIME ORDER|
|00000010| 0d 0a |.. |
+--------+-------------------------------------------------+----------------+
10:47:15.577 [nioEventLoopGroup-2-1] INFO io.netty.handler.logging.LoggingHandler - [id: 0xe5792ee2, L:/127.0.0.1:13998 - R:/127.0.0.1:8080] FLUSH
10:47:15.591 [nioEventLoopGroup-2-1] INFO io.netty.handler.logging.LoggingHandler - [id: 0xe5792ee2, L:/127.0.0.1:13998 - R:/127.0.0.1:8080] READ: Tue Sep 08 10:47:15 CST 2020
當前時間: Tue Sep 08 10:47:15 CST 2020, current counter is 1
10:47:15.591 [nioEventLoopGroup-2-1] INFO io.netty.handler.logging.LoggingHandler - [id: 0xe5792ee2, L:/127.0.0.1:13998 - R:/127.0.0.1:8080] READ: Tue Sep 08 10:47:15 CST 2020
當前時間: Tue Sep 08 10:47:15 CST 2020, current counter is 2
10:47:15.591 [nioEventLoopGroup-2-1] INFO io.netty.handler.logging.LoggingHandler - [id: 0xe5792ee2, L:/127.0.0.1:13998 - R:/127.0.0.1:8080] READ: Tue Sep 08 10:47:15 CST 2020
當前時間: Tue Sep 08 10:47:15 CST 2020, current counter is 3
10:47:15.592 [nioEventLoopGroup-2-1] INFO io.netty.handler.logging.LoggingHandler - [id: 0xe5792ee2, L:/127.0.0.1:13998 - R:/127.0.0.1:8080] READ: Tue Sep 08 10:47:15 CST 2020
當前時間: Tue Sep 08 10:47:15 CST 2020, current counter is 4
10:47:15.592 [nioEventLoopGroup-2-1] INFO io.netty.handler.logging.LoggingHandler - [id: 0xe5792ee2, L:/127.0.0.1:13998 - R:/127.0.0.1:8080] READ: Tue Sep 08 10:47:15 CST 2020
當前時間: Tue Sep 08 10:47:15 CST 2020, current counter is 5
10:47:15.592 [nioEventLoopGroup-2-1] INFO io.netty.handler.logging.LoggingHandler - [id: 0xe5792ee2, L:/127.0.0.1:13998 - R:/127.0.0.1:8080] READ: Tue Sep 08 10:47:15 CST 2020
當前時間: Tue Sep 08 10:47:15 CST 2020, current counter is 6
10:47:15.592 [nioEventLoopGroup-2-1] INFO io.netty.handler.logging.LoggingHandler - [id: 0xe5792ee2, L:/127.0.0.1:13998 - R:/127.0.0.1:8080] READ: Tue Sep 08 10:47:15 CST 2020
當前時間: Tue Sep 08 10:47:15 CST 2020, current counter is 7
10:47:15.593 [nioEventLoopGroup-2-1] INFO io.netty.handler.logging.LoggingHandler - [id: 0xe5792ee2, L:/127.0.0.1:13998 - R:/127.0.0.1:8080] READ: Tue Sep 08 10:47:15 CST 2020
當前時間: Tue Sep 08 10:47:15 CST 2020, current counter is 8
10:47:15.593 [nioEventLoopGroup-2-1] INFO io.netty.handler.logging.LoggingHandler - [id: 0xe5792ee2, L:/127.0.0.1:13998 - R:/127.0.0.1:8080] READ: Tue Sep 08 10:47:15 CST 2020
當前時間: Tue Sep 08 10:47:15 CST 2020, current counter is 9
10:47:15.594 [nioEventLoopGroup-2-1] INFO io.netty.handler.logging.LoggingHandler - [id: 0xe5792ee2, L:/127.0.0.1:13998 - R:/127.0.0.1:8080] READ: Tue Sep 08 10:47:15 CST 2020
當前時間: Tue Sep 08 10:47:15 CST 2020, current counter is 10
10:47:15.594 [nioEventLoopGroup-2-1] INFO io.netty.handler.logging.LoggingHandler - [id: 0xe5792ee2, L:/127.0.0.1:13998 - R:/127.0.0.1:8080] READ COMPLETE

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