Java handwritten RPC from scratch (02)-netty4 to achieve client and server

illustrate

The socket-based implementation of the previous code is very simple, but for actual production, netty is generally used.

As for the advantages of netty, you can refer to:

Why choose netty?

http://houbb.github.io/2019/05/10/netty-definitive-gudie-04-why-netty

Code

Introduced by maven

<dependency>
    <groupId>io.netty</groupId>
    <artifactId>netty-all</artifactId>
    <version>${netty.version}</version>
</dependency>

Introduce the maven package corresponding to netty, here is 4.1.17.Final.

Server code implementation

Netty's server startup code is relatively fixed.

package com.github.houbb.rpc.server.core;

import com.github.houbb.log.integration.core.Log;
import com.github.houbb.log.integration.core.LogFactory;
import com.github.houbb.rpc.server.constant.RpcServerConst;
import com.github.houbb.rpc.server.handler.RpcServerHandler;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;

/**
 * rpc 服务端
 * @author binbin.hou
 * @since 0.0.1
 */
public class RpcServer extends Thread {

    private static final Log log = LogFactory.getLog(RpcServer.class);

    /**
     * 端口号
     */
    private final int port;

    public RpcServer() {
        this.port = RpcServerConst.DEFAULT_PORT;
    }

    public RpcServer(int port) {
        this.port = port;
    }

    @Override
    public void run() {
        // 启动服务端
        log.info("RPC 服务开始启动服务端");

        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.group(workerGroup, bossGroup)
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new ChannelInitializer<Channel>() {
                        @Override
                        protected void initChannel(Channel ch) throws Exception {
                            ch.pipeline().addLast(new RpcServerHandler());
                        }
                    })
                    // 这个参数影响的是还没有被accept 取出的连接
                    .option(ChannelOption.SO_BACKLOG, 128)
                    // 这个参数只是过一段时间内客户端没有响应，服务端会发送一个 ack 包，以判断客户端是否还活着。
                    .childOption(ChannelOption.SO_KEEPALIVE, true);

            // 绑定端口，开始接收进来的链接
            ChannelFuture channelFuture = serverBootstrap.bind(port).syncUninterruptibly();
            log.info("RPC 服务端启动完成，监听【" + port + "】端口");

            channelFuture.channel().closeFuture().syncUninterruptibly();
            log.info("RPC 服务端关闭完成");
        } catch (Exception e) {
            log.error("RPC 服务异常", e);
        } finally {
            workerGroup.shutdownGracefully();
            bossGroup.shutdownGracefully();
        }
    }

}

For simplicity, the server start port number is fixed, and the contents of the RpcServerConst constant class are as follows:

public final class RpcServerConst {

    private RpcServerConst(){}

    /**
     * 默认端口
     * @since 0.0.1
     */
    public static final int DEFAULT_PORT = 9627;

}

RpcServerHandler

Of course, there is a more core class is RpcServerHandler

public class RpcServerHandler extends SimpleChannelInboundHandler {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
        // do nothing now
    }
}

The current implementation is empty, and the corresponding log output and logic processing can be added later.

test

The code to start the test is very simple:

/**
 * 服务启动代码测试
 * @param args 参数
 */
public static void main(String[] args) {
    new RpcServer().start();
}

illustrate

We have implemented the server-side implementation above. In this section, let's take a look at the client-side code implementation.

Code

RpcClient

/*
 * Copyright (c)  2019. houbinbin Inc.
 * rpc All rights reserved.
 */

package com.github.houbb.rpc.client.core;

import com.github.houbb.log.integration.core.Log;
import com.github.houbb.log.integration.core.LogFactory;
import com.github.houbb.rpc.client.handler.RpcClientHandler;

import io.netty.bootstrap.Bootstrap;
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.NioSocketChannel;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;

/**
 * <p> rpc 客户端 </p>
 *
 * <pre> Created: 2019/10/16 11:21 下午  </pre>
 * <pre> Project: rpc  </pre>
 *
 * @author houbinbin
 * @since 0.0.2
 */
public class RpcClient extends Thread {

    private static final Log log = LogFactory.getLog(RpcClient.class);

    /**
     * 监听端口号
     */
    private final int port;

    public RpcClient(int port) {
        this.port = port;
    }

    public RpcClient() {
        this(9527);
    }

    @Override
    public void run() {
        // 启动服务端
        log.info("RPC 服务开始启动客户端");

        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            Bootstrap bootstrap = new Bootstrap();
            ChannelFuture channelFuture = bootstrap.group(workerGroup)
                    .channel(NioSocketChannel.class)
                    .option(ChannelOption.SO_KEEPALIVE, true)
                    .handler(new ChannelInitializer<Channel>(){
                        @Override
                        protected void initChannel(Channel ch) throws Exception {
                            ch.pipeline()
                                    .addLast(new LoggingHandler(LogLevel.INFO))
                                    .addLast(new RpcClientHandler());
                        }
                    })
                    .connect("localhost", port)
                    .syncUninterruptibly();

            log.info("RPC 服务启动客户端完成，监听端口：" + port);
            channelFuture.channel().closeFuture().syncUninterruptibly();
            log.info("RPC 服务开始客户端已关闭");
        } catch (Exception e) {
            log.error("RPC 客户端遇到异常", e);
        } finally {
            workerGroup.shutdownGracefully();
        }
    }

}

.connect("localhost", port) declares the server that the client needs to connect to, and the port here is the same as that of the server.

RpcClientHandler

The client-side processing class is also relatively simple, leave it blank for now.

/*
 * Copyright (c)  2019. houbinbin Inc.
 * rpc All rights reserved.
 */

package com.github.houbb.rpc.client.handler;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;

/**
 * <p> 客户端处理类 </p>
 *
 * <pre> Created: 2019/10/16 11:30 下午  </pre>
 * <pre> Project: rpc  </pre>
 *
 * @author houbinbin
 * @since 0.0.2
 */
public class RpcClientHandler extends SimpleChannelInboundHandler {

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
        // do nothing.
    }

}

Start the test

Server

Start the server first.

Client

Then start the client to connect to the server, the implementation is as follows:

/**
 * 服务启动代码测试
 * @param args 参数
 */
public static void main(String[] args) {
    new RpcClient().start();
}

summary

In order to facilitate everyone to learn, the above source code has been open source:

https://github.com/houbb/rpc

I am an old horse, and I look forward to seeing you again next time.