说明

java 从零开始手写 RPC (01) 基于 websocket 实现

java 从零开始手写 RPC (02)-netty4 实现客户端和服务端

写完了客户端和服务端，那么如何实现客户端和服务端的调用呢？

下面就让我们一起来看一下。

接口定义计算方法

package com.github.houbb.rpc.common.service;import com.github.houbb.rpc.common.model.CalculateRequest;import com.github.houbb.rpc.common.model.CalculateResponse;/** * <p> 计算服务接口 </p> * * <pre> Created: 2018/8/24 下午4:47  </pre> * <pre> Project: fake  </pre> * * @author houbinbin * @since 0.0.1 */public interface Calculator {    /**     * 计算加法     * @param request 请求入参     * @return 返回结果     */    CalculateResponse sum(final CalculateRequest request);}

pojo

对应的参数对象：

•CalculateRequest

package com.github.houbb.rpc.common.model;import java.io.Serializable;/** * <p> 请求入参 </p> * * <pre> Created: 2018/8/24 下午5:05  </pre> * <pre> Project: fake  </pre> * * @author houbinbin * @since 0.0.3 */public class CalculateRequest implements Serializable {    private static final long serialVersionUID = 6420751004355300996L;    /**     * 参数一     */    private int one;    /**     * 参数二     */    private int two;    public CalculateRequest() {    }    public CalculateRequest(int one, int two) {        this.one = one;        this.two = two;    }    //getter setter toString}

•CalculateResponse

package com.github.houbb.rpc.common.model;import java.io.Serializable;/** * <p> 请求入参 </p> * * <pre> Created: 2018/8/24 下午5:05  </pre> * <pre> Project: fake  </pre> * * @author houbinbin * @since 0.0.3 */public class CalculateResponse implements Serializable {    private static final long serialVersionUID = -1972014736222511341L;    /**     * 是否成功     */   private boolean success;    /**     * 二者的和     */   private int sum;    public CalculateResponse() {    }    public CalculateResponse(boolean success, int sum) {        this.success = success;        this.sum = sum;    }    //getter setter toString}

客户端核心部分

RpcClient 需要添加对应的 Handler，调整如下：

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 CalculateRequestEncoder())                        .addLast(new CalculateResponseDecoder())                        .addLast(new RpcClientHandler());            }        })        .connect(RpcConstant.ADDRESS, port)        .syncUninterruptibly();

netty 中的 handler 泳道设计的非常优雅，让我们的代码可以非常灵活地进行拓展。

接下来我们看一下对应的实现。

RpcClientHandler

package com.github.houbb.rpc.client.handler;import com.github.houbb.log.integration.core.Log;import com.github.houbb.log.integration.core.LogFactory;import com.github.houbb.rpc.client.core.RpcClient;import com.github.houbb.rpc.common.model.CalculateRequest;import com.github.houbb.rpc.common.model.CalculateResponse;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 {    private static final Log log = LogFactory.getLog(RpcClient.class);    @Override    public void channelActive(ChannelHandlerContext ctx) throws Exception {        CalculateRequest request = new CalculateRequest(1, 2);        ctx.writeAndFlush(request);        log.info("[Client] request is :{}", request);    }    @Override    protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {        CalculateResponse response = (CalculateResponse)msg;        log.info("[Client] response is :{}", response);    }}

这里比较简单，channelActive 中我们直接发起调用，入参的对象为了简单，此处固定写死。

channelRead0 中监听服务端的相应结果，并做日志输出。

CalculateRequestEncoder

请求参数是一个对象，netty 是无法直接传输的，我们将其转换为基本对象：

package com.github.houbb.rpc.client.encoder;import com.github.houbb.rpc.common.model.CalculateRequest;import io.netty.buffer.ByteBuf;import io.netty.channel.ChannelHandlerContext;import io.netty.handler.codec.MessageToByteEncoder;/** * @author binbin.hou * @since 0.0.3 */public class CalculateRequestEncoder extends MessageToByteEncoder<CalculateRequest> {    @Override    protected void encode(ChannelHandlerContext ctx, CalculateRequest msg, ByteBuf out) throws Exception {        int one = msg.getOne();        int two = msg.getTwo();        out.writeInt(one);        out.writeInt(two);    }}

CalculateResponseDecoder

针对服务端的响应，也是同理。

我们需要把基本的类型，封装转换为我们需要的对象。

package com.github.houbb.rpc.client.decoder;import com.github.houbb.rpc.common.model.CalculateResponse;import io.netty.buffer.ByteBuf;import io.netty.channel.ChannelHandlerContext;import io.netty.handler.codec.ByteToMessageDecoder;import java.util.List;/** * 响应参数解码 * @author binbin.hou * @since 0.0.3 */public class CalculateResponseDecoder extends ByteToMessageDecoder {    @Override    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {        boolean success = in.readBoolean();        int sum = in.readInt();        CalculateResponse response = new CalculateResponse(success, sum);        out.add(response);    }}

服务端设置处理类

RpcServer 中的处理类要稍微调整一下，其他的保持不变。

ServerBootstrap serverBootstrap = new ServerBootstrap();serverBootstrap.group(workerGroup, bossGroup)        .channel(NioServerSocketChannel.class)        // 打印日志        .handler(new LoggingHandler(LogLevel.INFO))        .childHandler(new ChannelInitializer<Channel>() {            @Override            protected void initChannel(Channel ch) throws Exception {                ch.pipeline()                        .addLast(new CalculateRequestDecoder())                        .addLast(new CalculateResponseEncoder())                        .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);

RpcServerHandler

一开始这里是空实现，我们来添加一下对应的实现。

package com.github.houbb.rpc.server.handler;import com.github.houbb.log.integration.core.Log;import com.github.houbb.log.integration.core.LogFactory;import com.github.houbb.rpc.common.model.CalculateRequest;import com.github.houbb.rpc.common.model.CalculateResponse;import com.github.houbb.rpc.common.service.Calculator;import com.github.houbb.rpc.server.service.CalculatorService;import io.netty.channel.ChannelHandlerContext;import io.netty.channel.SimpleChannelInboundHandler;/** * @author binbin.hou * @since 0.0.1 */public class RpcServerHandler extends SimpleChannelInboundHandler {    private static final Log log = LogFactory.getLog(RpcServerHandler.class);    @Override    public void channelActive(ChannelHandlerContext ctx) throws Exception {        final String id = ctx.channel().id().asLongText();        log.info("[Server] channel {} connected " + id);    }    @Override    protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {        final String id = ctx.channel().id().asLongText();        CalculateRequest request = (CalculateRequest)msg;        log.info("[Server] receive channel {} request: {} from ", id, request);        Calculator calculator = new CalculatorService();        CalculateResponse response = calculator.sum(request);        // 回写到 client 端        ctx.writeAndFlush(response);        log.info("[Server] channel {} response {}", id, response);    }}

读取到客户端的访问之后，我们获取到计算的入参 CalculateRequest，然后调用 sum 方法，获取到对应的 CalculateResponse，将结果通知客户端。

CalculateRequestDecoder

这里和客户端是一一对应的，我们首先把 netty 传递的基本类型转换为 CalculateRequest 对象。

package com.github.houbb.rpc.server.decoder;import com.github.houbb.rpc.common.model.CalculateRequest;import io.netty.buffer.ByteBuf;import io.netty.channel.ChannelHandlerContext;import io.netty.handler.codec.ByteToMessageDecoder;import java.util.List;/** * 请求参数解码 * @author binbin.hou * @since 0.0.3 */public class CalculateRequestDecoder extends ByteToMessageDecoder {    @Override    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {        int one = in.readInt();        int two = in.readInt();        CalculateRequest request = new CalculateRequest(one, two);        out.add(request);    }}

CalculateResponseEncoder

这里和客户端类似，我们需要把 response 转换为基本类型进行网络传输。

package com.github.houbb.rpc.server.encoder;import com.github.houbb.rpc.common.model.CalculateResponse;import io.netty.buffer.ByteBuf;import io.netty.channel.ChannelHandlerContext;import io.netty.handler.codec.MessageToByteEncoder;/** * @author binbin.hou * @since 0.0.3 */public class CalculateResponseEncoder extends MessageToByteEncoder<CalculateResponse> {    @Override    protected void encode(ChannelHandlerContext ctx, CalculateResponse msg, ByteBuf out) throws Exception {        boolean success = msg.isSuccess();        int result = msg.getSum();        out.writeBoolean(success);        out.writeInt(result);    }}

CalculatorService

服务端对应的实现类。

public class CalculatorService implements Calculator {    @Override    public CalculateResponse sum(CalculateRequest request) {        int sum = request.getOne()+request.getTwo();        return new CalculateResponse(true, sum);    }}

测试服务端

启动服务端：

new RpcServer().start();

服务端启动日志：

[DEBUG] [2021-10-05 11:53:11.795] [main] [c.g.h.l.i.c.LogFactory.setImplementation] - Logging initialized using 'class com.github.houbb.log.integration.adaptors.stdout.StdOutExImpl' adapter.[INFO] [2021-10-05 11:53:11.807] [Thread-0] [c.g.h.r.s.c.RpcServer.run] - RPC 服务开始启动服务端十月 05, 2021 11:53:13 上午 io.netty.handler.logging.LoggingHandler channelRegistered信息: [id: 0xd399474f] REGISTERED十月 05, 2021 11:53:13 上午 io.netty.handler.logging.LoggingHandler bind信息: [id: 0xd399474f] BIND: 0.0.0.0/0.0.0.0:9527十月 05, 2021 11:53:13 上午 io.netty.handler.logging.LoggingHandler channelActive信息: [id: 0xd399474f, L:/0:0:0:0:0:0:0:0:9527] ACTIVE[INFO] [2021-10-05 11:53:13.101] [Thread-0] [c.g.h.r.s.c.RpcServer.run] - RPC 服务端启动完成，监听【9527】端口

客户端

启动客户端：

new RpcClient().start();

日志如下：

[DEBUG] [2021-10-05 11:54:12.158] [main] [c.g.h.l.i.c.LogFactory.setImplementation] - Logging initialized using 'class com.github.houbb.log.integration.adaptors.stdout.StdOutExImpl' adapter.[INFO] [2021-10-05 11:54:12.164] [Thread-0] [c.g.h.r.c.c.RpcClient.run] - RPC 服务开始启动客户端十月 05, 2021 11:54:13 上午 io.netty.handler.logging.LoggingHandler channelRegistered信息: [id: 0x4d75c580] REGISTERED十月 05, 2021 11:54:13 上午 io.netty.handler.logging.LoggingHandler connect信息: [id: 0x4d75c580] CONNECT: /127.0.0.1:9527十月 05, 2021 11:54:13 上午 io.netty.handler.logging.LoggingHandler channelActive信息: [id: 0x4d75c580, L:/127.0.0.1:54030 - R:/127.0.0.1:9527] ACTIVE[INFO] [2021-10-05 11:54:13.403] [Thread-0] [c.g.h.r.c.c.RpcClient.run] - RPC 服务启动客户端完成，监听端口：9527十月 05, 2021 11:54:13 上午 io.netty.handler.logging.LoggingHandler write信息: [id: 0x4d75c580, L:/127.0.0.1:54030 - R:/127.0.0.1:9527] WRITE: 8B         +-------------------------------------------------+         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |+--------+-------------------------------------------------+----------------+|00000000| 00 00 00 01 00 00 00 02                         |........        |+--------+-------------------------------------------------+----------------+十月 05, 2021 11:54:13 上午 io.netty.handler.logging.LoggingHandler flush信息: [id: 0x4d75c580, L:/127.0.0.1:54030 - R:/127.0.0.1:9527] FLUSH[INFO] [2021-10-05 11:54:13.450] [nioEventLoopGroup-2-1] [c.g.h.r.c.c.RpcClient.channelActive] - [Client] request is :CalculateRequest{one=1, two=2}十月 05, 2021 11:54:13 上午 io.netty.handler.logging.LoggingHandler channelRead信息: [id: 0x4d75c580, L:/127.0.0.1:54030 - R:/127.0.0.1:9527] READ: 5B         +-------------------------------------------------+         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |+--------+-------------------------------------------------+----------------+|00000000| 01 00 00 00 03                                  |.....           |+--------+-------------------------------------------------+----------------+十月 05, 2021 11:54:13 上午 io.netty.handler.logging.LoggingHandler channelReadComplete信息: [id: 0x4d75c580, L:/127.0.0.1:54030 - R:/127.0.0.1:9527] READ COMPLETE[INFO] [2021-10-05 11:54:13.508] [nioEventLoopGroup-2-1] [c.g.h.r.c.c.RpcClient.channelRead0] - [Client] response is :CalculateResponse{success=true, sum=3}

可以看到，输出了对应的请求参数和响应结果。

当然，此时服务端也有对应的新增日志：

十月 05, 2021 11:54:13 上午 io.netty.handler.logging.LoggingHandler channelRead信息: [id: 0xd399474f, L:/0:0:0:0:0:0:0:0:9527] READ: [id: 0xbc9f5927, L:/127.0.0.1:9527 - R:/127.0.0.1:54030]十月 05, 2021 11:54:13 上午 io.netty.handler.logging.LoggingHandler channelReadComplete信息: [id: 0xd399474f, L:/0:0:0:0:0:0:0:0:9527] READ COMPLETE[INFO] [2021-10-05 11:54:13.432] [nioEventLoopGroup-2-1] [c.g.h.r.s.h.RpcServerHandler.channelActive] - [Server] channel {} connected 00e04cfffe360988-00001d34-00000001-2a80d950d8166c0c-bc9f5927[INFO] [2021-10-05 11:54:13.495] [nioEventLoopGroup-2-1] [c.g.h.r.s.h.RpcServerHandler.channelRead0] - [Server] receive channel 00e04cfffe360988-00001d34-00000001-2a80d950d8166c0c-bc9f5927 request: CalculateRequest{one=1, two=2} from [INFO] [2021-10-05 11:54:13.505] [nioEventLoopGroup-2-1] [c.g.h.r.s.h.RpcServerHandler.channelRead0] - [Server] channel 00e04cfffe360988-00001d34-00000001-2a80d950d8166c0c-bc9f5927 response CalculateResponse{success=true, sum=3}

小结

为了便于大家学习，以上源码已经开源：

希望本文对你有所帮助，如果喜欢，欢迎点赞收藏转发一波。

我是老马，期待与你的下次相遇。