说明
java 从零开始手写 RPC (01) 基于 socket 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。
