手写RPC框架系列(十) - 客户端与服务端示例及调用流程

RPC 手写系列

手写RPC框架系列(十) - 客户端与服务端示例及调用流程

在前面的章节中，我们详细探讨了RPC框架的各个组成部分，包括网络通信、编解码、请求处理和应答等。本章将通过创建客户端和服务端的示例模块，来演示如何使用我们自己实现的 RPC 框架进行远程方法调用。

本章的大致内容如下：

创建公共 API 模块。
创建客户端示例。
创建服务端示例。
发起 RPC 调用以及观察调用结果。

1. 创建 rpc-example-api 模块

首先，我们创建一个名为 rpc-example-api 的Maven模块，用于存放服务接口和实体类。

rpc-example-api模块结构

在pom.xml中添加必要的依赖和配置。

   <?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">
       <parent>
           <artifactId>rpc-example</artifactId>
           <groupId>com.suny.rpc</groupId>
           <version>1.0.0-SNAPSHOT</version>
       </parent>
       <modelVersion>4.0.0</modelVersion>
       <artifactId>rpc-example-api</artifactId>
       <packaging>jar</packaging>
   
       <properties>
           <maven.compiler.source>8</maven.compiler.source>
           <maven.compiler.target>8</maven.compiler.target>
       </properties>
   
   </project>

创建一个接口 UserService，定义要调用的远程方法 selectById。

   package com.suny.rpc.nettyrpc.api;
   
   public interface UserService {
   
       User selectById(String id);
   
   }

创建实体类，用于方法返回值。

   package com.suny.rpc.nettyrpc.api;
   
   import lombok.Data;
   
   import java.io.Serializable;
   
   @Data
   public class User implements Serializable {
   
       private String id;
   
       private String username;
   }

2. 客户端示例

首先，我们创建一个Maven模块，命名为rpc-example-client，用于演示如何使用RPC框架的客户端。

rpc-example-client模块

在 pom.xml 中添加对 rpc-core 模块的依赖。

   <?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">
       <parent>
           <artifactId>rpc-example</artifactId>
           <groupId>com.suny.rpc</groupId>
           <version>1.0.0-SNAPSHOT</version>
       </parent>
       <modelVersion>4.0.0</modelVersion>
       <artifactId>rpc-example-client</artifactId>
   
       <properties>
           <maven.compiler.source>8</maven.compiler.source>
           <maven.compiler.target>8</maven.compiler.target>
       </properties>
   
       <dependencies>
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter-web</artifactId>
           </dependency>
           <dependency>
               <groupId>com.suny.rpc</groupId>
               <artifactId>rpc-core</artifactId>
               <version>1.0.0-SNAPSHOT</version>
           </dependency>
   
           <dependency>
               <groupId>com.suny.rpc</groupId>
               <artifactId>rpc-example-api</artifactId>
               <version>1.0.0-SNAPSHOT</version>
           </dependency>
   
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter</artifactId>
           </dependency>
       </dependencies>
   
       <build>
           <plugins>
               <plugin>
                   <groupId>org.apache.maven.plugins</groupId>
                   <artifactId>maven-compiler-plugin</artifactId>
                   <version>3.8.1</version>
                   <configuration>
                       <source>1.8</source>
                       <target>1.8</target>
                       <encoding>UTF-8</encoding>
                   </configuration>
               </plugin>
               <plugin>
                   <groupId>org.springframework.boot</groupId>
                   <artifactId>spring-boot-maven-plugin</artifactId>
                   <version>2.3.7.RELEASE</version>
                   <configuration>
                       <mainClass>com.suny.rpc.nettyrpc.client.NettyRpcApplication</mainClass>
                   </configuration>
                   <executions>
                       <execution>
                           <id>repackage</id>
                           <goals>
                               <goal>repackage</goal>
                           </goals>
                       </execution>
                   </executions>
               </plugin>
           </plugins>
       </build>
   
   </project>

定义 Spring Boot 启动类 RpcClientApplication

   package com.suny.rpc.nettyrpc.client;
   
   import com.suny.rpc.nettyrpc.core.annotations.RpcServiceScan;
   import com.suny.rpc.nettyrpc.core.client.NettyClient;
   import com.suny.rpc.nettyrpc.core.serialize.SerializerFactory;
   import org.springframework.beans.factory.annotation.Autowired;
   import org.springframework.boot.CommandLineRunner;
   import org.springframework.boot.SpringApplication;
   import org.springframework.boot.autoconfigure.SpringBootApplication;
   
   import java.util.concurrent.CountDownLatch;
   
   @RpcServiceScan
   @SpringBootApplication(scanBasePackages = {"com.suny.rpc.nettyrpc.**"})
   public class RpcClientApplication implements CommandLineRunner {
   
       @Autowired
       private SerializerFactory serializerFactory;
   
       public static void main(String[] args) {
           SpringApplication.run(RpcClientApplication.class, args);
       }
   
       @Override
       public void run(String... args) throws Exception {
           NettyClient nettyClient = new NettyClient(serializerFactory);
   
           new CountDownLatch(1).await();
       }
   }

创建一个BffService 用于调用远程的 UserService.selectById() 函数。

   package com.suny.rpc.nettyrpc.client;
   
   import com.suny.rpc.nettyrpc.api.User;
   import com.suny.rpc.nettyrpc.api.UserService;
   import com.suny.rpc.nettyrpc.core.annotations.Reference;
   import lombok.extern.slf4j.Slf4j;
   import org.springframework.stereotype.Service;
   
   @Service
   @Slf4j
   public class BffService {
   
       @Reference
       private UserService userService;
   
   
       public User getUserInfo() {
           String userId = "1";
           User user = userService.selectById(userId);
           log.debug("getUserInfo rpc调用结果: {}", user.toString());
           return user;
       }
   
   
   }

创建 BffController 用于暴露 Http 方法供我们测试

   package com.suny.rpc.nettyrpc.client;
   
   import com.suny.rpc.nettyrpc.api.User;
   import org.springframework.beans.factory.annotation.Autowired;
   import org.springframework.web.bind.annotation.GetMapping;
   import org.springframework.web.bind.annotation.RequestMapping;
   import org.springframework.web.bind.annotation.RestController;
   
   @RequestMapping("/test")
   @RestController
   public class BffController {
   
       @Autowired
       private BffService bffService;
   
       @GetMapping
       public User testUser() {
           return bffService.getUserInfo();
       }
   }

3. 服务端示例

接下来，我们创建一个Maven模块，命名为rpc-example-server，用于演示 RPC 框架的服务端例子。

rpc-example-server模块

在 pom.xml 中添加对 rpc-core 模块的依赖。

   <?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">
       <parent>
           <artifactId>rpc-example</artifactId>
           <groupId>com.suny.rpc</groupId>
           <version>1.0.0-SNAPSHOT</version>
       </parent>
       <modelVersion>4.0.0</modelVersion>
       <artifactId>rpc-example-server</artifactId>
       <packaging>jar</packaging>
   
       <properties>
           <maven.compiler.source>8</maven.compiler.source>
           <maven.compiler.target>8</maven.compiler.target>
       </properties>
   
       <dependencies>
           <dependency>
               <groupId>com.suny.rpc</groupId>
               <artifactId>rpc-core</artifactId>
               <version>1.0.0-SNAPSHOT</version>
           </dependency>
           <dependency>
               <groupId>com.suny.rpc</groupId>
               <artifactId>rpc-example-api</artifactId>
               <version>1.0.0-SNAPSHOT</version>
           </dependency>
           <dependency>
               <groupId>org.springframework.boot</groupId>
               <artifactId>spring-boot-starter</artifactId>
           </dependency>
       </dependencies>
   
       <build>
           <plugins>
               <plugin>
                   <groupId>org.apache.maven.plugins</groupId>
                   <artifactId>maven-compiler-plugin</artifactId>
                   <version>3.8.1</version>
                   <configuration>
                       <source>1.8</source>
                       <target>1.8</target>
                       <encoding>UTF-8</encoding>
                   </configuration>
               </plugin>
               <plugin>
                   <groupId>org.springframework.boot</groupId>
                   <artifactId>spring-boot-maven-plugin</artifactId>
                   <version>2.3.7.RELEASE</version>
                   <configuration>
                       <mainClass>com.suny.rpc.nettyrpc.server.RpcServerApplication</mainClass>
                   </configuration>
                   <executions>
                       <execution>
                           <id>repackage</id>
                           <goals>
                               <goal>repackage</goal>
                           </goals>
                       </execution>
                   </executions>
               </plugin>
           </plugins>
       </build>
   
   </project>

创建 Spring Boot 启动类 RpcServerApplication

   package com.suny.rpc.nettyrpc.server;
   
   import com.suny.rpc.nettyrpc.core.annotations.RpcServiceScan;
   import com.suny.rpc.nettyrpc.core.serialize.SerializerFactory;
   import com.suny.rpc.nettyrpc.core.server.NettyServer;
   import com.suny.rpc.nettyrpc.core.server.NettyServerProperties;
   import org.springframework.beans.factory.annotation.Autowired;
   import org.springframework.boot.CommandLineRunner;
   import org.springframework.boot.SpringApplication;
   import org.springframework.boot.autoconfigure.SpringBootApplication;
   
   import java.util.concurrent.CountDownLatch;
   
   @RpcServiceScan(basePackages = "com.suny.rpc.nettyrpc.**")
   @SpringBootApplication
   public class RpcServerApplication implements CommandLineRunner {
   
       @Autowired
       private SerializerFactory serializerFactory;
   
       @Autowired
       private NettyServerProperties nettyServerProperties;
   
       public static void main(String[] args) {
           SpringApplication.run(RpcServerApplication.class, args);
       }
   
       @Override
       public void run(String... args) throws Exception {
           new NettyServer(nettyServerProperties.getServerPort(), serializerFactory);
           new CountDownLatch(1).await();
       }
   }

实现接口 UserService 并注册到 RPC 工厂中

   package com.suny.rpc.nettyrpc.server.biz;
   
   import com.suny.rpc.nettyrpc.api.User;
   import com.suny.rpc.nettyrpc.api.UserService;
   import com.suny.rpc.nettyrpc.core.annotations.RpcService;
   import org.apache.commons.lang3.RandomStringUtils;
   
   
   @RpcService
   public class UserServiceImpl implements UserService {
   
       @Override
       public User selectById(String id) {
           User user = new User();
           user.setId(id);
           user.setUsername(RandomStringUtils.randomAlphabetic(5));
           return user;
       }
   }

4. 发起调用与结果

启动本地的 Zookeeper ，端口号为 2181。
启动 RpcServerApplication 。
启动 RpcServerApplication。
调用客户端测试 Http 接口 :

   curl http://localhost:8080/test/

可以看到控制台输出了远程方法调用的结果：

   getUserInfo rpc调用结果: User(id=1001, username=用户名)

5. 总结

本章我们通过创建客户端和服务端的示例模块，演示了如何使用自己实现的RPC框架进行远程方法调用。了解了客户端如何通过代理对象发起调用，服务端如何注册和处理请求，以及调用结果的返回过程。

同时通过展示了我们的 RPC 框架的基本使用方法，起到一个边学边实践的效果。