RPC框架——gRPC简单示例

1. 简介

Google gRPC 是一款RPC框架
官方网址: gRPC
主要支持： C/C++, C#, Dart, GO, Java, Objective-C, Python, PHP, Ruby, Node.js
gRPC主要由2部分构成
- 远程过程调用
- 数据序列化/反序列化 (Protocol Buffers)

2. 将*.proto 协议文件转换为语言源文件

安装Maven插件（用于编译*.proto 文件）

<build>
   <extensions>
       <extension>
           <groupId>kr.motd.maven</groupId>
           <artifactId>os-maven-plugin</artifactId>
           <version>1.6.2</version>
       </extension>
   </extensions>
   <plugins>
       <plugin>
           <groupId>org.xolstice.maven.plugins</groupId>
           <artifactId>protobuf-maven-plugin</artifactId>
           <version>0.6.1</version>
           <configuration>
               <protocArtifact>com.google.protobuf:protoc:3.10.0:exe:${os.detected.classifier}</protocArtifact>
               <pluginId>grpc-java</pluginId>
               <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.25.0:exe:${os.detected.classifier}</pluginArtifact>
           </configuration>
           <executions>
               <execution>
                   <goals>
                       <goal>compile</goal>
                       <goal>compile-custom</goal>
                   </goals>
               </execution>
           </executions>
       </plugin>
   </plugins>
</build>

编写 my_protocol.proto文件（官方IDL说明）

syntax = "proto3";

// 包名
package com.skey.grpcdemo.grpc;

option java_package = "com.skey.grpcdemo.grpc";
//option java_outer_classname = "PersonProto";
option java_multiple_files = true;

// 定义一个JavaBean
message Person {
    int32 id = 1;
    string name = 2;
    int32 age = 3;
}

// 定义一个请求
message MyRequest {
    int32 id = 1;
}

// 定义一个响应
message MyResponse {
    int32 statusCode = 1;
    Person person = 2;
}

// 编译一个RPC服务
service PersonService {

    // 定义一个方法getPeronById，传入MyRequest，返回MyResponse
    rpc getPersonById (MyRequest) returns (MyResponse) {
    }

    // 定义一个方法getPersons，传入MyRequest，返回多个MyResponse(同理，你还可以发送多个Request)
    rpc getPersons (MyRequest) returns (stream MyResponse) {
    }

}

编译*.proto文件，转化为语言源文件
- 在main目录下创建proto文件夹，将my_protocol.proto文件放入其中
- 执行命令 mvn compile
- maven会自动寻找main/proto/下的*.proto文件，进行编译转换
- 生成的class文件存放在target/classs/下
- 生成的源文件存放在target/generated-sources/下

3. 使用 gRPC 编写服务端/客户端

引入Maven依赖（当前版本 1.25.0）

<dependency>
   <groupId>io.grpc</groupId>
   <artifactId>grpc-netty-shaded</artifactId>
   <version>1.25.0</version>
</dependency>
<dependency>
   <groupId>io.grpc</groupId>
   <artifactId>grpc-protobuf</artifactId>
   <version>1.25.0</version>
</dependency>
<dependency>
   <groupId>io.grpc</groupId>
   <artifactId>grpc-stub</artifactId>
   <version>1.25.0</version>
</dependency>

服务端示例

PersonServiceImpl.java

package com.skey.grpcdemo;

import com.skey.grpcdemo.grpc.MyRequest;
import com.skey.grpcdemo.grpc.MyResponse;
import com.skey.grpcdemo.grpc.Person;
import com.skey.grpcdemo.grpc.PersonServiceGrpc;
import io.grpc.stub.StreamObserver;

/**
 * Description: 服务实现类
 * <br/>
 * Date: 2019/12/18 22:03
 *
 * @author ALion
 */
public class PersonServiceImpl extends PersonServiceGrpc.PersonServiceImplBase {

    @Override
    public void getPersonById(MyRequest request, StreamObserver<MyResponse> responseObserver) {
        System.out.println("PersonServiceImpl.getPersonById");

        MyResponse.Builder builder = MyResponse.newBuilder();

        int id = request.getId();
        if (id > 105) {
            // 如果id大于，返回失败的状态码0
            builder.setStatusCode(0);
        } else {
            Person person = Person.newBuilder()
                    .setId(id)
                    .setName("laowang")
                    .setAge(28)
                    .build();

            builder.setStatusCode(1).setPerson(person);
        }

        responseObserver.onNext(builder.build());

        // 消息发送完成
        responseObserver.onCompleted();
    }

    @Override
    public void getPersons(MyRequest request, StreamObserver<MyResponse> responseObserver) {
        System.out.println("PersonServiceImpl.getPersons");

        for (int i = 0; i < 5; i++) {
            Person person = Person.newBuilder()
                    .setId(i)
                    .setName("laowang")
                    .setAge(28)
                    .build();
            MyResponse response = MyResponse.newBuilder()
                    .setStatusCode(1)
                    .setPerson(person)
                    .build();

            responseObserver.onNext(response);
        }
        responseObserver.onCompleted();
    }
}

ServerDemo.java

package com.skey.grpcdemo;

import io.grpc.Server;
import io.grpc.ServerBuilder;

/**
 * Description: 服务端示例
 * <br/>
 * Date: 2019/12/18 22:15
 *
 * @author ALion
 */
public class ServerDemo {

    public static void main(String[] args) {
        // 构建Server
        Server server = ServerBuilder.forPort(10086)
                .addService(new PersonServiceImpl())
                .build();
        try {
            // 启动
            server.start();

            // 阻塞Server
            server.awaitTermination();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

客户端示例

ClientDemo.java

package com.skey.grpcdemo;

import com.skey.grpcdemo.grpc.MyRequest;
import com.skey.grpcdemo.grpc.MyResponse;
import com.skey.grpcdemo.grpc.PersonServiceGrpc;
import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;

import java.util.Iterator;

/**
 * Description: 客户端示例
 * <br/>
 * Date: 2019/12/18 22:15
 *
 * @author ALion
 */
public class ClientDemo {

    public static void main(String[] args) {
        // 构建客户端
        ManagedChannel managedChannel = ManagedChannelBuilder
                .forAddress("localhost",10086)
                .usePlaintext()
                .build();
        PersonServiceGrpc.PersonServiceBlockingStub blockingStub = PersonServiceGrpc.newBlockingStub(managedChannel);

        for (int i = 100; i < 107; i++) {
            // 构建Request
            MyRequest request = MyRequest.newBuilder()
                    .setId(i)
                    .build();
            // 发送Request，获得Response
            MyResponse response = blockingStub.getPersonById(request);

            // 解析状态码
            if (response.getStatusCode() == 1) {
                System.out.println(response.getPerson());
            } else {
                System.out.println("No such person that id = " + i);
            }

            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

        System.out.println("------------------------------------------");

        // 返回多个 MyResponse
        MyRequest request = MyRequest.newBuilder()
                .setId(1)
                .build();
        Iterator<MyResponse> responseIter = blockingStub.getPersons(request);
        responseIter.forEachRemaining(System.out::println);

    }

}

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RPC框架——gRPC简单示例

文章目录

RPC框架——gRPC简单示例

1. 简介

2. 将*.proto 协议文件转换为语言源文件

3. 使用 gRPC 编写服务端/客户端

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