开发第一个gPRC的开发

protoc --java_out=/xxx/xxx  /xxx/xxx/xx.proto

pom.xml
 <dependencies>
        <dependency>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-netty-shaded</artifactId>
            <version>1.52.1</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-protobuf</artifactId>
            <version>1.52.1</version>
        </dependency>
        <dependency>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-stub</artifactId>
            <version>1.52.1</version>
        </dependency>
        <dependency> <!-- necessary for Java 9+ -->
            <groupId>org.apache.tomcat</groupId>
            <artifactId>annotations-api</artifactId>
            <version>6.0.53</version>
            <scope>provided</scope>
        </dependency>
 </dependencies>
<build>
        <extensions>
            <extension>
                <groupId>kr.motd.maven</groupId>
                <artifactId>os-maven-plugin</artifactId>
                <version>1.7.1</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:3.21.7:exe:${os.detected.classifier}</protocArtifact>
                    <pluginId>grpc-java</pluginId>
                    <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.52.1:exe:${os.detected.classifier}</pluginArtifact>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>compile</goal>
                            <goal>compile-custom</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

1. 实现业务接口 添加具体的功能 （MyBatis+MySQL)
   public class HelloServiceImpl extends HelloServiceGrpc.HelloServiceImplBase {
    /*
      1. 接受client提交的参数  request.getParameter()
      2. 业务处理 service+dao 调用对应的业务功能。
      3. 提供返回值
     */
    @Override
    public void hello(HelloProto.HelloRequest request, StreamObserver<HelloProto.HelloResponse> responseObserver) {
        //1.接受client的请求参数
        String name = request.getName();
        //2.业务处理
        System.out.println("name parameter "+name);
        //3.封装响应
        //3.1 创建相应对象的构造者
        HelloProto.HelloResponse.Builder builder = HelloProto.HelloResponse.newBuilder();
        //3.2 填充数据
        builder.setResult("hello method invoke ok");
        //3.3 封装响应
        HelloProto.HelloResponse helloResponse = builder.build();
        responseObserver.onNext(helloResponse);
        responseObserver.onCompleted();;
    }
}
2. 创建服务端 （Netty)
public class GprcServer1 {
    public static void main(String[] args) throws IOException, InterruptedException {
        //1. 绑定端口 
        ServerBuilder serverBuilder = ServerBuilder.forPort(9000);
        //2. 发布服务
        serverBuilder.addService(new HelloServiceImpl());
        //serverBuilder.addService(new UserServiceImpl());
        //3. 创建服务对象
        Server server = serverBuilder.build();
        server.start();
        server.awaitTermination();;
    }
}

1. client通过代理对象完成远端对象的调用
public class GprcClient1 {
    public static void main(String[] args) {
        //1 创建通信的管道
        ManagedChannel managedChannel = ManagedChannelBuilder.forAddress("localhost", 9000).usePlaintext().build();
        //2 获得代理对象 stub
        try {
            HelloServiceGrpc.HelloServiceBlockingStub helloService = HelloServiceGrpc.newBlockingStub(managedChannel);
            //3. 完成RPC调用
            //3.1 准备参数
            HelloProto.HelloRequest.Builder builder = HelloProto.HelloRequest.newBuilder();
            builder.setName("sunshuai");
            HelloProto.HelloRequest helloRequest = builder.build();
            //3.1 进行功能rpc调用，获取相应的内容
            HelloProto.HelloResponse helloResponse = helloService.hello(helloRequest);
            String result = helloResponse.getResult();
            System.out.println("result = " + result);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }finally {
            managedChannel.shutdown();
        }
    }
}

服务端 处理返回值时
responseObserver.onNext(helloResponse1);  //通过这个方法 把响应的消息 回传client
responseObserver.onCompleted();           //通知client 整个服务结束。底层返回标记 
                                          // client就会监听标记 【grpc做的】
requestObserver.onNext(helloRequest1);
requestObserver.onCompleted();