springboot开发grpc接口

依赖

<!-- grpc相关依赖 -->
<dependency>
    <groupId>com.google.protobuf</groupId>
    <artifactId>protobuf-java</artifactId>
    <version>3.6.1</version>
</dependency>
<dependency>
    <groupId>io.grpc</groupId>
    <artifactId>grpc-protobuf</artifactId>
    <version>1.23.0</version>
</dependency>
<dependency>
    <groupId>io.grpc</groupId>
    <artifactId>grpc-stub</artifactId>
    <version>1.23.0</version>
</dependency>
<dependency>
    <groupId>io.grpc</groupId>
    <artifactId>grpc-netty</artifactId>
    <version>1.23.0</version>
</dependency>
<dependency>
    <groupId>io.grpc</groupId>
    <artifactId>grpc-netty-shaded</artifactId>
    <version>1.23.0</version>
</dependency>
<dependency>
    <groupId>io.grpc</groupId>
    <artifactId>grpc-okhttp</artifactId>
    <version>1.23.0</version>
</dependency>

插件

<build>
    <extensions>
        <extension>
            <groupId>kr.motd.maven</groupId>
            <artifactId>os-maven-plugin</artifactId>
            <version>1.5.0.Final</version>
        </extension>
    </extensions>
    <plugins>
        <plugin>
            <groupId>org.xolstice.maven.plugins</groupId>
            <artifactId>protobuf-maven-plugin</artifactId>
            <version>0.5.1</version>
            <configuration>
                <protocArtifact>com.google.protobuf:protoc:3.5.1-1:exe:${os.detected.classifier}</protocArtifact>
                <pluginId>grpc-java</pluginId>
                <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.14.0:exe:${os.detected.classifier}</pluginArtifact>
            </configuration>
            <executions>
                <execution>
                    <goals>
                        <goal>compile</goal>
                        <goal>compile-custom</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

设计proto

在src/main目录(java同级目录)下新建proto目录.
在proto目录下新建文件hello.proto

syntax = "proto3";

option java_multiple_files = true;
option java_package = "com.example.java.grpc";
option java_outer_classname = "HelloWorldProto";
option objc_class_prefix = "GRPC";

package common;

service HelloService {
    rpc SayHello (Hello) returns (Response) {
    }
}

message Hello {
    string name = 1;
}

message Response {
    string content = 1;
}

生成Java文件

mvn protobuf:compile
mvn protobuf:compile-custom

编写服务端

server:
  grpc:
    port: 9090

@Service
public class GrpcServer {
    // 配置文件中定义端口号
    @Value("${server.grpc.port}")
    Integer port;
    private Server server;

    @PostConstruct
    protected void start() throws IOException {
        server = ServerBuilder.forPort(port)
                .addService(new HelloServiceImpl())
                .build()
                .start();
        log.info("Grpc Server started, listening on " + port);
        Runtime.getRuntime().addShutdownHook(new Thread(() -> {
            System.err.println("shutting down gRPC java server ...");
            GrpcServer.this.stop();
        }));
    }

    private void stop() {
        if (server != null) {
            server.shutdown();
        }
    }

    protected void blockUntilShutdown() throws InterruptedException {
        if (server != null) {
            server.awaitTermination();
        }
    }

    private class HelloServiceImpl extends HelloServiceGrpc.HelloServiceImplBase {

        @Override
        public void sayHello(Hello req, StreamObserver<Response> responseObserver) {
            Response reply = Response.newBuilder().setContent(("Response Message from Java gRPC-Server: Hello " + req.getName())).build();
            responseObserver.onNext(reply);
            responseObserver.onCompleted();
        }
    }

}

编写客户端

@Slf4j
public class GrpcClient {
    private ManagedChannel channel;
    private HelloServiceGrpc.HelloServiceBlockingStub blockingStub;

    public GrpcClient(String host, int port) {
        channel = ManagedChannelBuilder.forAddress(host, port)
                .usePlaintext(true)
                .build();
        blockingStub = HelloServiceGrpc.newBlockingStub(channel);
    }


    public void shutdown() throws InterruptedException {
        channel.shutdown().awaitTermination(5, TimeUnit.SECONDS);
    }

    public String sayHello(String name) {
        Hello request = Hello.newBuilder().setName(name).build();
        Response response;
        try {
            response = blockingStub.sayHello(request);
            return response.getContent();
        } catch (StatusRuntimeException e) {
            log.warn("RPC failed: {}", e.getStatus());
            return "RPC failed";
        }
    }
}