gRPC--JAVA(单项RPC)

服务端

@Component
public class Greeter extends GreeterGrpc.GreeterImplBase implements InitializingBean {

 //streamObserver 一个应答的观察者
    @Override
    public void sayHello(Helloworld.HelloRequest request,
                         io.grpc.stub.StreamObserver<Helloworld.HelloReply> responseObserver) {
        Helloworld.HelloReply helloReply = Helloworld.HelloReply.newBuilder().setMessage("hello world").build();
        //添加返回值，完成调用
        responseObserver.onNext(helloReply);//添加返回值
        responseObserver.onCompleted();//完成调用
    }
 @Override
    public void afterPropertiesSet() throws Exception {

        int port = 9098;
        ServerBuilder.forPort(port)
                .addService(new Greeter())
                .build()
                .start();
        System.out.println("server port:"+port);

    }
}

* 继承GreeterGrpc.GreeterImplBase重写里面的sayHello方法；GreeterGrpc.GreeterImplBase就是我们在proto文件中定义的服务
* ServerBuilder的forPort方法用来指定一个端口，用addService来添加一个服务类，也就是当前类

* grpc生成的消息类有点独特，他们没有set方法，只有get方法，想要賦值，要用他们的一个内部类Builder来间接賦值
* Helloworld.HelloReply helloReply = Helloworld.HelloReply.newBuilder().setMessage("liuwenhui").build();

客户端

@RunWith(SpringRunner.class)
@SpringBootTest
public class GrpcApplicationTests {

    @Autowired
    private JavaGrpcClient javaGrpcClient;

    @Test
    public void contextLoads() {

        /*Helloworld.HelloRequest request = Helloworld.HelloRequest.newBuilder().setName("lwh").build();
        Helloworld.HelloReply helloReply = javaGrpcClient.run(o->o.sayHello(request));
        System.out.println(helloReply.getMessage());*/
        Channel channel = ManagedChannelBuilder
                .forAddress("127.0.0.1", 9098)//服务端
                .usePlaintext(true)//usePlaintext的意思是使用明文不加密(应该可以加密)
                .build();
        //创建阻塞的/同步存根 blockingStub
        GreeterGrpc.GreeterBlockingStub blockingStub = GreeterGrpc.newBlockingStub(channel);
        Helloworld.HelloRequest request = Helloworld.HelloRequest.newBuilder().setName("lwh").build();
        //调用服务器方法
        Helloworld.HelloReply helloReply = blockingStub.sayHello(request);
        System.out.println(helloReply.getMessage());

    }
}