直接使用

maven依赖

<!--jar包依赖-->
<dependencies>
  <dependency>
    <groupId>io.grpc</groupId>
    <artifactId>grpc-all</artifactId>
  </dependency>
</dependencies>
<!--protobuf-maven-plugin插件-->
<plugin>
  <groupId>org.xolstice.maven.plugins</groupId>
  <artifactId>protobuf-maven-plugin</artifactId>
  <version>0.6.1</version>
  <configuration>
    <!--suppress UnresolvedMavenProperty -->
    <protocArtifact>com.google.protobuf:protoc:${protoc.version}:exe:${os.detected.classifier}
    </protocArtifact>
    <pluginId>grpc-java</pluginId>
    <!--suppress UnresolvedMavenProperty -->
    <pluginArtifact>io.grpc:protoc-gen-grpc-java:${grpc.version}:exe:${os.detected.classifier}
    </pluginArtifact>
  </configuration>
  <executions>
    <execution>
      <goals>
        <goal>compile</goal>
        <goal>compile-custom</goal>
      </goals>
    </execution>
  </executions>
</plugin>

proto文件定义

syntax = "proto3"; // 协议版本
// 选项配置
option java_package = "com.example";
option java_outer_classname = "RPCDateServiceApi";
option java_multiple_files = true;
// 定义包名
package com.example;
// 服务接口.定义请求参数和相应结果  会生成RPCDateServiceGrpc接口
service RPCDateService {
  rpc getDate (RPCDateRequest) returns (RPCDateResponse) {
  }
}
// 定义请求体
message RPCDateRequest {
string userName = 1;
}
// 定义相应内容
message RPCDateResponse {
string serverDate = 1;
}

生成Bean和接口

定义接口实现类 （RPCDateServiceGrpc的实现类）

public class RPCDateServiceImpl extends RPCDateServiceGrpc.RPCDateServiceImplBase {
    @Override
    public void getDate(RPCDateRequest request, StreamObserver<RPCDateResponse> responseObserver) {
        // 请求结果,我们定义的
        RPCDateResponse rpcDateResponse = null;
        String userName = request.getUserName();
        String response = String.format("你好: %s, 今天是%s.", userName,
                                        new SimpleDateFormat("yyyy-MM-dd HH:mm:ss: a").format(new Date()));
        try {
            // 定义响应,是一个builder构造器.
            rpcDateResponse = RPCDateResponse
                .newBuilder()
                .setServerDate(response)
                .build();
        } catch (Exception e) {
            responseObserver.onError(e);
        } finally {
            // 这种写法是observer,异步写法,老外喜欢用这个框架.
            responseObserver.onNext(rpcDateResponse);
        }
        responseObserver.onCompleted();
    }
}

服务端

public class GRPCServer {
    private static final int port = 9999;
    public static void main(String[] args) throws Exception {
        // 设置service接口.
        Server server = ServerBuilder.
                forPort(port)
                .addService(new RPCDateServiceImpl())
                .build().start();
        System.out.println(String.format("GRpc服务端启动成功, 端口号: %d.", port));
        server.awaitTermination();
    }
}

客户端

public class GRPCClient {
    private static final String host = "127.0.0.1";
    private static final int serverPort = 9999;
    public static void main(String[] args) throws Exception {
        // 1. 拿到一个通信的channel
        ManagedChannel managedChannel = ManagedChannelBuilder.forAddress(host, serverPort).usePlaintext().build();
        try {
            // 2.拿到道理对象
            RPCDateServiceGrpc.RPCDateServiceBlockingStub rpcDateService = RPCDateServiceGrpc.newBlockingStub(managedChannel);
            for (int i = 0; i < 5; i++) {
                RPCDateRequest rpcDateRequest = RPCDateRequest
                        .newBuilder()
                        .setUserName("anthony"+i)
                        .build();
                // 3. 请求
                RPCDateResponse rpcDateResponse = rpcDateService.getDate(rpcDateRequest);
                // 4. 输出结果
                System.out.println(rpcDateResponse.getServerDate());
                Thread.sleep(2000);
            }
        } finally {
            // 5.关闭channel, 释放资源.
            managedChannel.shutdown();
        }
    }
}

结果