使用 @GrpcClient 实现客户端

@GrpcClient("greeter")
private GreeterGrpc.GreeterBlockingStub greeterStub;
@GrpcClient("calculator")
private CalculatorGrpc.CalculatorBlockingStub calculatorStub;

<dependency>
    <groupId>net.devh</groupId>
    <artifactId>grpc-client-spring-boot-starter</artifactId>
    <version>2.12.0.RELEASE</version>
</dependency>
<dependency>
　　<groupId>io.grpc</groupId>
　　<artifactId>grpc-netty-shaded</artifactId>
　　<version>1.37.0</version>
</dependency>
<dependency>
　　<groupId>io.grpc</groupId>
　　<artifactId>grpc-protobuf</artifactId>
　　<version>1.37.0</version>
</dependency>
<dependency>
　　<groupId>io.grpc</groupId>
　　<artifactId>grpc-stub</artifactId>
　　<version>1.37.0</version>
</dependency>

<build>
    <plugins>
        <plugin>
            <groupId>org.xolstice.maven.plugins</groupId>
            <artifactId>protobuf-maven-plugin</artifactId>
            <version>0.6.1</version>
            <executions>
                <execution>
                    <goals>
                        <goal>compile</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <protocArtifact>com.google.protobuf:protoc:3.12.0:exe:${os.detected.classifier}</protocArtifact>
                <pluginId>grpc-java</pluginId>
                <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.30.2:exe:${os.detected.classifier}</pluginArtifact>
                <outputDirectory>${project.build.directory}/generated-sources/protobuf/java</outputDirectory>
                <clearOutputDirectory>false</clearOutputDirectory>
                <includeCompileClasspath>true</includeCompileClasspath>
            </configuration>
        </plugin>
    </plugins>
</build>

syntax = "proto3";
package com.example.grpcdemo.service;
option java_multiple_files = true;
option java_package = "com.example.grpcdemo.service";
option java_outer_classname = "UserServiceProto";
message UserRequest {
    string name = 1;
    int32 age = 2;
}
message UserResponse {
    string message = 1;
}
service UserService {
    rpc addUser (UserRequest) returns (UserResponse);
    rpc deleteUser (UserRequest) returns (UserResponse);
    rpc updateUser (UserRequest) returns (UserResponse);
    rpc getUser (UserRequest) returns (UserResponse);
}

@Component
public class UserGrpcClient {
    @GrpcClient("user-service-provider") // 指定gRPC服务在配置中的服务名
    private UserServiceGrpc.UserServiceBlockingStub userService;
    public void addUser(UserRequest request) {
        UserResponse response = userService.addUser(request);
        // 处理响应结果
    }
}

grpc:
  client:
    user-service-provider:
      address: localhost            # gRPC服务地址
      port: 6565
      plaintext: true                # 指定是否使用明文连接；
      enableKeepAlive: true            # 是否启用KeepAlive机制
      keepAliveTime: 30s            # KeepAlive时间
      keepAliveTimeout: 5s              # 是否在没有gRPC调用时保持KeepAlive的连接

import com.example.grpcdemo.service.UserRequest;
import com.example.grpcdemo.service.UserResponse;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class UserController {
    @Autowired
    private UserGrpcClient userGrpcClient;
    
    @RequestMapping("/addUser")
    public String addUser(UserRequest request) {
        UserResponse response = userGrpcClient.addUser(request);
        return response.getMessage();
    }
}