gRPC实战（一、快速开始）

1、定义一个服务-useinfoservice.proto

syntax = "proto3";//标识 proto版本 建议使用proto3
package userinfoservice;//proto包名 避免命名冲突，也可以作为引入其他proto文件时使用
option java_package = "com.example.userinfoservice" ;//生成的类将带有此包名，不指定则使用package
option cc_generic_services = true;
option go_package = "./pb";
option java_outer_classname = "UserInfoEntity";//指定生成后的类名，里面会包含req/res,不指定则使用文件名

message GetUserInfoReq{
  string id = 1;
}
message GetUserInfoRes{
  string id = 1;
  string name = 2;
  int32 age = 3;
}

service UserInfoService {
  rpc getUserInfo(GetUserInfoReq) returns (GetUserInfoRes);
}

2、通过proto文件生成代码

1) Go

安装protoc命令

$ go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.28
$ go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.2
$ export PATH="$PATH:$(go env GOPATH)/bin"

生成userinfo.pb.go文件和userinfo_grpc.pb.go

protoc --go_out=. --go_opt=paths=source_relative \
    --go-grpc_out=. --go-grpc_opt=paths=source_relative \
    proto/userinfo.proto

2) Java

将你的proto文件放到src/main/proto和src/test/proto目录，并配置生成代码的插件

Gradle生成代码插件：

/*
 * This file was generated by the Gradle 'init' task.
 *
 * This generated file contains a sample Java application project to get you started.
 * For more details take a look at the 'Building Java & JVM projects' chapter in the Gradle
 * User Manual available at https://docs.gradle.org/7.2/userguide/building_java_projects.html
 */
plugins {
    // Apply the application plugin to add support for building a CLI application in Java.
    id 'application'
    // ASSUMES GRADLE 5.6 OR HIGHER. Use plugin version 0.8.10 with earlier gradle versions
    id 'com.google.protobuf' version '0.8.17'
    // Generate IntelliJ IDEA's .idea & .iml project files
    id 'idea'
    id 'java'
}

sourceCompatibility = 1.8
targetCompatibility = 1.8

repositories {
    // Use Maven Central for resolving dependencies.
    mavenCentral()
    repositories {
        maven { url 'https://maven.aliyun.com/repository/google/' }
        maven { url 'https://maven.aliyun.com/repository/jcenter/'}
    }
}
def grpcVersion = '1.48.0' // CURRENT_GRPC_VERSION
dependencies {
    // Use JUnit test framework.
    testImplementation 'junit:junit:4.13.2'

    // This dependency is used by the application.
    implementation 'com.google.guava:guava:30.1.1-jre'
    implementation "io.grpc:grpc-netty:${grpcVersion}"
    implementation "io.grpc:grpc-protobuf:${grpcVersion}"
    implementation "io.grpc:grpc-services:${grpcVersion}"
    implementation "io.grpc:grpc-stub:${grpcVersion}"
}

application {
    // Define the main class for the application.
    mainClass = 'client.MainApplication'
}
protobuf {
    protoc {
        artifact = "com.google.protobuf:protoc:3.2.0"
    }
    plugins {
        grpc {
            artifact = 'io.grpc:protoc-gen-grpc-java:1.4.0'
        }
    }
    generateProtoTasks {
        all()*.plugins {
            grpc {}
        }
    }
}

Maven生成代码插件：

<build>
  <extensions>
    <extension>
      <groupId>kr.motd.maven</groupId>
      <artifactId>os-maven-plugin</artifactId>
      <version>1.4.1.Final</version>
    </extension>
  </extensions>
  <plugins>
    <plugin>
      <groupId>org.xolstice.maven.plugins</groupId>
      <artifactId>protobuf-maven-plugin</artifactId>
      <version>0.5.0</version>
      <configuration>
        <protocArtifact>com.google.protobuf:protoc:3.3.0:exe:${os.detected.classifier}</protocArtifact>
        <pluginId>grpc-java</pluginId>
        <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.4.0:exe:${os.detected.classifier}</pluginArtifact>
      </configuration>
      <executions>
        <execution>
          <goals>
            <goal>compile</goal>
            <goal>compile-custom</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>

3、对应生成服务端和客户端

（1 ）Java 服务端

package com.example.userinfoservice.impl;

import com.example.userinfoservice.UserInfoEntity;
import com.example.userinfoservice.UserInfoServiceGrpc;
import com.example.userinfoservice.entity.UserInfoData;
import com.google.common.collect.Maps;
import io.grpc.stub.StreamObserver;
import org.apache.commons.lang3.StringUtils;

import java.util.HashMap;

public class UserInfoServiceImpl extends UserInfoServiceGrpc.UserInfoServiceImplBase {

    private HashMap<String, UserInfoData> userinfoHashMap = Maps.newHashMap();

    @Override
    public void getUserInfo(UserInfoEntity.GetUserInfoReq request, StreamObserver<UserInfoEntity.GetUserInfoRes> responseObserver) {

        System.out.println("java服务收到请求");
        if (StringUtils.isEmpty(request.getId())){
            responseObserver.onError(new Exception("id不能为空"));
            responseObserver.onCompleted();
            return;
        }

        if (userinfoHashMap.isEmpty()){
            initUserInfoHashMap();
        }

        UserInfoData userInfoData = userinfoHashMap.get(request.getId());
        if (userInfoData == null){
            responseObserver.onError(new Exception("id不能为空"));
            responseObserver.onCompleted();
            return;
        }
        responseObserver.onNext(UserInfoEntity.GetUserInfoRes.newBuilder()
                .setId(userInfoData.getId())
                .setName(userInfoData.getName())
                .setAge(userInfoData.getAge())
                .build());
        responseObserver.onCompleted();
    }

    private void initUserInfoHashMap() {
        userinfoHashMap.put("1",new UserInfoData("1","小美",24));
        userinfoHashMap.put("2",new UserInfoData("2","小强",28));
        userinfoHashMap.put("3",new UserInfoData("3","小刚",30));
    }
}

实体 UserInfoData

package com.example.userinfoservice.entity;

public class UserInfoData{
    private String id;
    private String name;
    private int age;

    public UserInfoData() {
    }

    public UserInfoData(String id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

服务主类 App

/*
 * This Java source file was generated by the Gradle 'init' task.
 */
package com.example.userinfoservice;

import com.example.userinfoservice.impl.UserInfoServiceImpl;
import io.grpc.Server;
import io.grpc.ServerBuilder;

import java.io.IOException;
import java.util.logging.Logger;

public class App {
    public String getGreeting() {
        return "Hello World!";
    }

    private static final Logger logger = Logger.getLogger(App.class.getName());

    private Server server;

    private void start() throws IOException {
        int port = 10080;
        server = ServerBuilder.forPort(port)
                .addService(new UserInfoServiceImpl())
                .build()
                .start();
        logger.info("Server started, listening on " + port);
        Runtime.getRuntime().addShutdownHook(new Thread(() -> {
            // Use stderr here since the logger may have been reset by its JVM shutdown hook.
            logger.info("*** shutting down gRPC server since JVM is shutting down");
            App.this.stop();
            logger.info("*** server shut down");
        }));
    }

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

    /**
     * Await termination on the main thread since the grpc library uses daemon threads.
     */
    private void blockUntilShutdown() throws InterruptedException {
        if (server != null) {
            server.awaitTermination();
        }
    }

    /**
     * Main launches the server from the command line.
     */
    public static void main(String[] args) throws IOException, InterruptedException {
        final App server = new App();
        server.start();
        server.blockUntilShutdown();
    }
}

（2）Java 客户端

package com.example.userinfoservice;

import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;

import java.util.logging.Logger;

public class MainApplication {

    private static final Logger logger = Logger.getLogger(MainApplication.class.getName());

    public static void main(String[] args) throws InterruptedException {
        ManagedChannel channel = ManagedChannelBuilder.forAddress("localhost", 10080)
                .usePlaintext()
                .build();

        UserInfoServiceGrpc.UserInfoServiceBlockingStub stub =
                UserInfoServiceGrpc.newBlockingStub(channel);

        Userinfo.GetUserInfoRes res = stub.getUserInfo(
                Userinfo.GetUserInfoReq.newBuilder()
                        .setId("1")
                        .build());
        logger.info("用户id: " + res.getId() + "\t用户姓名:"+ res.getName()
        +"\t用户年龄:"+ res.getAge());
        channel.shutdown();
    }
}

（3）go 服务端

实现用户服务

package serviceimpl

import (
	"context"
	"errors"
	"grpc-in-action/part1/go/server/pb"
	"log"
)

type UserInfo struct {
	Id string
	Name string
	Age int32
}
type UserInfoServiceImpl struct {
	UserInfoData map[string]*UserInfo
	pb.UnimplementedUserInfoServiceServer
}

func (server *UserInfoServiceImpl) GetUserInfo(ctx context.Context, in *pb.GetUserInfoReq) (*pb.GetUserInfoRes, error)  {

	log.Printf("go server收到请求")
	//初始化一个map
	if server.UserInfoData == nil{
		server.initUserInfoData()
	}
	data:= server.UserInfoData[in.Id]
	if data == nil{
		return nil,errors.New("该id不存在")
	}
	res := &pb.GetUserInfoRes{
		Id:   data.Id,
		Name: data.Name,
		Age:  data.Age,
	}

	return res,nil
}

func (server *UserInfoServiceImpl) initUserInfoData (){
	server.UserInfoData = make(map[string]*UserInfo)

	server.UserInfoData["1"] = &UserInfo{
		Id:   "1",
		Name: "小美",
		Age:  18,
	}
	server.UserInfoData["2"] = &UserInfo{
		Id:   "2",
		Name: "小刚",
		Age:  28,
	}
	server.UserInfoData["3"] = &UserInfo{
		Id:   "3",
		Name: "小王",
		Age:  20,
	}
}

服务主类

package main

import (
	"google.golang.org/grpc"
	"google.golang.org/grpc/reflection"
	"grpc-in-action/part1/go/server/pb"
	"grpc-in-action/part1/go/server/serviceimpl"
	"log"
	"net"
)

func main() {
	lis, err := net.Listen("tcp", "localhost:10080")
	if err != nil {
		log.Fatalf("failed to listen: %v", err)
	}
	s := grpc.NewServer()
	ser := &serviceimpl.UserInfoServiceImpl{}
	pb.RegisterUserInfoServiceServer(s,ser)
	log.Printf("start")
	reflection.Register(s)
	if err := s.Serve(lis); err != nil {
		log.Fatalf("failed to serve: %v", err)
	}
}

（4）go 客户端

package main

import (
	"context"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials/insecure"
	"grpc-in-action/part1/go/client/pb"
	"log"
)

func main() {

	// Set up a connection to the server.
	conn, err := grpc.Dial("localhost:10080",grpc.WithTransportCredentials(insecure.NewCredentials()))
	if err != nil {
		log.Fatalf("did not connect: %v", err)
	}
	defer conn.Close()
	c := pb.NewUserInfoServiceClient(conn)
	req:= &pb.GetUserInfoReq{Id: "1"}
	res,err :=c.GetUserInfo(context.Background(),req)
	if err != nil {
		log.Fatalf("err:%+v",err)
	}else {
		log.Printf("res:%+v",res)
	}

}

gRPC实战（ 一、快速开始 ）

1、定义一个服务-useinfoservice.proto

2、通过proto文件生成代码

1) Go

2) Java

3、对应生成服务端和客户端

gRPC实战（一、快速开始）