java本地实现grpc调用的小demo

参考了下grpc的官方demo，但是它的代码有点多，我精简了些，做个实现helloworld的小项目

git地址：https://github.com/BAIBING666/baibingGrpcDemo.git

pom文件引入相关依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>baibingGrpcDemo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>11</maven.compiler.source>
        <maven.compiler.target>11</maven.compiler.target>
        <grpc.version>1.14.0</grpc.version>
    </properties>
        <dependencies>
            <!-- grpc libs -->
            <dependency>
                <groupId>io.grpc</groupId>
                <artifactId>grpc-netty</artifactId>
                <version>${grpc.version}</version>
            </dependency>
            <dependency>
                <groupId>io.grpc</groupId>
                <artifactId>grpc-context</artifactId>
                <version>${grpc.version}</version>
            </dependency>
            <dependency>
                <groupId>io.grpc</groupId>
                <artifactId>grpc-protobuf</artifactId>
                <version>${grpc.version}</version>
            </dependency>
            <dependency>
                <groupId>io.grpc</groupId>
                <artifactId>grpc-stub</artifactId>
                <version>${grpc.version}</version>
            </dependency>
            <dependency>
                <groupId>io.grpc</groupId>
                <artifactId>grpc-services</artifactId>
                <version>${grpc.version}</version>
            </dependency>
            <dependency>
                <groupId>javax.annotation</groupId>
                <artifactId>javax.annotation-api</artifactId>
                <version>1.2</version>
            </dependency>
            <dependency>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-api</artifactId>
                <version>1.7.25</version>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>RELEASE</version>
                <scope>compile</scope>
            </dependency>


        </dependencies>
    <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>0.5.0</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>


</project>

编写helloworld.proto

syntax = "proto3";

option java_multiple_files = true;


package helloworld;

// 问好类
service Greeter {
  // 问候方法
  rpc SayHello (HelloRequest) returns (HelloReply);
}

// 请求类
message HelloRequest {
  string name = 1;
}

// 回应类
message HelloReply {
  string message = 1;
}

grpc会根据你编写的proto编译生成一些东西：

编译完成后我们就可以来写client类和server类

client类：

package client;

import helloworld.GreeterGrpc;
import helloworld.HelloReply;
import helloworld.HelloRequest;
import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;
import io.grpc.StatusRuntimeException;


import java.util.concurrent.TimeUnit;

/**
 * @program: baibingGrpcDemo
 * @description:
 * @author: bing.bai
 * @create: 2021-08-17 10:21
 */

public class HelloWorldClient {

  private final ManagedChannel channel;
  private final GreeterGrpc.GreeterBlockingStub blockingStub;

  public HelloWorldClient(String host, int port) {
    channel = ManagedChannelBuilder.forAddress(host, port).usePlaintext(true).build();

    blockingStub = GreeterGrpc.newBlockingStub(channel);
  }

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

  public void greet(String name) {
    HelloRequest request = HelloRequest.newBuilder().setName(name).build();
    HelloReply response;
    try {
      response = blockingStub.sayHello(request);
    } catch (StatusRuntimeException e) {
      System.out.println("RPC failed: {0}");
      return;
    }
    System.out.println(("Message from gRPC-Server: " + response.getMessage()));
  }

  public static void main(String[] args) throws InterruptedException {
    HelloWorldClient client = new HelloWorldClient("127.0.0.1", 50051);
    try {
      String user = "world";
      client.greet(user);
    } finally {
      client.shutdown();
    }
  }
}

server类：

package server;

import helloworld.GreeterGrpc;
import helloworld.HelloReply;
import helloworld.HelloRequest;
import io.grpc.Server;
import io.grpc.ServerBuilder;

import io.grpc.stub.StreamObserver;


import java.io.IOException;

/**
 * @program: baibingGrpcDemo
 * @description:
 * @author: bing.bai
 * @create: 2021-08-17 10:40
 */

public class HelloWorldServer {
  private int port = 50051;
  private Server server;

  private void start() throws IOException {
    server = ServerBuilder.forPort(port).addService(new GreeterImpl()).build().start();
    System.out.println("服务启动");
    Runtime.getRuntime()
        .addShutdownHook(
            new Thread() {

              @Override
              public void run() {

                System.err.println("*** shutting down gRPC server since JVM is shutting down");
                HelloWorldServer.this.stop();
                System.err.println("*** server shut down");

              }
            });
  }

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

  // block 一直到退出程序
  private void blockUntilShutdown() throws InterruptedException {
    if (server != null) {
      server.awaitTermination();
    }
  }

  public static void main(String[] args) throws IOException, InterruptedException {

    final HelloWorldServer server = new HelloWorldServer();
    server.start();
    server.blockUntilShutdown();
  }

  // 实现 定义一个实现服务接口的类
  private class GreeterImpl extends GreeterGrpc.GreeterImplBase {
    @Override
    public void sayHello(HelloRequest req, StreamObserver<HelloReply> responseObserver) {
      HelloReply reply = HelloReply.newBuilder().setMessage(("Hello " + req.getName())).build();
      responseObserver.onNext(reply);
      responseObserver.onCompleted();
      System.out.println("Message from gRPC-Client:" + req.getName());
    }
  }
}

运行结果：