grpc java helloworld 简单demo实现

写在前面

最近google发布了grpc1.0，之前一直关注过grpc，数据交互使用了protocol buffer,相比之前使用的hession和json序列化方式性能应该提升不少，所有先搞一个grpc的hello world跑一下,项目使用maven搭建，并使用idea开发。

使用idea创建maven项目，添加pom配置

添加grpc1.0 maven依赖

<dependency>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-netty</artifactId>
            <version>1.0.0</version>
        </dependency>
        <dependency>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-protobuf</artifactId>
            <version>1.0.0</version>
        </dependency>
        <dependency>
            <groupId>io.grpc</groupId>
            <artifactId>grpc-stub</artifactId>
            <version>1.0.0</version>
        </dependency>

配置protobuf maven插件

配置了protobuf 插件后，可以自动将.proto文件生成对应的java代码

<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:3.0.0:exe:${os.detected.classifier}</protocArtifact>
                    <pluginId>grpc-java</pluginId>
                    <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.0.0:exe:${os.detected.classifier}</pluginArtifact>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>compile</goal>
                            <goal>compile-custom</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

编写proto文件 helloworld.proto

syntax = "proto3";

option java_multiple_files = true;
option java_package = "io.grpc.examples.helloworld";
option java_outer_classname = "HelloWorldProto";
option objc_class_prefix = "HLW";

package helloworld;

// The greeting service definition.
service Greeter {
  // Sends a greeting
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string message = 1;
}

编写grpc 服务端HelloWorldServer.java

package com;

import io.grpc.Server;
import io.grpc.ServerBuilder;
import io.grpc.examples.helloworld.GreeterGrpc;
import io.grpc.examples.helloworld.HelloReply;
import io.grpc.examples.helloworld.HelloRequest;
import io.grpc.stub.StreamObserver;

import java.io.IOException;

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("service start...");

        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 {


        public void sayHello(HelloRequest req, StreamObserver<HelloReply> responseObserver) {
            System.out.println("service:"+req.getName());
            HelloReply reply = HelloReply.newBuilder().setMessage(("Hello: " + req.getName())).build();
            responseObserver.onNext(reply);
            responseObserver.onCompleted();
        }
    }
}

编写grpc 客户端 HelloWorldClient.java

package com;

import io.grpc.ManagedChannel; 
import io.grpc.ManagedChannelBuilder;
import io.grpc.examples.helloworld.GreeterGrpc; 
import io.grpc.examples.helloworld.HelloReply; 
import io.grpc.examples.helloworld.HelloRequest;
import java.util.concurrent.TimeUnit; 


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 = blockingStub.sayHello(request);
        System.out.println(response.getMessage());

    }

    public static void main(String[] args) throws InterruptedException { 
        HelloWorldClient client = new HelloWorldClient("127.0.0.1",50051);
        for(int i=0;i<5;i++){
            client.greet("world:"+i);
        }


    } 
}

项目完整结构

项目运行结果

服务端

客户端