• gRPC-Java实践


    1.新建一个Maven工程,添加gRPC相关依赖

            <!-- https://mvnrepository.com/artifact/io.grpc/grpc-stub -->
            <dependency>
                <groupId>io.grpc</groupId>
                <artifactId>grpc-all</artifactId>
                <version>1.20.0</version>
            </dependency>
    

    2.添加protocol buffers 编译插件

    <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.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
    
                <plugin>
                    <groupId>org.xolstice.maven.plugins</groupId>
                    <artifactId>protobuf-maven-plugin</artifactId>
                    <version>0.6.1</version>
                    <configuration>
                        <protocArtifact>com.google.protobuf:protoc:3.0.0:exe:${os.detected.classifier}</protocArtifact>
                        <pluginId>grpc-java</pluginId>
                        <pluginArtifact>io.grpc:protoc-gen-grpc-java:0.15.0:exe:${os.detected.classifier}</pluginArtifact>
                        <protocExecutable>/Users/sgf/Documents/yang/MyWork/protoc-3.7.1-osx-x86_64/bin/protoc</protocExecutable>
                    </configuration>
                    <executions>
                        <execution>
                            <goals>
                                <goal>compile</goal>
                                <goal>compile-custom</goal>
                            </goals>
                        </execution>
                    </executions>
                </plugin>
    
            </plugins>
        </build>
    

    2.1注意

    image.png

    第二个框框中的地址是我本地protoc的编译执行程序所在地址

    image.png

    可在此下载对应版本的编译执行程序

    这是我的文件结构,重要的文件都框出来了

    3.编写.proto文件

    syntax = "proto3";
    
    option java_multiple_files = true;
    option java_package = "com.page.awesome.dto.proto";
    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) {
        }
        // Sends another greeting
        rpc SayHelloAgain (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;
    }
    

    4.编译

    image.png
    图中的两个都需要,然后就完成了。
    image.png

    5.创建HelloWorldClient和HelloWorldServer

    /*
     * Copyright 2015 The gRPC Authors
     *
     * Licensed under the Apache License, Version 2.0 (the "License");
     * you may not use this file except in compliance with the License.
     * You may obtain a copy of the License at
     *
     *     http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    
    package com.page.awesome.hello;
    
    import com.page.awesome.dto.proto.GreeterGrpc;
    import com.page.awesome.dto.proto.HelloReply;
    import com.page.awesome.dto.proto.HelloRequest;
    import io.grpc.ManagedChannel;
    import io.grpc.ManagedChannelBuilder;
    import io.grpc.StatusRuntimeException;
    import java.util.concurrent.TimeUnit;
    import java.util.logging.Level;
    import java.util.logging.Logger;
    
    /**
     * A simple client that requests a greeting from the {@link HelloWorldServer}.
     */
    public class HelloWorldClient {
      private static final Logger logger = Logger.getLogger(HelloWorldClient.class.getName());
    
      private final ManagedChannel channel;
      private final GreeterGrpc.GreeterBlockingStub blockingStub;
    
      /** Construct client connecting to HelloWorld server at {@code host:port}. */
      public HelloWorldClient(String host, int port) {
        this(ManagedChannelBuilder.forAddress(host, port)
            // Channels are secure by default (via SSL/TLS). For the example we disable TLS to avoid
            // needing certificates.
            .usePlaintext()
            .build());
      }
    
      /** Construct client for accessing HelloWorld server using the existing channel. */
      HelloWorldClient(ManagedChannel channel) {
        this.channel = channel;
        blockingStub = GreeterGrpc.newBlockingStub(channel);
      }
    
      public void shutdown() throws InterruptedException {
        channel.shutdown().awaitTermination(5, TimeUnit.SECONDS);
      }
    
      /** Say hello to server. */
      public void greet(String name) {
        logger.info("client request ==============" + name + " ...");
        HelloRequest request = HelloRequest.newBuilder().setName(name).build();
        HelloReply response;
        try {
          response = blockingStub.sayHello(request);
        } catch (StatusRuntimeException e) {
          logger.log(Level.WARNING, "RPC failed: {0}", e.getStatus());
          return;
        }
        logger.info("response: ===============" + response.getMessage());
      }
    
      /**
       * Greet server. If provided, the first element of {@code args} is the name to use in the
       * greeting.
       */
      public static void main(String[] args) throws Exception {
        HelloWorldClient client = new HelloWorldClient("localhost", 50051);
        try {
          /* Access a service running on the local machine on port 50051 */
          String user = "world===============";
          if (args.length > 0) {
            user = args[0]; /* Use the arg as the name to greet if provided */
          }
          client.greet(user);
        } finally {
          client.shutdown();
        }
      }
    }
    
    /*
     * Copyright 2015 The gRPC Authors
     *
     * Licensed under the Apache License, Version 2.0 (the "License");
     * you may not use this file except in compliance with the License.
     * You may obtain a copy of the License at
     *
     *     http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    
    package com.page.awesome.hello;
    
    import com.page.awesome.dto.proto.GreeterGrpc;
    import com.page.awesome.dto.proto.HelloReply;
    import com.page.awesome.dto.proto.HelloRequest;
    import io.grpc.Server;
    import io.grpc.ServerBuilder;
    import io.grpc.stub.StreamObserver;
    import java.io.IOException;
    import java.util.logging.Logger;
    
    /**
     * Server that manages startup/shutdown of a {@code Greeter} server.
     */
    public class HelloWorldServer {
      private static final Logger logger = Logger.getLogger(HelloWorldServer.class.getName());
    
      private Server server;
    
      private void start() throws IOException {
        /* The port on which the server should run */
        int port = 50051;
        server = ServerBuilder.forPort(port)
            .addService(new GreeterImpl())
            .build()
            .start();
        logger.info("Server started, listening on " + port);
        Runtime.getRuntime().addShutdownHook(new Thread() {
          @Override
          public void run() {
            // Use stderr here since the logger may have been reset by its JVM shutdown hook.
            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();
        }
      }
    
      /**
       * 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 HelloWorldServer server = new HelloWorldServer();
        server.start();
        server.blockUntilShutdown();
      }
    
      static 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();
        }
      }
    }
    

    6.运行

    先运行HelloWorldServer,然后运行HelloWorldClient
    image.png

    image.png

    完成!

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  • 原文地址:https://www.cnblogs.com/fruitknife/p/10875536.html
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