gRPC示例初探实战笔记

Posted 2021-04-11 瓜农老梁

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一、运行示例代码 1.下载源代码 2.编译Client和Server 3.运行Server 4.运行Client 二、增加方法示例 1.proto在中增加SayHelloAgain方法 2.Server端实现sayHelloAgain方法 3.Client端增加调用方法 4.运行示例三、Maven项目中运行示例 1.添加依赖和proto生成代码插件 2.运行工程示例

四、小结

五、系列文章

一、运行示例代码

1.下载源代码

git clone -b v1.25.0 https://github.com/grpc/grpc-java
cd grpc-java/examples

2.编译Client和Server

./gradlew installDist

BUILD SUCCESSFUL in 1s
14 actionable tasks: 9 executed, 5 up-to-date

3.运行Server

./build/install/examples/bin/hello-world-server
十一月 10, 2019 3:55:16 下午 io.grpc.examples.helloworld.HelloWorldServer start
信息: Server started, listening on 50051

4.运行Client

./build/install/examples/bin/hello-world-client
十一月 10, 2019 4:05:00 下午 io.grpc.examples.helloworld.HelloWorldClient greet
信息: Will try to greet world ...
十一月 10, 2019 4:05:01 下午 io.grpc.examples.helloworld.HelloWorldClient greet
信息: Greeting: Hello world

备注：Will try to greet world ...这条日志在Client端访问Server前打印；Greeting: Hello world 这条日志在Server返回给Client后打印。

二、增加方法示例

1.proto在中增加SayHelloAgain方法

代码位置：src/main/proto/helloworld.proto

// 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;
}

编译后会在GreeterImplBase类中生成sayHelloAgain方法内容如下：

public void sayHelloAgain(io.grpc.examples.helloworld.HelloRequest request,
        io.grpc.stub.StreamObserver<io.grpc.examples.helloworld.HelloReply> responseObserver) {
      asyncUnimplementedUnaryCall(getSayHelloAgainMethod(), responseObserver);
}

2.Server端实现sayHelloAgain方法

代码位置：

src/main/java/io/grpc/examples/helloworld/HelloWorldServer.java

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();
  }

  @Override
  public void sayHelloAgain(HelloRequest req, StreamObserver<HelloReply> responseObserver) {
    HelloReply reply = HelloReply.newBuilder().setMessage("Hello again " + req.getName()).build();
    responseObserver.onNext(reply);
    responseObserver.onCompleted();
  }
}

3.Client端增加调用方法

代码位置：src/main/java/io/grpc/examples/helloworld/HelloWorldClient.java

public void greet(String name) {
  logger.info("Will try to greet " + 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("Greeting: " + response.getMessage());
  try {
    response = blockingStub.sayHelloAgain(request);
  } catch (StatusRuntimeException e) {
    logger.log(Level.WARNING, "RPC failed: {0}", e.getStatus());
    return;
  }
  logger.info("Greeting: " + response.getMessage());
}

4.运行示例

编译Client和Server

./gradlew installDist

> Task :compileJava
警告: [options] 未与 -source 1.7 一起设置引导类路径
1 个警告

BUILD SUCCESSFUL in 1s
14 actionable tasks: 3 executed, 11 up-to-date

运行Server

./build/install/examples/bin/hello-world-server
十一月 10, 2019 4:53:53 下午 io.grpc.examples.helloworld.HelloWorldServer start
信息: Server started, listening on 50051

运行Client

./build/install/examples/bin/hello-world-client
十一月 10, 2019 4:53:56 下午 io.grpc.examples.helloworld.HelloWorldClient greet
信息: Will try to greet world ...
十一月 10, 2019 4:53:57 下午 io.grpc.examples.helloworld.HelloWorldClient greet
信息: Greeting: Hello world
十一月 10, 2019 4:53:57 下午 io.grpc.examples.helloworld.HelloWorldClient greet
信息: Greeting: Hello again world

Server端新增的SayHelloAgain被执行，返回给客户端并打印。

三、Maven项目中运行示例

1.添加依赖和proto生成代码插件

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
    <grpc.version>1.25.0</grpc.version><!-- CURRENT_GRPC_VERSION -->
    <protobuf.version>3.10.0</protobuf.version>
    <protoc.version>3.10.0</protoc.version>
</properties>

 <dependency>
    <groupId>io.grpc</groupId>
    <artifactId>grpc-netty-shaded</artifactId>
    <version>1.25.0</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>com.google.protobuf</groupId>
    <artifactId>protobuf-java-util</artifactId>
    <version>${protobuf.version}</version>
</dependency>

<build>
    <extensions>
        <extension>
            <groupId>kr.motd.maven</groupId>
            <artifactId>os-maven-plugin</artifactId>
            <version>1.6.2</version>
        </extension>
    </extensions>
    <plugins>
        <plugin>
            <groupId>org.xolstice.maven.plugins</groupId>
            <artifactId>protobuf-maven-plugin</artifactId>
            <version>0.6.1</version>
            <configuration>
                <protocArtifact>com.google.protobuf:protoc:${protoc.version}:exe:${os.detected.classifier}</protocArtifact>
                <pluginId>grpc-java</pluginId>
                <pluginArtifact>io.grpc:protoc-gen-grpc-java:${grpc.version}:exe:${os.detected.classifier}</pluginArtifact>
            </configuration>
            <executions>
                <execution>
                    <goals>
                        <goal>compile</goal>
                        <goal>compile-custom</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>6</source>
                <target>6</target>
            </configuration>
        </plugin>
    </plugins>
</build>