gRPC示例初探【实战笔记】
目录
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>
备注：将上面例子中的helloworld.proto拷贝到该工程下，在编译时在target下自动生成相应的代码，将生成的代码拷贝到工程里，并将上面示例中的Client实现HelloWorldClient和Server端实现类HelloWorldServer拷贝到工程中。结构如下所示：
2.运行工程示例
Server运行
Client运行
四、小结
本文从官方给出的gRPC-java示例开始，从命令行和项目工程两种方式来运行Client向Server端调用示例，对gRPC有较直观的印象。
五、系列文章
】
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