java使用gRPC框架

2016-06-10

tonglin0325

1.定义proto文件
2.编译proto文件
1. 1.使用protoc命令编译
2. 2.使用maven插件编译
3.编写server和client

官方文档

1 2	https://grpc.io/docs/languages/java/quickstart/

官方example

1 2	https://github.com/grpc/grpc-java

1.定义proto文件#

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;
}

proto定义，参考官方文档

1 2	https://github.com/grpc/grpc-java/blob/master/examples/src/main/proto/helloworld.proto

2.编译proto文件#

1.使用protoc命令编译#

在项目目录下运行编译命令，里面使用了protoc-gen-grpc-java执行文件，需要参考：编译grpc-java项目生成protoc-gen-grpc-java文件

1 2	protoc --plugin=protoc-gen-grpc-java=./protoc-gen-grpc-java -I=./ --java_out=./src/main/java/ --grpc-java_out=./src/main/java/ ./src/main/proto/helloworld.proto

得到proto文件中定义的model和service的java代码

2.使用maven插件编译#

当然也可以使用maven插件来生成proto model和service的java代码，需要在pom.xml中添加插件，如下

<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>0.5.1</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>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>8</source>
                <target>8</target>
            </configuration>
        </plugin>

    </plugins>
</build>

然后点击protobuf:compile和protobuf:comile-custome即可，参考：idea中.proto文件生成model类和service类

target目录下就会生成java代码

3.编写server和client#

1.添加依赖#

<!-- log4j -->
<dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>1.2.17</version>
</dependency>
<!--google-->
<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>31.1-jre</version>
</dependency>
<!--grpc-->
<dependency>
    <groupId>io.grpc</groupId>
    <artifactId>grpc-netty-shaded</artifactId>
    <version>1.59.0</version>
</dependency>
<dependency>
    <groupId>io.grpc</groupId>
    <artifactId>grpc-protobuf</artifactId>
    <version>1.59.0</version>
</dependency>
<dependency>
    <groupId>io.grpc</groupId>
    <artifactId>grpc-stub</artifactId>
    <version>1.59.0</version>
</dependency>

2.server代码#

官方例子

1 2	https://github.com/grpc/grpc-java/blob/master/examples/src/main/java/io/grpc/examples/helloworld/HelloWorldServer.java

package com.interview.rpc;

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 org.apache.log4j.Logger;

import java.io.IOException;

public class HelloWorldServer {

    private static final Logger logger = Logger.getLogger(HelloWorldServer.class.getName());

    private int port = 50051;
    private Server server;

    public static void main(String[] args) throws IOException, InterruptedException {
        final HelloWorldServer server = new HelloWorldServer();
        server.start();
        server.blockUntilShutdown();
    }

    private void start() throws IOException {
        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() {

                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();
        }
    }

    // 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());
            System.out.println("Message Response:" + reply.getMessage());
        }
    }

}

3.client代码#