gRPc实例

1.安装protocbuf

1. 下载protobuf window版

2. 配置环境变量：

   变量名：PROTOCBUF_HOME

变量值：D:\protoc-3.19.1-win64

找到系统变量中的path变量，选中后点击编辑，在新建的内容中输入：%PROTOBUF_HOME%\bin

3. idea安装protocbuf插件

2. gRPC项目构建

1. 插件

<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:3.17.3:exe:${os.detected.classifier}</protocArtifact>
        <pluginId>grpc-java</pluginId>
        <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.42.0:exe:${os.detected.classifier}</pluginArtifact>
      </configuration>
      <executions>
        <execution>
          <goals>
            <goal>compile</goal>
            <goal>compile-custom</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>

<dependency>
  <groupId>io.grpc</groupId>
  <artifactId>grpc-netty-shaded</artifactId>
  <version>1.42.0</version>
</dependency>
<dependency>
  <groupId>io.grpc</groupId>
  <artifactId>grpc-protobuf</artifactId>
  <version>1.42.0</version>
</dependency>
<dependency>
  <groupId>io.grpc</groupId>
  <artifactId>grpc-stub</artifactId>
  <version>1.42.0</version>
</dependency>
<dependency> <!-- necessary for Java 9+ -->
  <groupId>org.apache.tomcat</groupId>
  <artifactId>annotations-api</artifactId>
  <version>6.0.53</version>
  <scope>provided</scope>
</dependency>

2. 添加.proto文件

一定要在和src/main/java源文件目录同级的proto源文件目录才可以。

helloworld.proto

syntax = "proto3"; // 协议版本

// 选项配置
option java_package = "com.cgh.protobuf";
option java_outer_classname = "RPCDateServiceApi";
option java_multiple_files = true;

// 定义包名
package com.cgh.protobuf;

// 服务接口.定义请求参数和相应结果
service RPCDateService {
  rpc getDate (RPCDateRequest) returns (RPCDateResponse) {
  }
}

// 定义请求体
message RPCDateRequest {
  string userName = 1;
}

// 定义响应内容
message RPCDateResponse {
  string serverDate = 1;
}

3. 用插件根据.proto文件生成消息体类文件和XXXGrpc类文件

• mvn protobuf:compile 生成消息体类文件 （多次执行可能失败）
• mvn protobuf:compile-custom 生成XXXGrpc类文件 （多次执行可能失败)
• 把生成的消息体文件和 XXXGrpc 文件copy到项目

4. 编写实现类

import com.cgh.protobuf.RPCDateRequest;
import com.cgh.protobuf.RPCDateResponse;
import com.cgh.protobuf.RPCDateServiceGrpc;
import io.grpc.stub.StreamObserver;

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;

public class RPCDateServiceImpl extends RPCDateServiceGrpc.RPCDateServiceImplBase {

    @Override
    public void getDate(RPCDateRequest request, StreamObserver<RPCDateResponse> responseObserver) {
        //请求结果，我们定义的
        RPCDateResponse rpcDateResponse = null;
        //
        String userName = request.getUserName();
        String response = String.format("你好:%s,今天是%s.", userName, LocalDate.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
        try {
            // 定义响应,是一个builder构造器.
            rpcDateResponse = RPCDateResponse.newBuilder()
                    .setServerDate(response)
                    .build();
            //int i = 10/0;
        } catch (Exception e) {
            responseObserver.onError(e);
        } finally {

            responseObserver.onNext(rpcDateResponse);
        }

        responseObserver.onCompleted();
    }
}

5. 定义服务端

public class GRPCServer {
    private static final int port = 9999;

    public static void main(String[] args) throws IOException, InterruptedException {
        //设置service端口
        Server server = ServerBuilder.forPort(port)
                .addService(new RPCDateServiceImpl())
                .build().start();
        System.out.println(String.format("GRpc服务端启动成功, 端口号: %d.", port));

        server.awaitTermination();

    }
}

6. 定义客户端

private static final String host = "localhost";
    private static final int serverPort = 9999;
    public static void main(String[] args) {
        //1,拿到一个通信channel
        ManagedChannel channel = ManagedChannelBuilder.forAddress(host, serverPort).
                usePlaintext()//无需加密或认证
                .build();
        try {
            //2.拿到stub对象
            RPCDateServiceGrpc.RPCDateServiceBlockingStub rpcDateService  = RPCDateServiceGrpc.newBlockingStub(channel);
            RPCDateRequest rpcDateRequest = RPCDateRequest.newBuilder()
                    .setUserName("JACK")
                    .build();
            //3,请求
            RPCDateResponse rpcDateResponse = rpcDateService.getDate(rpcDateRequest);
            //4,输出结果
            System.out.println(rpcDateResponse.getServerDate());
        } finally {
            // 5.关闭channel, 释放资源.
            channel.shutdown();
        }

    }
}