《Netty学习打卡--从小白到放弃》----- 18 - netty 之grpc Bidirectional Streaming RPC 例子

打卡日期(2019-07-18)

学习要点

-   利用grpc完成Bidirectional Streaming RPC例子

步骤

• 1.配置grpc依赖包
• 2.编写proto文件
• 3.利用gradle generateProto生成java类
• 4.编写Server/Client服务
  注:应为服务端只负责启动，所以Server类复用上一章的
  《Netty学习打卡–从小白到放弃》----- 15 - netty 之grpc Simple RPC例子

2.编写proto文件

syntax = "proto3";


package study;

option java_package = "com.dragon.study";
option java_outer_classname = "Student";
option optimize_for = SPEED;
option java_multiple_files = true;

message StreamRequest{
    string message = 1;
}

message StreamResponse{
    string username = 1;
    string address = 2;
    int32 phone = 3;
}


service StudentService{
    rpc getAllUser(stream StreamRequest) returns (stream StreamResponse){}
}

3.利用gradle generateProto生成java类

运行命令:
gradle generateProto

4.编写Server/Client服务

Server

Server端跟上一章一样
《Netty学习打卡–从小白到放弃》----- 15 - netty 之grpc Simple RPC例子

package com.dragon.study.server;

import com.dragon.study.*;
import io.grpc.stub.StreamObserver;

import java.util.ArrayList;
import java.util.List;

public class StudentServiceImpl extends StudentServiceGrpc.StudentServiceImplBase {
    
    

     @Override
    public StreamObserver<StreamRequest> getAllUser(StreamObserver<StreamResponse> responseObserver) {
    
    
        StreamObserver<StreamRequest> streamObserver = new StreamObserver<StreamRequest>() {
    
    
            @Override
            public void onNext(StreamRequest value) {
    
    
                System.out.println("接收到客户端请求的参数 SreamRequest.message = " + value.getMessage());
                responseObserver.onNext(StreamResponse.newBuilder().setAddress("北京").setPhone(123).setUsername("王八犊子《"+value.getMessage()+"》").build());
            }

            @Override
            public void onError(Throwable t) {
    
    

            }

            @Override
            public void onCompleted() {
    
    
                responseObserver.onCompleted();
            }
        };

        return streamObserver;
    }

}

Client

package com.dragon.study.client;

import com.dragon.study.*;
import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;
import io.grpc.stub.StreamObserver;

import java.util.Iterator;
import java.util.concurrent.TimeUnit;
import java.util.logging.Logger;

public class StudentClient {
    
    
    private static final Logger logger = Logger.getLogger(StudentClient.class.getName());

    //channel相当于一个连接，客户端核心类
    private final ManagedChannel channel;
    //当请求是不是stream流的时候，使用阻塞式stub就可以
    private final StudentServiceGrpc.StudentServiceBlockingStub blockingStub;

    //需要指出一点，当请求是stream流的时候，就需要使用异步的请求方式去请求服务
    private final StudentServiceGrpc.StudentServiceStub stub;

    public StudentClient(String host , int port){
    
    
        //ManagedChannelBuilder 管理客户端的链接，用来创建链接
        this(ManagedChannelBuilder.forAddress(host,port).usePlaintext().build());
    }

    public StudentClient(ManagedChannel channel) {
    
    
        this.channel = channel;
        blockingStub = StudentServiceGrpc.newBlockingStub(channel);
        stub = StudentServiceGrpc.newStub(channel);
    }

    public void shutdown() throws InterruptedException {
    
    
        channel.shutdown().awaitTermination(100,TimeUnit.SECONDS);
    }

    public void getStreamUser(){
    
    
        StreamObserver<StreamRequest> requestStreamObserver = stub.getAllUser(new StreamObserver<StreamResponse>() {
    
    
            //收到服务器端的返回的结果
            @Override
            public void onNext(StreamResponse value) {
    
    
                System.out.println(value.getUsername() + "," + value.getAddress() + "," + value.getPhone());
            }

            @Override
            public void onError(Throwable t) {
    
    

            }

            @Override
            public void onCompleted() {
    
    

                System.out.println("conCompleted");

            }
        });
        requestStreamObserver.onNext(StreamRequest.newBuilder().setMessage("美美哒").build());
        requestStreamObserver.onCompleted();

    }

    public static void main(String[] args) throws InterruptedException {
    
    
        StudentClient client = new StudentClient("localhost",8080);
        try{
    
    
            client.getStreamUser();
        }finally {
    
    
            client.shutdown();
        }

    }

}

王八犊子《美美哒》,北京,123
conCompleted