java gRPC四种服务类型简单示例

时间：2023-03-09 09:35:57
java gRPC四种服务类型简单示例

一、gRPC 简介

gRPC 是Go实现的：一个高性能，开源，将移动和HTTP/2放在首位通用的RPC框架。使用gRPC可以在客户端调用不同机器上的服务端的方法，而客户端和服务端的开发语言和

运行环境可以有很多种，基本涵盖了主流语言和平台。双方交互的协议可以在proto文件中定义，客户端和服务端可以很方便的通过工具生成协议和代理代码。而消息的编码是采

用google protocol buffer，数据量小、速度快。

gRPC具有以下特点：

（1）基于 HTTP/2， 继而提供了连接多路复用、Body 和 Header 压缩等机制。可以节省带宽、降低TCP链接次数、节省CPU使用和延长电池寿命等。

（2）支持主流开发语言（C, C++, Python, PHP, Ruby, NodeJS, C#, Objective-C、Golang、Java）

（3）IDL (Interface Definition Language) 层使用了 Protocol Buffers, 非常适合团队的接口设计

二、编写示例工程

  • 下载安装protobuf，过程省略

  • 新建maven项目，过程省略，工程结构

    java gRPC四种服务类型简单示例

  • 完整的pom.xml

    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    
	<modelVersion>4.0.0</modelVersion>
    
	<groupId>com.gm</groupId>
    
	<artifactId>stream_grpc</artifactId>
    
	<version>0.0.1-SNAPSHOT</version>

	<name>stream_grpc</name>
    
	<url>http://maven.apache.org</url>

	<properties>
    
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    
	</properties>

	<dependencies>
    
		<dependency>
    
			<groupId>junit</groupId>
    
			<artifactId>junit</artifactId>
    
			<version>3.8.1</version>
    
			<scope>test</scope>
    
		</dependency>
    
		<dependency>
    
			<groupId>io.grpc</groupId>
    
			<artifactId>grpc-all</artifactId>
    
			<version>1.17.1</version>
    
		</dependency>
    
	</dependencies>

	<build>
    
		<extensions>
    
			<extension>
    
				<groupId>kr.motd.maven</groupId>
    
				<artifactId>os-maven-plugin</artifactId>
    
				<version>1.4.1.Final</version>
    
			</extension>
    
		</extensions>
    
		<plugins>
    
			<plugin>
    
				<groupId>org.xolstice.maven.plugins</groupId>
    
				<artifactId>protobuf-maven-plugin</artifactId>
    
				<version>0.5.0</version>
    
				<configuration>
    
					<!-- The version of protoc must match protobuf-java. If you don't depend
    
						on protobuf-java directly, you will be transitively depending on the protobuf-java
    
						version that grpc depends on. -->
    
					<protocArtifact>com.google.protobuf:protoc:3.0.0-beta-2:exe:${os.detected.classifier}</protocArtifact>
    
					<pluginId>grpc-java</pluginId>
    
					<pluginArtifact>io.grpc:protoc-gen-grpc-java:0.13.2:exe:${os.detected.classifier}</pluginArtifact>
    
					<protocExecutable>protoc.exe</protocExecutable>
    
				</configuration>
    
				<executions>
    
					<execution>
    
						<goals>
    
							<goal>compile</goal>
    
							<goal>compile-custom</goal>
    
						</goals>
    
					</execution>
    
				</executions>
    
			</plugin>
    
		</plugins>
    
	</build>
    
</project>

    此处需注意protoc的版本，我的为libprotoc 3.4.0，因此选择grpc-all 1.17.1版本

  • 编写 proto 文件

    在src/main目录下新建proto目录，新建stream.proto文件，文件可名称任意

    syntax = "proto3";
    
package stream;
    
service StreamService {
    
  //简单rpc
    
  rpc SimpleFun(RequestData) returns (ResponseData){}
    
  //服务器端流式rpc
    
  rpc ServerSideStreamFun(RequestData) returns (stream ResponseData){}
    
  //客户端流式rpc
    
  rpc ClientSideStreamFun(stream RequestData) returns (ResponseData){}
    
  //双向流式rpc
    
  rpc TwoWayStreamFun(stream RequestData) returns (stream ResponseData){}
    
}
    
message RequestData {
    
  string text = 1;
    
}

message ResponseData {
    
  string text = 1;
    
}

  • 编译 protobuf

    执行命令：mvn generate-sources在target目下生成下图的文件

    java gRPC四种服务类型简单示例

  • 文件复制

    在src/main/java目录下新建stream包，具体包取决于proto文件中的package名称 ，并java文件复制到新建包中

三、服务类型示例

gRPC存在四种服务类型：

简单rpc

就是一般的rpc调用，一个请求对象对应一个返回对象

  • proto语法，参考stream.proto文件： 
    //简单rpc
    
rpc SimpleFun(RequestData) returns (ResponseData){}
  • 服务实现 
    @Override
    
public void simpleFun(RequestData request, StreamObserver<ResponseData> responseObserver) {
    
	// TODO Auto-generated method stub
    
	System.out.println("请求参数：" + request.getText());
    
	responseObserver.onNext(ResponseData.newBuilder().setText("hello gRPC").build());
    
	responseObserver.onCompleted();
    
}
  • server实现，后三种服务类型server实现相同 
    package simple.fun;

import java.io.IOException;

import stream.ServiceImpl;
    
import stream.StreamServiceGrpc;
    
import stream.StreamServiceGrpc.StreamService;

public class Server {
    
	private static int port = 8883;
    
	private static io.grpc.Server server;

	public void run() {
    
		StreamService serviceImpl = new ServiceImpl();
    
		server = io.grpc.ServerBuilder.forPort(port).addService(StreamServiceGrpc.bindService(serviceImpl)).build();
    
		try {
    
			server.start();
    
			System.out.println("Server start success on port:" + port);
    
			server.awaitTermination();
    
		} catch (IOException e) {
    
			e.printStackTrace();
    
		} catch (InterruptedException e) {
    
			e.printStackTrace();
    
		}
    
	}

	public static void main(String[] args) {
    
		Server server = new Server();
    
		server.run();
    
	}
    
}
  • client实现 
    package simple.fun;

import java.io.FileNotFoundException;
    
import java.io.IOException;

import io.grpc.ManagedChannel;
    
import io.grpc.ManagedChannelBuilder;
    
import stream.Stream.RequestData;
    
import stream.Stream.ResponseData;
    
import stream.StreamServiceGrpc;
    
import stream.StreamServiceGrpc.StreamServiceBlockingStub;

public class Client {

	public static void main(String[] args) throws FileNotFoundException, IOException {
    
		ManagedChannel channel = ManagedChannelBuilder.forAddress("localhost", 8883).usePlaintext(true).build();
    
		StreamServiceBlockingStub stub = StreamServiceGrpc.newBlockingStub(channel);

		long start = System.currentTimeMillis();
    
		for (int i = 0; i < 10; i++) {
    
			RequestData requestData = RequestData.newBuilder().setText("hello world").build();
    
			ResponseData responseData = stub.simpleFun(requestData);
    
			System.out.println(responseData.getText());
    
		}
    
		System.out.println(System.currentTimeMillis() - start + " MS");
    
		channel.shutdown();
    
	}
    
}
  • 执行结果

    java gRPC四种服务类型简单示例java gRPC四种服务类型简单示例

服务端流式rpc

一个请求对象，服务端可以传回多个结果对象

  • proto语法，参考stream.proto文件： 
    //服务器端流式rpc
    
rpc ServerSideStreamFun(RequestData) returns (stream ResponseData){}
  • 服务实现 
    @Override
    
public void serverSideStreamFun(RequestData request, StreamObserver<ResponseData> responseObserver) {
    
	// TODO Auto-generated method stub
    
	System.out.println("请求参数：" + request.getText());
    
	for (int i = 0; i < 10; i++) {
    
		responseObserver.onNext(ResponseData.newBuilder().setText("你好" + i).build());
    
	}
    
	responseObserver.onCompleted();
    
}
  • client实现 
    package server.side.stream;

import java.io.FileNotFoundException;
    
import java.io.IOException;
    
import java.util.Iterator;

import io.grpc.ManagedChannel;
    
import io.grpc.ManagedChannelBuilder;
    
import stream.Stream.RequestData;
    
import stream.Stream.ResponseData;
    
import stream.StreamServiceGrpc;
    
import stream.StreamServiceGrpc.StreamServiceBlockingStub;

public class Client {

	public static void main(String[] args) throws FileNotFoundException, IOException {
    
		RequestData requestData = RequestData.newBuilder().setText("hello world").build();
    
		ManagedChannel channel = ManagedChannelBuilder.forAddress("localhost", 8883).usePlaintext(true).build();
    
		StreamServiceBlockingStub stub = StreamServiceGrpc.newBlockingStub(channel);

		Iterator<ResponseData> it = stub.serverSideStreamFun(requestData);
    
		long start = System.currentTimeMillis();
    
		while (it.hasNext()) {
    
			System.out.println(it.next().getText());
    
		}
    
		channel.shutdown();
    
		System.out.println(System.currentTimeMillis() - start + " MS");

	}
    
}
  • 执行结果

    -java gRPC四种服务类型简单示例java gRPC四种服务类型简单示例

客户端流式rpc

客户端传入多个请求对象，服务端返回一个响应结果

  • proto语法，参考stream.proto文件： 
    //客户端流式rpc
    
rpc ClientSideStreamFun(stream RequestData) returns (ResponseData){}
  • 服务实现 
    @Override
    
public StreamObserver<RequestData> clientSideStreamFun(StreamObserver<ResponseData> responseObserver) {
    
	// TODO Auto-generated method stub
    
	return new StreamObserver<RequestData>() {
    
		private ResponseData.Builder builder = ResponseData.newBuilder();

		@Override
    
		public void onNext(RequestData value) {
    
			// TODO Auto-generated method stub
    
			System.out.println("请求参数：" + value.getText());

		}

		@Override
    
		public void onError(Throwable t) {
    
			// TODO Auto-generated method stub

		}

		@Override
    
		public void onCompleted() {
    
			// TODO Auto-generated method stub
    
			builder.setText("数据接收完成");
    
			responseObserver.onNext(builder.build());
    
			responseObserver.onCompleted();
    
		}

	};
    
}
  • client实现 
    package client.side.stream;

import java.io.FileNotFoundException;
    
import java.io.IOException;
    
import java.util.Iterator;

import io.grpc.ManagedChannel;
    
import io.grpc.ManagedChannelBuilder;
    
import io.grpc.stub.StreamObserver;
    
import stream.Stream.RequestData;
    
import stream.Stream.ResponseData;
    
import stream.StreamServiceGrpc;
    
import stream.StreamServiceGrpc.StreamServiceBlockingStub;
    
import stream.StreamServiceGrpc.StreamServiceStub;

public class Client {

	public static void main(String[] args) throws FileNotFoundException, IOException, InterruptedException {
    
		ManagedChannel channel = ManagedChannelBuilder.forAddress("localhost", 8883).usePlaintext(true).build();
    
		StreamServiceStub asyncStub = StreamServiceGrpc.newStub(channel);

		StreamObserver<ResponseData> responseData = new StreamObserver<ResponseData>() {
    
			@Override
    
			public void onNext(ResponseData value) {
    
				// TODO Auto-generated method stub
    
				System.out.println(value.getText());
    
			}

			@Override
    
			public void onError(Throwable t) {
    
				// TODO Auto-generated method stub
    
				t.printStackTrace();
    
			}

			@Override
    
			public void onCompleted() {
    
				// TODO Auto-generated method stub
    
				// 关闭channel
    
				channel.shutdown();
    
			}
    
		};

		StreamObserver<RequestData> requestData = asyncStub.clientSideStreamFun(responseData);
    
		long start = System.currentTimeMillis();
    
		for (int i = 0; i < 10; i++) {
    
			requestData.onNext(RequestData.newBuilder().setText("你好" + i).build());
    
		}
    
		requestData.onCompleted();
    
		System.out.println(System.currentTimeMillis() - start + " MS");
    
		// 由于是异步获得结果，所以sleep 10秒
    
		Thread.sleep(10000);
    
	}
    
}
  • 执行结果

    java gRPC四种服务类型简单示例java gRPC四种服务类型简单示例

双向流式rpc

结合客户端流式rpc和服务端流式rpc，可以传入多个对象，返回多个响应对象

  • proto语法，参考stream.proto文件： 
    //双向流式rpc
    
rpc TwoWayStreamFun(stream RequestData) returns (stream ResponseData){}
  • 服务实现 
    	@Override
    
public StreamObserver<RequestData> twoWayStreamFun(StreamObserver<ResponseData> responseObserver) {
    
	// TODO Auto-generated method stub
    
	return new StreamObserver<RequestData>() {

		@Override
    
		public void onNext(RequestData value) {
    
			// TODO Auto-generated method stub
    
			System.out.println("请求参数：" + value.getText());
    
			responseObserver.onNext(ResponseData.newBuilder().setText(value.getText() + "，欢迎你的加入").build());
    
		}

		@Override
    
		public void onError(Throwable t) {
    
			// TODO Auto-generated method stub
    
			t.printStackTrace();
    
		}

		@Override
    
		public void onCompleted() {
    
			// TODO Auto-generated method stub
    
			responseObserver.onCompleted();
    
		}

	};
    
}
  • client实现 
    package two.way.stream;

import java.io.FileNotFoundException;
    
import java.io.IOException;
    
import java.util.Iterator;

import io.grpc.ManagedChannel;
    
import io.grpc.ManagedChannelBuilder;
    
import io.grpc.stub.StreamObserver;
    
import stream.Stream.RequestData;
    
import stream.Stream.ResponseData;
    
import stream.StreamServiceGrpc;
    
import stream.StreamServiceGrpc.StreamServiceBlockingStub;
    
import stream.StreamServiceGrpc.StreamServiceStub;

public class Client {

	public static void main(String[] args) throws FileNotFoundException, IOException, InterruptedException {
    
		ManagedChannel channel = ManagedChannelBuilder.forAddress("localhost", 8883).usePlaintext(true).build();
    
		StreamServiceStub asyncStub = StreamServiceGrpc.newStub(channel);

		StreamObserver<ResponseData> responseData = new StreamObserver<ResponseData>() {
    
			@Override
    
			public void onNext(ResponseData value) {
    
				// TODO Auto-generated method stub
    
				System.out.println(value.getText());
    
			}

			@Override
    
			public void onError(Throwable t) {
    
				// TODO Auto-generated method stub
    
				t.printStackTrace();
    
			}

			@Override
    
			public void onCompleted() {
    
				// TODO Auto-generated method stub
    
				// 关闭channel
    
				channel.shutdown();
    
			}
    
		};

		StreamObserver<RequestData> requestData = asyncStub.twoWayStreamFun(responseData);
    
		long start = System.currentTimeMillis();
    
		for (int i = 0; i < 10; i++) {
    
			requestData.onNext(RequestData.newBuilder().setText("你好" + i).build());
    
		}
    
		requestData.onCompleted();
    
		System.out.println(System.currentTimeMillis() - start + " MS");
    
		// 由于是异步获得结果，所以sleep 10秒
    
		Thread.sleep(10000);
    
	}
    
}
  • 执行结果

    java gRPC四种服务类型简单示例java gRPC四种服务类型简单示例
  • 完整代码

    https://github.com/gm19900510/stream_grpc_java

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