java下使用gRPC的helloworld的demo实现

参考：

java下使用gRPC的helloworld的demo实现https://blog.csdn.net/u013992365/article/details/81698531#%E6%96%B0%E5%BB%BA%E4%B8%80%E4%B8%AA%E6%99%AE%E9%80%9A%E7%9A%84maven%E9%A1%B9%E7%9B%AE
grpc官方文档中文版 http://doc.oschina.net/grpc?t=58008
示例：https://github.com/grpc/grpc-java/tree/master/examples/src/main/java/io/grpc/examples

具体实施步骤：

1、新建一个普通的Maven项目：

点击下一步，再点击Finsh。

2、配置pom文件，导入grpc的依赖和插件

全部的pom内容如下：

<?xml version="1.0" encoding="UTF-8"?>
 
<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.grpcprojects</groupId>
 
<artifactId>grpcExercise3</artifactId>
 
<version>1.0-SNAPSHOT</version>
 
 
 
<properties>
 
<grpc-version>1.20.0</grpc-version>
 
</properties>
 
 
 
<dependencies>
 
<dependency>
 
<groupId>io.grpc</groupId>
 
<artifactId>grpc-core</artifactId>
 
<version>${grpc-version}</version>
 
</dependency>
 
<dependency>
 
<groupId>io.grpc</groupId>
 
<artifactId>grpc-netty-shaded</artifactId>
 
<version>${grpc-version}</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>
 
</dependencies>
 
 
 
<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:3.7.1:exe:${os.detected.classifier}</protocArtifact>
 
<pluginId>grpc-java</pluginId>
 
<pluginArtifact>io.grpc:protoc-gen-grpc-java:1.9.1:exe:${os.detected.classifier}</pluginArtifact>
 
<protoSourceRoot>src/main/proto</protoSourceRoot>
 
</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>
 
<version>3.6.1</version>
 
<configuration>
 
<source>1.8</source>
 
<target>1.8</target>
 
</configuration>
 
</plugin>
 
</plugins>
 
</build>
 
 
 
</project>

添加好依赖之后的显示：

添加之后选择右下键出现的import change，就能在Maven Projects中看到添加的依赖了。

3、编写helloworld.proto文件

在项目main目录下新建一个proto文件夹，再在此文件夹下创建一个helloworld.proto文件

helloworld.proto（跟官网上的一样）中的代码如下：

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;
 
}

重要的地方来了，编译helloworld.proto文件，编译此文件有两种方法，第一种使用protoc.exe和protoc-gen-grpc-java插件进行编译。第二种方法是用刚才在项目里边添加的插件进行编译。下边分别进行说明：

第一种：使用protoc.exe和protoc-gen-grpc-java插件进行编译

下载protoc.exe 工具，下载地址：https://github.com/protocolbuffers/protobuf/releases

下载protoc-gen-grpc 插件 , 下载地址: http://jcenter.bintray.com/io/grpc/protoc-gen-grpc-java/

将protoc.exe和protoc-gen-grpc插件放到main目录中：

在项目的terminal窗口中执行如下两条指令：

执行完每条指令之后，窗口应该不会出现任何信息，在项目文件目录中会添加如下文件：

第二种方法：用刚才在项目里边添加的插件进行编译

在分割线下边

4、添加客户端和服务端代码

我是直接从官网上直接拿过来的代码，分别为HelloWorldClient.java和HelloWorldServer.java

HelloWorldClient.java代码如下：

/*
 
* Copyright 2015 The gRPC Authors
 
*
 
* Licensed under the Apache License, Version 2.0 (the "License");
 
* you may not use this file except in compliance with the License.
 
* You may obtain a copy of the License at
 
*
 
* http://www.apache.org/licenses/LICENSE-2.0
 
*
 
* Unless required by applicable law or agreed to in writing, software
 
* distributed under the License is distributed on an "AS IS" BASIS,
 
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 
* See the License for the specific language governing permissions and
 
* limitations under the License.
 
*/
 
 
 
package helloworld;
 
 
 
import io.grpc.ManagedChannel;
 
import io.grpc.ManagedChannelBuilder;
 
import io.grpc.StatusRuntimeException;
 
import io.grpc.examples.helloworld.GreeterGrpc;
 
import io.grpc.examples.helloworld.HelloReply;
 
import io.grpc.examples.helloworld.HelloRequest;
 
 
 
import java.util.concurrent.TimeUnit;
 
import java.util.logging.Level;
 
import java.util.logging.Logger;
 
 
 
/**
 
* A simple client that requests a greeting from the {@link HelloWorldServer}.
 
*/
 
public class HelloWorldClient {
 
private static final Logger logger = Logger.getLogger(HelloWorldClient.class.getName());
 
 
 
private final ManagedChannel channel;
 
private final GreeterGrpc.GreeterBlockingStub blockingStub;
 
 
 
/** Construct client connecting to HelloWorld server at {@code host:port}. */
 
public HelloWorldClient(String host, int port) {
 
this(ManagedChannelBuilder.forAddress(host, port)
 
// Channels are secure by default (via SSL/TLS). For the example we disable TLS to avoid
 
// needing certificates.
 
.usePlaintext()
 
.build());
 
}
 
 
 
/** Construct client for accessing HelloWorld server using the existing channel. */
 
HelloWorldClient(ManagedChannel channel) {
 
this.channel = channel;
 
blockingStub = GreeterGrpc.newBlockingStub(channel);
 
}
 
 
 
public void shutdown() throws InterruptedException {
 
channel.shutdown().awaitTermination(5, TimeUnit.SECONDS);
 
}
 
 
 
/** Say hello to server. */
 
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());
 
}
 
 
 
/**
 
* Greet server. If provided, the first element of {@code args} is the name to use in the
 
* greeting.
 
*/
 
public static void main(String[] args) throws Exception {
 
HelloWorldClient client = new HelloWorldClient("localhost", 50051);
 
try {
 
/* Access a service running on the local machine on port 50051 */
 
String user = "world";
 
if (args.length > 0) {
 
user = args[0]; /* Use the arg as the name to greet if provided */
 
}
 
client.greet(user);
 
} finally {
 
client.shutdown();
 
}
 
}
 
}

HelloWorldServer.java代码如下：

/*
 
* Copyright 2015 The gRPC Authors
 
*
 
* Licensed under the Apache License, Version 2.0 (the "License");
 
* you may not use this file except in compliance with the License.
 
* You may obtain a copy of the License at
 
*
 
* http://www.apache.org/licenses/LICENSE-2.0
 
*
 
* Unless required by applicable law or agreed to in writing, software
 
* distributed under the License is distributed on an "AS IS" BASIS,
 
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 
* See the License for the specific language governing permissions and
 
* limitations under the License.
 
*/
 
 
 
package helloworld;
 
 
 
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 java.io.IOException;
 
import java.util.logging.Logger;
 
 
 
/**
 
* Server that manages startup/shutdown of a {@code Greeter} server.
 
*/
 
public class HelloWorldServer {
 
private static final Logger logger = Logger.getLogger(HelloWorldServer.class.getName());
 
 
 
private Server server;
 
 
 
private void start() throws IOException {
 
/* The port on which the server should run */
 
int port = 50051;
 
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() {
 
// Use stderr here since the logger may have been reset by its JVM shutdown hook.
 
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();
 
}
 
}
 
 
 
/**
 
* Await termination on the main thread since the grpc library uses daemon threads.
 
*/
 
private void blockUntilShutdown() throws InterruptedException {
 
if (server != null) {
 
server.awaitTermination();
 
}
 
}
 
 
 
/**
 
* Main launches the server from the command line.
 
*/
 
public static void main(String[] args) throws IOException, InterruptedException {
 
final HelloWorldServer server = new HelloWorldServer();
 
server.start();
 
server.blockUntilShutdown();
 
}
 
 
 
static 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();
 
}
 
}
 
}