grpc ---- 运行
关于grpc的定义，就不叙述了，因为百度上面太多了。
但还是要说一句：gRPC是一个高性能、开源和通用的RPC(远程过程调用协议)框架
现在上代码，就是一个简单的列子，仿照官网和一些博客上面
开发工具：IDEA，maven构建
项目结构，proto，java这两个文件夹当成空的来看
1：maven文件配置：
三个重要的jar包
<?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.ming</groupId>
<artifactId>grpc_demo</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>grpc_demo Maven Webapp</name>
<!-- FIXME change it to the project's website -->
<url>http://www.example.com</url>
<properties>
<grpc.version>1.0.3</grpc.version>
</properties>
<dependencies>
<dependency>
<groupId>io.grpc</groupId>
<artifactId>grpc-netty</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>${grpc.version}</version>
</dependency>
</dependencies>
<build>
<extensions>
<extension>
<groupId>kr.motd.maven</groupId>
<artifactId>os-maven-plugin</artifactId>
<version>1.4.1.Final</version>
</extension>
</extensions>
<plugins>
<plugin>
<groupId>org.xolstice.maven.plugins</groupId>
<artifactId>protobuf-maven-plugin</artifactId>
<version>0.5.0</version>
<configuration>
<protocArtifact>com.google.protobuf:protoc:3.1.0:exe:${os.detected.classifier}</protocArtifact>
<pluginId>grpc-java</pluginId>
<pluginArtifact>io.grpc:protoc-gen-grpc-java:${grpc.version}:exe:${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>1.6</source>
<target>1.6</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
2：我们在proto文件夹下创建一个hello.proto
// 指定格式
syntax = "proto3";
//一些生成代码的设置
option java_multiple_files = true;
option java_package = "com.ming.helloworld";
option java_outer_classname = "HelloWorldProto";
option objc_class_prefix = "HLW";
package helloworld;
// 定义了一个 service
service Greeter {
// 发送一个greeting
rpc SayHello (HelloRequest) returns (HelloReply) {
}
}
// 定义一个消息请求体
message HelloRequest {
string name = 1;
}
// 定义一个消息回复体
message HelloReply {
string message = 1;
}
3：生成代码
然后我们就会发现这个
现在我们开始编写服务端和客户端的代码：
客户端：HelloWorldClient.java
import com.ming.helloworld.HelloReply;
import com.ming.helloworld.HelloRequest;
import io.grpc.ManagedChannel;
import io.grpc.ManagedChannelBuilder;
import io.grpc.StatusRuntimeException;
import com.ming.helloworld.GreeterGrpc;
import java.util.Scanner;
import java.util.concurrent.TimeUnit;
/**
* 客户端
* @author MING
* @date 2018/10/28 2:38
*/
public class HelloWorldClient {
private final ManagedChannel channel; //一个gRPC信道
private final GreeterGrpc.GreeterBlockingStub blockingStub;//阻塞/同步 存根
//初始化信道和存根
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(true));
}
/** Construct client for accessing RouteGuide server using the existing channel. */
private HelloWorldClient(ManagedChannelBuilder<?> channelBuilder) {
channel = channelBuilder.build();
blockingStub = GreeterGrpc.newBlockingStub(channel);
}
public void shutdown() throws InterruptedException {
channel.shutdown().awaitTermination(5, TimeUnit.SECONDS);
}
//客户端方法
public void greet(String name){
HelloRequest request = HelloRequest.newBuilder().setName(name).build();
HelloReply response;
try {
response = blockingStub.sayHello(request);
} catch (StatusRuntimeException e) {
System.out.println("RPC调用失败:"+e.getMessage());
return;
}
System.out.println("服务器返回信息:"+response.getMessage());
}
public static void main(String[] args) throws InterruptedException {
HelloWorldClient client = new HelloWorldClient("127.0.0.1",50051);
try {
Scanner sc = new Scanner(System.in);
String next = sc.next();
client.greet("world:"+next);
}finally {
client.shutdown();
}
}
}
服务端：HelloWorldServer.java
import com.ming.helloworld.GreeterGrpc;
import com.ming.helloworld.HelloReply;
import com.ming.helloworld.HelloRequest;
import io.grpc.Server;
import io.grpc.ServerBuilder;
import io.grpc.stub.StreamObserver;
import java.io.IOException;
/**
* 服务端
* @author MING
* @date 2018/10/28 2:36
*/
public class HelloWorldServer {
private int port = 50051;
private Server server;
/**
* 启动服务
* @throws IOException
*/
private void start() throws IOException {
server = ServerBuilder.forPort(port)
.addService(new GreeterImpl())
.build()
.start();
System.out.println("service start...");
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();
}
}
public static void main(String[] args) throws IOException, InterruptedException {
final HelloWorldServer server = new HelloWorldServer();
server.start();
server.blockUntilShutdown();
}
// 实现 定义一个实现服务接口的类
private class GreeterImpl extends GreeterGrpc.GreeterImplBase {
public void sayHello(HelloRequest req, StreamObserver<HelloReply> responseObserver) {
//获取参数
System.out.println("收到的信息:"+req.getName());
//这里可以放置具体业务处理代码 start
//这里可以放置具体业务处理代码 end
//构造返回
HelloReply reply = HelloReply.newBuilder().setMessage(("Hello: " + req.getName())).build();
responseObserver.onNext(reply);
responseObserver.onCompleted();
}
}
}
最后项目结构：
然后运行看下效果：先运行服务端
IDEA 需要下载支持proto的插件
总体感觉起来，不是太难，但是现在就会发现一个问题，就是基于这个小demo为什么跑成功了？
https://www.jianshu.com/p/46d600e5a1b1这篇文章中就会有详细的说明