使用说明
Triple 协议是 Dubbo3 的主要协议，完全兼容 gRPC over HTTP/2，并在协议级别扩展了负载均衡和流量控制相关机制。本文档旨在指导用户正确使用 Triple 协议。
在开始之前，您需要确定服务使用的序列化方法。如果是新服务，建议默认使用 protobuf 作为序列化方式，这样会有更好的性能和跨语言效果。如果原服务想升级协议，Triple 协议已经支持了其他的序列化方式，例如 Hessian / JSON 等。
Protobuf
编写 IDL 文件
syntax = "proto3"; option java_multiple_files = true; option java_package = "org.apache.dubbo.hello"; option java_outer_classname = "HelloWorldProto"; option objc_class_prefix = "HLW"; package helloworld; // The request message containing the user's name. message HelloRequest { string name = 1; } // The response message containing the greetings message HelloReply { string message = 1; }添加用于编译 protobuf 的扩展和插件（以 maven 为例）
<extensions> <extension> <groupId>kr.motd.maven</groupId> <artifactId>os-maven-plugin</artifactId> <version>1.6.1</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:3.7.1:exe:${os.detected.classifier}</protocArtifact> <pluginId>triple-java</pluginId> <outputDirectory>build/generated/source/proto/main/java</outputDirectory> </configuration> <executions> <execution> <goals> <goal>compile</goal> <goal>test-compile</goal> </goals> </execution> </executions> </plugin> </plugins>构建/编译以生成 protobuf 消息类
$ mvn clean install
单向模式
编写 Java 接口
import org.apache.dubbo.hello.HelloReply; import org.apache.dubbo.hello.HelloRequest; public interface IGreeter { /** * <pre> * Sends a greeting * </pre> */ HelloReply sayHello(HelloRequest request); }创建提供者
public static void main(String[] args) throws InterruptedException { ServiceConfig<IGreeter> service = new ServiceConfig<>(); service.setInterface(IGreeter.class); service.setRef(new IGreeter1Impl()); // Here you need to show that the protocol used by the declaration is triple service.setProtocol(new ProtocolConfig(CommonConstants.TRIPLE, 50051)); service.setApplication(new ApplicationConfig("demo-provider")); service.setRegistry(new RegistryConfig("zookeeper://127.0.0.1:2181")); service. export(); System.out.println("dubbo service started"); new CountDownLatch(1). await(); }创建消费者
public static void main(String[] args) throws IOException { ReferenceConfig<IGreeter> ref = new ReferenceConfig<>(); ref. setInterface(IGreeter. class); ref. setCheck(false); ref.setProtocol(CommonConstants.TRIPLE); ref. setLazy(true); ref. setTimeout(100000); ref. setApplication(new ApplicationConfig("demo-consumer")); ref.setRegistry(new RegistryConfig("zookeeper://127.0.0.1:2181")); final IGreeter iGreeter = ref. get(); System.out.println("dubbo ref started"); try { final HelloReply reply = iGreeter.sayHello(HelloRequest.newBuilder() .setName("name") .build()); TimeUnit. SECONDS. sleep(1); System.out.println("Reply:" + reply); } catch (Throwable t) { t. printStackTrace(); } System.in.read(); }运行提供者和消费者，您可以看到请求正常返回
回复：消息：“名称”
流模式
- 编写 Java 接口
import org.apache.dubbo.hello.HelloReply; import org.apache.dubbo.hello.HelloRequest; public interface IGreeter { /** * <pre> * Sends greeting by stream * </pre> */
StreamObserver
}
```
- 编写实现类
public class IStreamGreeterImpl implements IStreamGreeter {
@Override public StreamObserver
return new StreamObserver
@Override public void onNext(HelloRequest helloRequest) { System.out.println(“onNext 收到请求名称：” + helloRequest.getName()); replyList.add(HelloReply.newBuilder() .setMessage(“收到名称：” + helloRequest.getName()) .build()); }
@Override public void onError(Throwable cause) { System.out.println(“onError”); replyObserver.onError(cause); }
@Override public void onCompleted() { System.out.println(“onComplete 收到请求大小：” + replyList.size()); for (HelloReply reply : replyList) { replyObserver.onNext(reply); } replyObserver.onCompleted(); } }; } }
10. Create a Provider
```java
public class StreamProvider {
public static void main(String[] args) throws InterruptedException {
ServiceConfig<IStreamGreeter> service = new ServiceConfig<>();
service.setInterface(IStreamGreeter.class);
service.setRef(new IStreamGreeterImpl());
service.setProtocol(new ProtocolConfig(CommonConstants.TRIPLE, 50051));
service.setApplication(new ApplicationConfig("stream-provider"));
service.setRegistry(new RegistryConfig("zookeeper://127.0.0.1:2181"));
service. export();
System.out.println("dubbo service started");
new CountDownLatch(1). await();
}
}
创建消费者
public class StreamConsumer { public static void main(String[] args) throws InterruptedException, IOException { ReferenceConfig
System.out.println(“dubbo ref started”); try {
StreamObserver
@Override public void onError(Throwable throwable) { System.out.println(“onError:” + throwable.getMessage()); }
@Override public void onCompleted() { System.out.println(“onCompleted”); } });
streamObserver.onNext(HelloRequest.newBuilder() .setName(“tony”) .build());
streamObserver.onNext(HelloRequest.newBuilder() .setName(“nick”) .build());
streamObserver.onCompleted(); } catch (Throwable t) { t. printStackTrace(); } System.in.read(); } }
12. Run Provider and Consumer, you can see that the request returns normally
> onNext\
> receive name:tony\
> onNext\
> receive name:nick\
> onCompleted
### Other serialization methods
Omit steps 1-3 above, and specify the protocol used by Provider and Consumer to complete the protocol upgrade.
### Example program
The sample program of this article can be found in [triple-samples](https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/dubbo-samples-triple)
