使用 IDL 定義跨語言服務

從零開始的 Demo，示範如何基於 IDL 定義 Dubbo 服務並使用 Triple 協定

使用 IDL 定義服務具有更好的跨語言友善性。對於 Dubbo3 的新使用者，我們推薦這種方法。然而，Triple 協定並非與 IDL 強綁定。您也可以使用 Java 介面 + Pojo 來定義服務並啟用 Triple 協定。詳情請參閱範例。

更多 Triple 和 IDL 的用法，請參考官方範例

先決條件

JDK 版本 >= 8
已安裝 Maven

建立專案

首先建立一個空的 Maven 專案

$ mvn archetype:generate \
    -DgroupId=org.apache.dubbo \
    -DartifactId=tri-stub-demo \
    -DarchetypeArtifactId=maven-archetype-quickstart \
    -DarchetypeVersion=1.4 \
    -DarchetypeGroupId=org.apache.maven.archetypes \
    -Dversion=1.0-SNAPSHOT

切換到專案目錄
```
$ cd tri-stub-demo
```

在 pom.xml 中設定 JDK 版本，新增 Dubbo 相依性和外掛程式

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <dubbo.version>3.1.7</dubbo.version>
</properties>

<dependencies>
   <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
       <version>4.13</version>
       <scope>test</scope>
   </dependency>
   <dependency>
       <groupId>org.apache.dubbo</groupId>
       <artifactId>dubbo</artifactId>
       <version>${dubbo.version}</version>
   </dependency>
   <dependency>
    <groupId>org.apache.dubbo</groupId>
    <artifactId>dubbo-dependencies-zookeeper-curator5</artifactId>
    <type>pom</type>
    <version>${dubbo.version}</version>
   </dependency>
    <dependency>
        <groupId>com.google.protobuf</groupId>
        <artifactId>protobuf-java</artifactId>
        <version>3.19.4</version>
    </dependency>
</dependencies>

<build>
    <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:3.19.4:exe:${os.detected.classifier}</protocArtifact>
                <protocPlugins>
                    <protocPlugin>
                        <id>dubbo</id>
                        <groupId>org.apache.dubbo</groupId>
                        <artifactId>dubbo-compiler</artifactId>
                        <version>${dubbo.version}</version>
                        <mainClass>org.apache.dubbo.gen.tri.Dubbo3TripleGenerator</mainClass>
                    </protocPlugin>
                </protocPlugins>
            </configuration>
            <executions>
                <execution>
                    <goals>
                        <goal>compile</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

新增介面定義檔案 src/main/proto/hello.proto，Dubbo 使用 Protobuf 作為 IDL

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;

message HelloRequest {
    string name = 1;
}

message HelloReply {
    string message = 1;
}
service Greeter{
    rpc greet(HelloRequest) returns (HelloReply);
}

編譯 IDL

$ mvn clean install

編譯成功後，您可以在 target/generated-sources/protobuf/java 目錄中看到生成的程式碼檔案

$ ls org/apache/dubbo/hello/
DubboGreeterTriple.java HelloReply.java HelloRequest.java HelloWorldProto.java
Greeter.java HelloReplyOrBuilder.java HelloRequestOrBuilder.java

新增伺服器介面實作 src/main/java/org/apache/dubbo/GreeterImpl.java

package org.apache.dubbo;

import org.apache.dubbo.hello.DubboGreeterTriple;
import org.apache.dubbo.hello.HelloReply;
import org.apache.dubbo.hello.HelloRequest;

public class GreeterImpl extends DubboGreeterTriple. GreeterImplBase {
   @Override
   public HelloReply greet(HelloRequest request) {
      return HelloReply. newBuilder()
      .setMessage("Hello," + request.getName() + "!")
      .build();
   }
}

新增伺服器啟動類別 src/main/java/org/apache/dubbo/MyDubboServer.java

package org.apache.dubbo;

import org.apache.dubbo.common.constants.CommonConstants;
import org.apache.dubbo.config.ApplicationConfig;
import org.apache.dubbo.config.ProtocolConfig;
import org.apache.dubbo.config.RegistryConfig;
import org.apache.dubbo.config.ServiceConfig;
import org.apache.dubbo.config.bootstrap.DubboBootstrap;
import org.apache.dubbo.hello.Greeter;

import java.io.IOException;

public class MyDubboServer {

   public static void main(String[] args) throws IOException {
       ServiceConfig<Greeter> service = new ServiceConfig<>();
       service.setInterface(Greeter.class);
       service.setRef(new GreeterImpl());

       DubboBootstrap bootstrap = DubboBootstrap. getInstance();
       bootstrap. application(new ApplicationConfig("tri-stub-server"))
               .registry(new RegistryConfig("zookeeper://127.0.0.1:2181"))
               .protocol(new ProtocolConfig(CommonConstants.TRIPLE, 50051))
               .service(service)
               .start();
       System.out.println("Dubbo triple stub server started");
       System.in.read();
   }
}

新增客戶端啟動類別 src/main/java/org/apache/dubbo/MyDubboClient.java

package org.apache.dubbo;

import org.apache.dubbo.common.constants.CommonConstants;
import org.apache.dubbo.config.ApplicationConfig;
import org.apache.dubbo.config.ReferenceConfig;
import org.apache.dubbo.config.RegistryConfig;
import org.apache.dubbo.config.bootstrap.DubboBootstrap;
import org.apache.dubbo.hello.Greeter;
import org.apache.dubbo.hello.HelloReply;
import org.apache.dubbo.hello.HelloRequest;

public class MyDubboClient {
   public static void main(String[] args) {
      DubboBootstrap bootstrap = DubboBootstrap. getInstance();
      ReferenceConfig<Greeter> ref = new ReferenceConfig<>();
      ref. setInterface(Greeter. class);
      ref.setProtocol(CommonConstants.TRIPLE);
      ref.setProxy(CommonConstants.NATIVE_STUB);
      ref. setTimeout(3000);
      bootstrap. application(new ApplicationConfig("tri-stub-client"))
         .registry(new RegistryConfig("zookeeper://127.0.0.1:2181"))
         .reference(ref)
         .start();

      Greeter greeter = ref. get();
      HelloRequest request = HelloRequest.newBuilder().setName("Demo").build();
      HelloReply reply = greeter. greet(request);
      System.out.println("Received reply:" + reply);
    }
}

編譯程式碼
```
$ mvn clean install
```
啟動伺服器

$ mvn org.codehaus.mojo:exec-maven-plugin:3.0.0:java -Dexec.mainClass="org.apache.dubbo.MyDubboServer"
Dubbo triple stub server started

開啟新的終端機並啟動客戶端

$ mvn org.codehaus.mojo:exec-maven-plugin:3.0.0:java -Dexec.mainClass="org.apache.dubbo.MyDubboClient"
Received reply: message: "Hello, Demo!"

最後修改日期：2023 年 3 月 29 日：idl.md 中的拼寫錯誤 (#2465) (5db863851a0)

使用 IDL 定義跨語言服務

先決條件

建立專案

意見回饋