Serverless App Engine:Use Spring Boot to develop Dubbo applications

Step 1: Set up the project

Create a Maven project named spring-boot-dubbo-provider and add the following dependencies to pom.xml. This example uses Spring Boot 2.0.6.RELEASE.

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>2.0.6.RELEASE</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-actuator</artifactId>
    </dependency>
    <dependency>
        <groupId>org.apache.dubbo</groupId>
        <artifactId>dubbo-spring-boot-starter</artifactId>
        <version>2.7.3</version>
    </dependency>
    <dependency>
        <groupId>com.alibaba.nacos</groupId>
        <artifactId>nacos-client</artifactId>
        <version>1.1.1</version>
    </dependency>
</dependencies>

Step 2: Define the service interface

All Dubbo services are exposed through interfaces.

1. In src/main/java, create a package named com.alibaba.edas.boot.

2. In that package, create an interface named IHelloService:

package com.alibaba.edas.boot;

public interface IHelloService {
    String sayHello(String str);
}

Step 3: Implement the service

In the com.alibaba.edas.boot package, create a class named IHelloServiceImpl to implement IHelloService:

package com.alibaba.edas.boot;

import com.alibaba.dubbo.config.annotation.Service;

@Service
public class IHelloServiceImpl implements IHelloService {
    public String sayHello(String name) {
        return "Hello, " + name + " (from Dubbo with Spring Boot)";
    }
}

The @Service annotation here is com.alibaba.dubbo.config.annotation.Service provided by Dubbo — not the Spring @Service annotation.

Step 4: Configure the Dubbo service

In src/main/resources, create application.properties (or application.yaml) and add:

# Packages to scan for Dubbo annotations (@Service, @Reference)
dubbo.scan.basePackages=com.alibaba.edas.boot
dubbo.application.name=dubbo-provider-demo
dubbo.registry.address=nacos://127.0.0.1:8848

All three configuration items are required — none have default values.

dubbo.scan.basePackages: the package(s) containing @Service and @Reference annotations. Separate multiple packages with commas.

dubbo.registry.address: must start with nacos://, followed by the Nacos Server IP address and port. If you use the SAE-managed registry, SAE automatically replaces this address at runtime. If you use a self-managed Nacos instance, replace 127.0.0.1:8848 with its IP address and port.

Step 5: Start the provider

Create the Spring Boot main class DubboProvider and run it:

package com.alibaba.edas.boot;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DubboProvider {
    public static void main(String[] args) {
        SpringApplication.run(DubboProvider.class, args);
    }
}

Verify the provider

Log in to the Nacos console at http://127.0.0.1:8848. In the left-side navigation pane, click Services. Confirm that com.alibaba.edas.boot.IHelloService appears in the service list, along with its service group and provider IP address.

Step 1: Set up the project

Create a Maven project named spring-boot-dubbo-consumer and add the following dependencies to pom.xml. This example also uses Spring Boot 2.0.6.RELEASE.

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>2.0.6.RELEASE</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-actuator</artifactId>
    </dependency>
    <dependency>
        <groupId>org.apache.dubbo</groupId>
        <artifactId>dubbo-spring-boot-starter</artifactId>
        <version>2.7.3</version>
    </dependency>
    <dependency>
        <groupId>com.alibaba.nacos</groupId>
        <artifactId>nacos-client</artifactId>
        <version>1.1.1</version>
    </dependency>
</dependencies>

If you need to use Spring Boot 1.x, use Spring Boot 1.5.x with com.alibaba.boot:dubbo-spring-boot-starter:0.1.0. Note that the lifecycle of Spring Boot 1.x ended in August 2019 — using a newer version is strongly recommended.

Step 2: Reference the service interface

In src/main/java, create the package com.alibaba.edas.boot and add the same IHelloService interface as in the provider:

package com.alibaba.edas.boot;

public interface IHelloService {
    String sayHello(String str);
}

Step 3: Call the remote service

Create a controller that uses the @Reference annotation to inject the remote IHelloService and expose it via HTTP:

package com.alibaba.edas.boot;

import com.alibaba.dubbo.config.annotation.Reference;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class DemoConsumerController {

    @Reference
    private IHelloService demoService;

    @RequestMapping("/sayHello/{name}")
    public String sayHello(@PathVariable String name) {
        return demoService.sayHello(name);
    }
}

The @Reference annotation here is com.alibaba.dubbo.config.annotation.Reference provided by Dubbo.

Step 4: Configure the consumer

In src/main/resources, add the following to application.properties (or application.yaml):

dubbo.application.name=dubbo-consumer-demo
dubbo.registry.address=nacos://127.0.0.1:8848

Both configuration items are required. If Nacos Server runs on a different host, replace 127.0.0.1:8848 with the actual IP address and port.

Step 5: Start the consumer

Create the Spring Boot main class DubboConsumer and run it:

package com.alibaba.edas.boot;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DubboConsumer {
    public static void main(String[] args) {
        SpringApplication.run(DubboConsumer.class, args);
    }
}

Verify the consumer

Log in to the Nacos console at http://127.0.0.1:8848. In the left-side navigation pane, click Services. Confirm that com.alibaba.edas.boot.IHelloService appears in the service list, along with its service group and caller IP address.