Spring Boot simplifies the configuration and deployment of microservice-oriented applications. Nacos provides the service registration and discovery as well as configuration management features. Using Spring Boot and Nacos together can help you improve development efficiency. This topic describes how to use Spring Boot annotations to develop a sample Dubbo microservice-oriented application based on Nacos.

Prerequisites

Before using Spring Boot to develop a Dubbo microservice-oriented application, complete the following tasks:
  • Download Maven and set the environment variables.
  • Download the latest version of Nacos Server.

  • Start Nacos Server.

    1. Decompress the downloaded Nacos Server package.
    2. Go to the nacos/bin directory and start Nacos Server as follows:
      • For Linux, UNIX, or MacOS: Run the sh startup.sh -m standalone command.
      • For Windows: Double-click the startup.cmd file to run the file.

Sample project

You can follow the steps described in this topic to build the project. Alternatively, you can directly download the sample project used in this topic, or clone the project by running the Git command git clone https://github.com/aliyun/alibabacloud-microservice-demo.git.

This project contains many demos. The demo used in this topic can be found in alibabacloud-microservice-demo/microservice-doc-demo/dubbo-samples-spring-boot.

Create a service provider

  1. Create a Maven project named spring-boot-dubbo-provider.
  2. Add required dependencies to the pom.xml file.

    The following takes Spring Boot 2.0.6.RELEASE as an example.

    <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>
  3. Develop a Dubbo service provider.
    All services in Dubbo are provided as interfaces.
    1. Create a package named com.alibaba.edas.boot in src/main/java.
    2. Create an interface named IHelloService that contains a SayHello method in com.alibaba.edas.boot. 
      package com.alibaba.edas.boot;
public interface IHelloService {
String sayHello(String str);
}
    3. Create a class named IHelloServiceImpl to implement the interface in com.alibaba.edas.boot. 
      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)";
 }
}
      Note In Dubbo, the service annotation is com.alibaba.dubbo.config.annotation.Service.
  4. Configure the Dubbo service.
    1. In src/main/resources, create a file named application.properties or application.yaml and open it.
    2. In application.properties or application.yaml, add the following configuration items. 
      # Base packages to scan Dubbo Components (e.g @Service , @Reference)
dubbo.scan.basePackages=com.alibaba.edas.boot
dubbo.application.name=dubbo-provider-demo
dubbo.registry.address=nacos://127.0.0.1:8848
      Note
      • You must specify values for the preceding three configuration items because they have no defaults.
      • The value of dubbo.scan.basePackages is the name of the package with code containing annotations com.alibaba.dubbo.config.annotation.Service and com.alibaba.dubbo.config.annotation.Reference. Separate multiple packages with commas (,).
      • The value of dubbo.registry.address must start with nacos://, followed by the IP address and port of Nacos Server. The IP address in the code example is a local address. If your Nacos Server is deployed on another machine, change it to the corresponding IP address.
  5. Develop and start the Spring Boot main class DubboProvider. 
        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);
        }

    }
  6. Log on to the Nacos console at http://127.0.0.1:8848. In the left-side navigation pane, click Services to view the list of providers.
    You can see that com.alibaba.edas.boot.IHelloService is available in the list of providers. In addition, you can query Service Group and Provider IP of the service.

Create a service consumer

  1. Create a Maven project named spring-boot-dubbo-consumer.
  2. Add required dependencies to the pom.xml file.
    The following takes Spring Boot 2.0.6.RELEASE as an example. 
        <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 want to use Spring Boot 1.x, select Spring Boot 1.5.x. The corresponding com.alibaba.boot:dubbo-spring-boot-starter version is 0.1.0.

    Note Spring Boot 1.x has reached the end of life in August 2019. We recommend that you use a later version to develop applications.
  3. Develop a Dubbo consumer.
    1. Create a package named com.alibaba.edas.boot in src/main/java.
    2. Create an interface named IHelloService that contains a SayHello method in com.alibaba.edas.boot. 
      package com.alibaba.edas.boot;

public interface IHelloService {
 String sayHello(String str);
}
  4. Develop a Dubbo service call.

    For example, you need to call a remote Dubbo service once in a controller. The code is as follows. 

    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);
        }
    }
    Note The Reference annotation is com.alibaba.dubbo.config.annotation.Reference.
  5. Add the following configuration items to the application.properties or application.yaml file. 
    dubbo.application.name=dubbo-consumer-demo
dubbo.registry.address=nacos://127.0.0.1:8848
    Note
    • You must specify values for the preceding two configuration items because they have no defaults.
    • The value of dubbo.registry.address must start with nacos://, followed by the IP address and port of Nacos Server. The IP address in the code example is a local address. If your Nacos Server is deployed on another machine, change it to the corresponding IP address.
  6. Develop and start the Spring Boot main class DubboConsumer. 
    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);
    }

}
  7. Log on to the Nacos console at http://127.0.0.1:8848. In the left-side navigation pane, click Services. On the Services page, click the Callers tab to view the list of callers.
    You can see that com.alibaba.edas.boot.IHelloService is available in the list. In addition, you can view the group and caller IP address of the service.

Verify the result

`curl http://localhost:8080/sayHello/EDAS`

`Hello, EDAS (from Dubbo with Spring Boot)`

Deploy the application to EDAS

You can deploy the application that uses local Nacos as the registry directly to Enterprise Distributed Application Service (EDAS) without making any changes. This registry will be automatically replaced with the registry in EDAS.

Based on your actual needs, you can choose to deploy the application in an Elastic Compute Service (ECS) cluster or Container Service Kubernetes cluster by using the console or command line tools. For more information, see the following documentation.

If you use the console for deployment, follow these steps in your local application before deploying it:

  1. Add the following configuration of the packaging plug-in to the pom.xml file.
    • Provider 
      <build>
 <plugins>
       <plugin>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-maven-plugin</artifactId>
           <executions>
               <execution>
                   <goals>
                       <goal>repackage</goal>
                   </goals>
                   <configuration>
                       <classifier>spring-boot</classifier>
                       <mainClass>com.alibaba.edas.boot.DubboProvider</mainClass>
                   </configuration>
               </execution>
           </executions>
       </plugin>
 </plugins>
</build>
    • Consumer 
      <build>
 <plugins>
       <plugin>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-maven-plugin</artifactId>
           <executions>
               <execution>
                   <goals>
                       <goal>repackage</goal>
                   </goals>
                   <configuration>
                       <classifier>spring-boot</classifier>
                       <mainClass>com.alibaba.edas.boot.DubboConsumer</mainClass>
                   </configuration>
               </execution>
           </executions>
       </plugin>
 </plugins>
</build>
  2. Run mvn clean package to package your local program into a JAR file.

References

  • In addition to Spring Boot, you can also develop Dubbo microservice-oriented applications by using XML. For more information, see Host Dubbo applications to EDAS.
  • If you are using edas-dubbo-extension, see Host Dubbo applications to EDAS with edas-dubbo-extension. If you use edas-dubbo-extension to host Dubbo applications, you cannot use related capabilities provided by EDAS, such as Dubbo service governance. Therefore, we recommend that you migrate to Nacos instead.