# git clone https://github.com/apache/dubbo-samples.git
# cd dubbo-samples/java/dubbo-samples-api

<properties>
    <dubbo.version>2.7.8</dubbo.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.apache.dubbo</groupId>
        <artifactId>dubbo</artifactId>
        <version>${dubbo.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.dubbo</groupId>
        <artifactId>dubbo-dependencies-zookeeper</artifactId>
        <version>${dubbo.version}</version>
        <type>pom</type>
    </dependency>
</dependencies>

package org.apache.dubbo.samples.api;

public interface GreetingsService {
    String sayHi(String name);
}

package org.apache.dubbo.samples.provider;

import org.apache.dubbo.samples.api.GreetingsService;

public class GreetingsServiceImpl implements GreetingsService {
    @Override
    public String sayHi(String name) {
        return "hi, " + name;
    }
}

package org.apache.dubbo.samples.provider;


import org.apache.dubbo.config.ApplicationConfig;
import org.apache.dubbo.config.RegistryConfig;
import org.apache.dubbo.config.ServiceConfig;
import org.apache.dubbo.samples.api.GreetingsService;

import java.util.concurrent.CountDownLatch;

public class Application {
    private static String zookeeperHost = System.getProperty("zookeeper.address", "127.0.0.1");

    public static void main(String[] args) throws Exception {
        ServiceConfig<GreetingsService> service = new ServiceConfig<>();
        service.setApplication(new ApplicationConfig("first-dubbo-provider"));
        service.setRegistry(new RegistryConfig("zookeeper://" + zookeeperHost + ":2181"));
        service.setInterface(GreetingsService.class);
        service.setRef(new GreetingsServiceImpl());
        service.export();

        System.out.println("dubbo service started");
        new CountDownLatch(1).await();
    }
}

# mvn clean package
# mvn -Djava.net.preferIPv4Stack=true -Dexec.mainClass=org.apache.dubbo.samples.provider.Application exec:java

package org.apache.dubbo.samples.client;


import org.apache.dubbo.config.ApplicationConfig;
import org.apache.dubbo.config.ReferenceConfig;
import org.apache.dubbo.config.RegistryConfig;
import org.apache.dubbo.samples.api.GreetingsService;

public class Application {
    private static String zookeeperHost = System.getProperty("zookeeper.address", "127.0.0.1");

    public static void main(String[] args) {
        ReferenceConfig<GreetingsService> reference = new ReferenceConfig<>();
        reference.setApplication(new ApplicationConfig("first-dubbo-consumer"));
        reference.setRegistry(new RegistryConfig("zookeeper://" + zookeeperHost + ":2181"));
        reference.setInterface(GreetingsService.class);
        GreetingsService service = reference.get();
        String message = service.sayHi("dubbo");
        System.out.println(message);
    }
}

# mvn clean package
# mvn -Djava.net.preferIPv4Stack=true -Dexec.mainClass=org.apache.dubbo.samples.client.Application exec:java

  mvn clean install