Dubbo

 

Overview

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Serving 1,000+ services with 1,000,000,000+ invocations everyday, Dubbo becomes the key part of Alibaba's SOA solution and has been deployed to the whole alibaba.com family:

So, What is Dubbo?

Dubbo [] is a distributed service framework enpowers applications with service import/export capability with high performance RPC.

It's composed of three kernel parts:

• Remoting: a network communication framework provides sync-over-async and request-response messaging.
• Clustering: a remote procedure call abstraction with load-balancing/failover/clustering capabilities.
• Registry: a service directory framework for service registration and service event publish/subscription

Dubbo can:

• Integrate different types of RPC solutions(RMI/Hessian...) with unified behavior by the abstraction layer of RPC
• Support out-of-box, plug-able load balancing and fault tolerance strategies.
• Achieve graceful service upgrade/downgrade with service registry.

Quick Start

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Dubbo also support usage WITHOUT spring, please refer to: API Reference

Service Provider

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See: Demo Provider Installation

Define the service interface:

DemoService.java

package com.alibaba.dubbo.demo;

 

public interface DemoService {

 

    String sayHello(String name);

 

}

Provide the service implementation

DemoServiceImpl.java

package com.alibaba.dubbo.demo.provider;

 

import com.alibaba.dubbo.demo.DemoService;

 

public class DemoServiceImpl implements DemoService {

 

    public String sayHello(String name) {

        return "Hello " + name;

    }

 

}

Setup the spring configuration

provider.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"

    xsi:schemaLocation="http://www.springframework.org/schema/beans

        http://www.springframework.org/schema/beans/spring-beans.xsd

        http://code.alibabatech.com/schema/dubbo

        http://code.alibabatech.com/schema/dubbo/dubbo.xsd

        ">

 

    <!-- Application name -->

    <dubbo:application name="hello-world-app"  />

 

    <!-- registry address, used for service to register itself -->

    <dubbo:registry address="multicast://224.5.6.7:1234" />

 

    <!-- expose this service through dubbo protocol, through port 20880 -->

    <dubbo:protocol name="dubbo" port="20880" />

 

    <!-- which service interface do we expose? -->

    <dubbo:service interface="com.alibaba.dubbo.demo.DemoService" ref="demoService" />

 

    <!-- designate implementation -->

    <bean id="demoService" class="com.alibaba.dubbo.demo.provider.DemoServiceImpl" />

 

</beans>

Kick it off with following java code

Provider.java

import org.springframework.context.support.ClassPathXmlApplicationContext;

 

public class Provider {

 

    public static void main(String[] args) throws Exception {

        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[] {"provider.xml"});

        context.start();

 

        System.out.println("Press any key to exit.");

        System.in.read();

    }

 

}

Congrats! The DemoService now is exported by dubbo and waiting for incoming requests at port 20880.

Service Consumer

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See: Demo Consumer Installation

Setup the spring XML

consumer.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"

    xsi:schemaLocation="http://www.springframework.org/schema/beans

        http://www.springframework.org/schema/beans/spring-beans.xsd

        http://code.alibabatech.com/schema/dubbo

        http://code.alibabatech.com/schema/dubbo/dubbo.xsd

        ">

 

    <!-- consumer application name -->

    <dubbo:application name="consumer-of-helloworld-app"  />

 

    <!-- registry address, used for consumer to discover services -->

    <dubbo:registry address="multicast://224.5.6.7:1234" />

 

    <!-- which service to consume? -->

    <dubbo:reference id="demoService" interface="com.alibaba.dubbo.demo.DemoService" />

 

</beans>

Client side java code.

Consumer.java

import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.alibaba.dubbo.demo.DemoService;

 

public class Consumer {

 

    public static void main(String[] args) throws Exception {

        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[] {"consumer.xml"});

        context.start();

 

        DemoService demoService = (DemoService)context.getBean("demoService"); // get service invocation proxy

        String hello = demoService.sayHello("world"); // do invoke!

 

        System.out.println( hello ); // cool, how are you~

    }

 

}

For more, please click here for a complete user guide.