介绍

Apache Dubbo™ (incubating) is a high-performance, java based, open source RPC framework open-sourced by Alibaba. As in many RPC systems, dubbo is based around the idea of defining a service, specifying the methods that can be called remotely with their parameters and return types. On the server side, the server implements this interface and runs a dubbo server to handle client calls. On the client side, the client has a stub that provides the same methods as the server.

Apache Dubbo (incubating) offers three key functionalities, which include interface based remote call, fault tolerance & load balancing, and automatic service registration & discovery. Apache Dubbo (incubating) framework is widely adopted inside Alibaba and outside by other companies including jingdong, dangdang, qunar, kaola, and many others.

环境构建

Prerequisites

• JDK: version 6 or higher

• Maven: version 3 or higher

Maven dependency

 
   
   
 

  
    
    
  
<dependency>
  
    
    
  
    <groupId>com.alibaba</groupId>
  
    
    
  
    <artifactId>dubbo</artifactId>
  
    
    
  
    <version>2.6.2</version>
  
    
    
  
</dependency>
 
   
   
 

Define service interface

Since both service provider and service consumer rely on the same interface, it is strongly recommended to put the interface definition below in one separated module which could be shared by both provider module and consumer module.

 
   
   
 

  
    
    
  
package com.alibaba.dubbo.demo;
  
    
    
  

  
    
    
  
public interface DemoService {
  
    
    
  
    String sayHello(String name);
  
    
    
  
}
 
   
   
 

Implement service provider

 
   
   
 

  
    
    
  
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;
  
    
    
  
    }
  
    
    
  
}
 
   
   
 

Configure service provider

The code snippet below shows how a dubbo service provider is configured with spring framework, which is recommended, however you could also use API configuration if it’s preferred.

 
   
   
 

  
    
    
  
<?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">
  
    
    
  
    <dubbo:application name="demo-provider"/>
  
    
    
  
    <dubbo:registry address="zookeeper://192.168.204.128:2181"/>
  
    
    
  
    <dubbo:protocol name="dubbo" port="20880"/>
  
    
    
  
    <dubbo:service interface="com.alibaba.dubbo.demo.DemoService" ref="demoService"/>
  
    
    
  
    <bean id="demoService" class="com.alibaba.dubbo.demo.provider.DemoServiceImpl"/>
  
    
    
  
</beans>
 
   
   
 

Start service provider

 
   
   
 

  
    
    
  
import org.springframework.context.support.ClassPathXmlApplicationContext;
  
    
    
  

  
    
    
  
public class Provider {
  
    
    
  
    public static void main(String[] args) throws Exception {
  
    
    
  
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(
  
    
    
  
                new String[] {"META-INF/spring/dubbo-demo-provider.xml"});
  
    
    
  
        context.start();
  
    
    
  
        // press any key to exit
  
    
    
  
        System.in.read();
  
    
    
  
    }
  
    
    
  
}
 
   
   
 

Configure service consumer

Again, the code below demonstrates spring integration

 
   
   
 

  
    
    
  
<?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">
  
    
    
  
    <dubbo:application name="demo-consumer"/>
  
    
    
  
    <dubbo:registry address="zookeeper://192.168.204.128:2181"/>
  
    
    
  
    <dubbo:reference id="demoService" interface="com.alibaba.dubbo.demo.DemoService"/>
  
    
    
  
</beans>
 
   
   
 

Run service consumer

 
   
   
 

  
    
    
  
import com.alibaba.dubbo.demo.DemoService;
  
    
    
  
import org.springframework.context.support.ClassPathXmlApplicationContext;
  
    
    
  

  
    
    
  
public class Consumer {
  
    
    
  
    public static void main(String[] args) throws Exception {
  
    
    
  
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(
  
    
    
  
                new String[]{"META-INF/spring/dubbo-demo-consumer.xml"});
  
    
    
  
        context.start();
  
    
    
  
        // obtain proxy object for remote invocation
  
    
    
  
        DemoService demoService = (DemoService) context.getBean("demoService");
  
    
    
  
        // execute remote invocation
  
    
    
  
        String hello = demoService.sayHello("world");
  
    
    
  
        // show the result
  
    
    
  
        System.out.println(hello);
  
    
    
  
    }
  
    
    
  
}
 
   
   
 

note befoer setting up the environment，you need to install zookeeper and make sure that the zookeeper is working properly.