A distributed service framework--Dubbo instance

Dubbo is a distributed service framework. Since it is a service, there must be service providers and service callers.

Next, we first write a service provider. The project still uses the project in the previous article Getting Started with Spring 4.

##We add dubbo’s dependency in pom.xml

com. alibaba
dubbo
2.5.3

Write the following class:

package com.mm.service;public interface WeatherService {public String getMessage(String city);
}

package com.mm.service.impl;import com.mm.service.WeatherService;public class WeatherServiceImpl implements WeatherService{

    @Overridepublic String getMessage(String city) {return city+"天气晴朗，局部有阵雨";
    }

}

Create a spring configuration file (provider.xml)

<?xml  version="1.0" encoding="UTF-8"?>
<beans>
 
    <!-- 提供方应用信息，用于计算依赖关系 -->
    <application></application>
 
    <!-- 使用multicast广播注册中心暴露服务地址 -->
    <registry></registry>
 
    <!-- 用dubbo协议在20880端口暴露服务 -->
    <protocol></protocol>
 
    <!-- 声明需要暴露的服务接口 -->
    <service></service>
 
    <!-- 和本地bean一样实现服务 -->
    <bean></bean>
 
</beans>

Create a new console program for service startup

package com.mm.main.dubbo;import java.io.IOException;import org.springframework.context.support.ClassPathXmlApplicationContext;public class DubboProvider {public static void main(String[] args) throws IOException{
         ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[] {"config/provider.xml"});
         context.start();
         System.in.read(); // 按任意键退出    }
}

Then, we started the service provider and found no error message. The service should have started successfully.

Next, we write the service caller, officially called the consumer. For convenience here, I directly copied a copy of the code to the new workspace and simply configured maven and tomcat. And delete the corresponding implementation class. The code structure is as follows:

consumer.xml file is as follows:

<?xml  version="1.0" encoding="UTF-8"?>
<beans>
 
    <!-- 消费方应用名，用于计算依赖关系，不是匹配条件，不要与提供方一样 -->
    <application></application>
 
    <!-- 使用multicast广播注册中心暴露发现服务地址 -->
    <registry></registry>
 
    <!-- 生成远程服务代理，可以和本地bean一样使用demoService -->
    <reference></reference>
 
</beans>

Create a new console program, The call for the service

package com.mm.main.dubbo;import java.io.IOException;import org.springframework.context.support.ClassPathXmlApplicationContext;import com.mm.service.WeatherService;public class DubboConsumer {public static void main(String[] args) throws IOException{
         ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[] {"config/consumer.xml"});
         WeatherService  demoService = (WeatherService )context.getBean("weatherService"); // 获取远程服务代理 String hello = demoService.getMessage("北京"); // 执行远程方法 System.out.println( hello ); // 显示调用结果    }
}

The console output is as follows:

At the same time we are in the provider's The console will also find the following information:

Additional supplement:

Used in the spring configuration file When using dubbo tags, an error will be reported. It shouldn't actually affect it, it's probably an issue with eclipse file verification. But I felt a little unhappy, so...

First, find dubbo-2.5.3.jar in the local maven warehouse, decompress it and find the xsd file, as follows:

Open the eclipse configuration

will The value of key is changed to:

Then, right-click provider.xml and validate. After a long wait, the error message disappears.

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