dubbo的demo中的provider實現很簡單,
1.接口如下:
package com.alibaba.dubbo.demo;
public interface DemoService {
String sayHello(String name);
}
2.實現類:
package com.alibaba.dubbo.demo.provider;
import com.alibaba.dubbo.demo.DemoService;
import com.alibaba.dubbo.rpc.RpcContext;
import java.text.SimpleDateFormat;
import java.util.Date;
public class DemoServiceImpl implements DemoService {
public String sayHello(String name) {
System.out.println("[" + new SimpleDateFormat("HH:mm:ss").format(new Date()) + "] Hello " + name + ", request from consumer: " + RpcContext.getContext().getRemoteAddress());
return "Hello " + name + ", response form provider: " + RpcContext.getContext().getLocalAddress();
}
}
3.主要配置文件dubbo-demo-provider.xml內容如下:
<dubbo:application name="demo-provider"/>
<!-- use multicast registry center to export service -->
<dubbo:registry address="multicast://224.5.6.7:1234"/>
<!-- use dubbo protocol to export service on port 20880 -->
<dubbo:protocol name="dubbo" port="20880"/>
<!-- service implementation, as same as regular local bean -->
<bean id="demoService" class="com.alibaba.dubbo.demo.provider.DemoServiceImpl"/>
<!-- declare the service interface to be exported -->
<dubbo:service interface="com.alibaba.dubbo.demo.DemoService" ref="demoService"/>
4.main類:
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Provider {
public static void main(String[] args) throws Exception {
//Prevent to get IPV6 address,this way only work in debug mode
//But you can pass use -Djava.net.preferIPv4Stack=true,then it work well whether in debug mode or not
System.setProperty("java.net.preferIPv4Stack", "true");
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[]{"META-INF/spring/dubbo-demo-provider.xml"});
context.start();
System.in.read(); // press any key to exit
}
}
5.那麼dubbo配置文件的解析是怎麼解決的呢?是什麼時候開始的呢?
1)在源碼的dubbo-config下的dubo-config-spring中的META-INF下面有兩個文件:
spring.schemas和spring.handlers
spring.schemas內容爲:http\://code.alibabatech.com/schema/dubbo/dubbo.xsd=META-INF/dubbo.xsd
解說:dubbo.xsd是dubbo在spring中可以使用的元素的定義,如protocol,registry等
spring.handlers內容爲:
http\://code.alibabatech.com/schema/dubbo=com.alibaba.dubbo.config.spring.schema.DubboNamespaceHandler
解說:DubboNamespaceHandler是註冊dubbo中用到的各個元素的解析類,它的源碼內容如下:
public class DubboNamespaceHandler extends NamespaceHandlerSupport {
static {
Version.checkDuplicate(DubboNamespaceHandler.class);
}
public void init() {
registerBeanDefinitionParser("application", new DubboBeanDefinitionParser(ApplicationConfig.class, true));
registerBeanDefinitionParser("module", new DubboBeanDefinitionParser(ModuleConfig.class, true));
registerBeanDefinitionParser("registry", new DubboBeanDefinitionParser(RegistryConfig.class, true));
registerBeanDefinitionParser("monitor", new DubboBeanDefinitionParser(MonitorConfig.class, true));
registerBeanDefinitionParser("provider", new DubboBeanDefinitionParser(ProviderConfig.class, true));
registerBeanDefinitionParser("consumer", new DubboBeanDefinitionParser(ConsumerConfig.class, true));
registerBeanDefinitionParser("protocol", new DubboBeanDefinitionParser(ProtocolConfig.class, true));
registerBeanDefinitionParser("service", new DubboBeanDefinitionParser(ServiceBean.class, true));
registerBeanDefinitionParser("reference", new DubboBeanDefinitionParser(ReferenceBean.class, false));
registerBeanDefinitionParser("annotation", new DubboBeanDefinitionParser(AnnotationBean.class, true));
}
而DubboBeanDefinitionParser是具體解析的類,解析dubbo-demo-provider.xml中的配置,並封裝相關的bean.
從而進行服務啓動的一些準備,包括服務export,註冊等。
2)什麼開始的,通過下面的截圖可以一目瞭然:
注:1)dubbo的源碼地址:https://github.com/alibaba/dubbo
2)spring schema的學習請看以下鏈接:https://segmentfault.com/a/1190000007047168