一、背景
随着互联网的发展，网站应用的规模不断扩大，常规的垂直应用架构已无法应对，分布式服务架构以及流动计算架构势在必行。
当越来越的的接口与实现类的增加后，duboo的xml配置会越来越多，为了防止几百几千行的代码，减少开发人员配置xml的工作量，使用duboo的注解模式，减少配置多出问题多的可能性！
二、Dubbo使用案例
Duboo注解
接口类项目：DubboServiceInterface 
仅仅是一个接口类项目！接口是普通接口！ 
注意：将接口类项目打包成jar分别放入服务端项目跟客户端项目！
服务端项目：DubboServiceProvider 
实现类fooserviceImpl.java 
package com.alibaba.dubbo.demo.imp;
import com.alibaba.dubbo.config.annotation.Service;
import com.alibaba.dubbo.demo.DemoService;
@Service(version="1.0")
public class FooServiceImpl implements DemoService {
@Override
public String sayHello(String name) {
return "Hello " + name;
}
}
web.xml 配置扫描内容 
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>DubboServiceProvider</display-name>
<servlet>
<servlet-name>spring</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<url-pattern>*</url-pattern>
</servlet-mapping>
<listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<context-param>
<param-name>contextConfigLocation</param-name> <param-value>classpath*:applicationContext.xml</param-value>
</context-param>
</web-app>
applicationContext.xml 配置 
<?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">
<!-- 服务端- 服务提供方 -->
<!-- 公共信息，也可以用dubbo.properties配置 -->
<dubbo:application name="test" />
<!-- 链接zookeeper -->
<dubbo:registry address="zookeeper://127.0.0.1:2181/" group="test"/>
<dubbo:consumer timeout="5000"/>
<!-- 扫描注解包路径，多个包用逗号分隔，不填pacakge表示扫描当前ApplicationContext中所有的类 -->
<dubbo:annotation package="com.unj.dubbotest.serviceImp" />
<!-- xml配置 ： 声明需要暴露的服务接口 -->
<!-- <dubbo:service interface="com.alibaba.dubbo.demo.DemoService" ref="demoService" /> -->
<!-- xml配置 ：和本地bean一样实现服务-->
<!-- <bean id="demoService" class="com.unj.dubbotest.serviceImp.FooServiceImpl" /> -->
</beans>
测试类Provider 
package com.alibaba.dubbo.test;
import java.io.IOException;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Provider {
@Before
public void setUp() throws Exception {
}
@Test
public void testMain() throws IOException {
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(
new String[] { "applicationContext.xml" });
context.start();
System.in.read();// 按任意键退出
}
}
lib下的jar包 
客户端项目：DubboServiceConsumer 
web.xml 配置扫描内容 
applicationContext.xml文件 
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
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">
<!-- 客户端- 服务消费方 -->
<!-- 公共信息，也可以用dubbo.properties配置 -->
<dubbo:application name="xx" />
<dubbo:registry address="zookeeper://127.0.0.1:2181" />
<dubbo:consumer timeout="5000"/>
<!-- 扫描注解包路径，多个包用逗号分隔，不填pacakge表示扫描当前ApplicationContext中所有的类 -->
<dubbo:annotation package="com.unj.dubbotest.action" />
</beans>
测试类:Consumer 
package com.unj.dubbotest.action;
import java.io.IOException;
import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.alibaba.dubbo.config.annotation.Reference;
import com.alibaba.dubbo.demo.DemoService;
public class Consumer{
@Reference(version = "1.0")
private DemoService demoService;
@Test
public void mainTest() throws IOException {
ClassPathXmlApplicationContext context =new ClassPathXmlApplicationContext(
new String[] {"applicationContext.xml"});
context.start();
demoService = (DemoService)context.getBean("demoService"); // 获取远程服务代理
String hello = demoService.sayHello("world"); // 执行远程方法
System.out.println( hello ); // 显示调用结果
}
}
lib下的jar包 
获取海量视频 