Dubbo与Zookeeper、SpringMVC整合和使用
作为dubbo框架初学者，能让框架跑起来非常不容易，非常感谢网上诸多大神提供的文章，本人参考文章地址是：https://my.oschina.net/xshuai/blog/891281
不过别人的记录终究不适合自己，所以还是按照自己的风格简单记录下学习dubbo整合的步骤。
windows环境介绍：
myeclipse 10
jdk1.6
tomcat 6.0.35
一、安装Zookeeper
1.通过链接下载对应的包 http://www.apache.org/dist/zookeeper/
2.Zookeeper下载后解压即可，见下图
3.进入到conf里面，会看到zoo_sample.cfg文件。将zoo_sample.cfg改成bak文件，并复制一个修改为zoo.cfg，修改相关配置内容，注意修改的日志文件夹需要自己手动创建
4.进入D:\zookeeper-3.4.6\bin，双击zkServer.cmd，见到如下界面，就表示zookeeper已启动成功
二、安装dubbo
1.本人使用的是dubbo-admin-2.5.3.war，下载地址：http://pan.baidu.com/s/1eSnuqEQ
2.拷贝一个新的tomcat，并将tomcat/webapps里面的ROOT文件夹删掉
3.将dubbo-admin-2.5.3.war重命名为ROOT.war，并拷贝到tomcat/webapps目录下
4.启动tomcat
出现上述问题表示你没有启动zookeeper
5.dubbo发布成功后，输入http://localhost:8889/dubbo-admin-2.5.3/，此时出现登录页面，输入root/root进行登录，登录成功后如图
三、创建服务提供服务(provider)
项目结构如下图
相应的类中的代码如下：
web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <display-name></display-name> <listener-class> org.springframework.web.context.ContextLoaderListener </listener-class> <servlet> <servlet-name>provider</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value> classpath:applicationContext.xml,classpath:applicationContext-servlet.xml </param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>provider</servlet-name> <url-pattern>*.do</url-pattern> </servlet-mapping> <!-- 字符过滤器 --> <filter> <filter-name>Set Character Encoding</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>UTF-8</param-value> </init-param> </filter> <filter-mapping> <filter-name>Set Character Encoding</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
DemoService.java
package com.provider; public interface DemoService { String sayHello(String name); }
DemoServiceImpl.java
package com.provider; import org.springframework.stereotype.Service; @Service(value="demoService") public class DemoServiceImpl implements DemoService{ public String sayHello(String name) { return "Hello Dubbo,Hello " + name; } }
applicationContext.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:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation=" http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd" > <context:component-scan base-package="com.**"></context:component-scan> <!-- 引入服务提供者配置文件 --> <import resource="dubbo-provider.xml" /> </beans>
dubbo-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"> <!-- 提供方应用信息，用于计算依赖关系 --> <dubbo:application name="hello-world-provider" /> <!-- 使用multicast广播注册中心暴露服务地址 --> <!-- <dubbo:registry address="multicast://224.5.6.7:1234" /> --> <!-- 使用zookeeper注册中心暴露服务地址 --> <dubbo:registry address="zookeeper://127.0.0.1:2181" /> <!-- 用dubbo协议在20880端口暴露服务 --> <dubbo:protocol name="dubbo" port="20880" /> <!-- 声明需要暴露的服务接口 --> <dubbo:service interface="com.provider.DemoService" ref="demoService" /> <!-- 和本地bean一样实现服务 --> <!-- <bean id="demoService" class="com.provider.DemoServiceImpl" /> --> </beans>
applicationContext-servlet.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:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation=" http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd http://www.springframewor.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd" default-autowire="byName"> <!-- 默认的注解映射的支持 --> <mvc:annotation-driven> <mvc:message-converters register-defaults="true"> <bean class ="org.springframework.http.converter.StringHttpMessageConverter"> <property name ="supportedMediaTypes"> <list> <value>text/plain;charset=UTF-8</value> </list> </property> </bean> </mvc:message-converters> </mvc:annotation-driven> <!-- 视图解释类 --> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/jsp/" /> <property name="suffix" value=".jsp" /> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" /> </bean> <!-- 加载静态资源 --> <mvc:resources mapping="/css/**" location="/css/" /> <mvc:resources mapping="/js/**" location="/js/" /> <mvc:resources mapping="/images/**" location="/images/" /> </beans>
四、创建调用服务(customer)
customer服务架构和provider一致，拷贝一个即可
相应的代码如下：
applicationContext.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:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation=" http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd" > <context:component-scan base-package="com.**"></context:component-scan> <!-- 引入消费者配置文件 --> <import resource="dubbo-consumer.xml" /> </beans>
dubbo-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"> <!-- 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 --> <dubbo:application name="hello-world-customer"/> <!-- 使用multicast广播注册中心暴露发现服务地址 --> <!-- <dubbo:registry address="multicast://224.5.6.7:1234" /> --> <dubbo:registry address="zookeeper://127.0.0.1:2181" check="false"/> <!-- 生成远程服务代理，可以和本地bean一样使用demoService --> <dubbo:reference id="demoService" interface="com.provider.DemoService" check="false"/> </beans>
applicationContext-servlet.xml 和provider中的代码一致，就不贴出来了，本项目中其实这个文件可以不用
CustomerAction.java测试类
package com.customer; import javax.annotation.Resource; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.servlet.ModelAndView; import com.provider.DemoService; @Controller @RequestMapping(value="/customerTest") public class CustomerAction { @Resource(name="demoService") private DemoService demoService; @RequestMapping(value="/test.do") public ModelAndView test(HttpServletRequest request,HttpServletResponse response){ System.out.println("成功"); String result = demoService.sayHello("world"); System.out.println(result); return null; } }
五、共享服务
注意：需要将服务提供的接口打成jar包，放入customer中
六、测试
步骤：1、先启动zookeeper服务
2、启动dubbo服务
3、启动provider服务
4、启动customer服务
正常会出现如下界面
错误总结：
若按照上述测试步骤分别在不同的tomcat中启动服务，应该一切正常
若2、3、4这三步放在同一个tomcat中启动，会出现如下错误。
看下关键异常：No provider available for the service
此异常是由于服务没有可以使用的提供者，就是说在zookeeper注册中心（zookeeper-url）中没有可供消费者调用的url，消费者访问提供者就失败了。
具体原因分析：由于dobbo在启动的时候会去检查各服务之间的依赖关系，由于启动的时候消费者没有检查到提供者提供的服务（此时可能提供者还没启动），所以报错
在消费者配置文件中，需要将<dubbo:registry address="zookeeper://127.0.0.1:2181"/>修改为<dubbo:registry address="zookeeper://127.0.0.1:2181" check="false"/>
由于dubbo在注册的时候是默认会检查服务的依赖关系的
