一、前言
Dubbo 作为SOA服务化治理方案的核心框架,用于提高业务逻辑的复用、整合、集中管理,具有极高的可靠性(HA)和伸缩性,被应用于阿里巴巴各成员站点,同时在包括JD、当当在内的众多互联网项目中有着广泛应用。dubbo 通过高性能 RPC 实现服务的输出和输入功能,框架基于 Spring Framework 进行无缝集成,使用过程中基本看不到 Dubbo API的直接调用,Dubbo服务支持RMI、Hessian、Dubbo、WebService等众多通信协议,同时提供了对服务的监控和管理平台,属于一套完整的SOA解决方案。
详细介绍请参照官方地址: http://alibaba.github.io/dubbo-doc-static/Home-zh.htm ,不再重复描述,本文主要记录了详细的开发整合步骤。 引用一张官方提供的dubbo架构图:
Provider 暴露服务方称之为“服务提供者”。
Consumer 调用远程服务方称之为“服务消费者”。
Registry 服务注册与发现的中心目录服务称之为“服务注册中心”。
Monitor 统计服务的调用次调和调用时间的日志服务称之为“服务监控中心”。
- Container 服务运行“容器”。
二、源码构建
1、dubbo基于maven构建,需要先配置maven环境,当然如果你不想构建源码,也可以直接下载对应版本的发行包。
2、dubbo构建需要依赖opensesame组件,先通过 git 获取并安装opensesame,源码地址:
https://github.com/alibaba/opensesame
执行maven安装:mvn install
3、通过下面 git 地址获取对应版本的 dubbo 源码,官方推荐使用 dubbo 2.4.9,本文基于trunk版本构建。
https://github.com/alibaba/dubbo
maven构建:mvn clean install -Dmaven.test.skip,在漫长的等待后(过程需要通过网络下载依赖资源)会有如下提示,生成的 jar 包位于各自目录的target文件夹。
[INFO] ------------------------------------------------------------------------ [INFO] Reactor Summary: [INFO] [INFO] dubbo-parent ....................................... SUCCESS [ 1.272 s] [INFO] dubbo-common ....................................... SUCCESS [ 4.572 s] [INFO] dubbo-container .................................... SUCCESS [ 0.024 s] [INFO] dubbo-container-api ................................ SUCCESS [ 1.148 s] [INFO] dubbo-container-spring ............................. SUCCESS [ 0.524 s] [INFO] dubbo-container-jetty .............................. SUCCESS [ 0.420 s] [INFO] dubbo-container-log4j .............................. SUCCESS [ 0.448 s] [INFO] dubbo-container-logback ............................ SUCCESS [ 0.468 s] [INFO] dubbo-remoting ..................................... SUCCESS [ 0.016 s] [INFO] dubbo-remoting-api ................................. SUCCESS [ 1.864 s] [INFO] dubbo-remoting-netty ............................... SUCCESS [ 1.125 s] [INFO] dubbo-remoting-mina ................................ SUCCESS [ 0.696 s] [INFO] dubbo-remoting-grizzly ............................. SUCCESS [ 0.680 s] [INFO] dubbo-remoting-p2p ................................. SUCCESS [ 1.048 s] [INFO] dubbo-remoting-http ................................ SUCCESS [ 0.616 s] [INFO] dubbo-remoting-zookeeper ........................... SUCCESS [ 0.716 s] [INFO] dubbo-rpc .......................................... SUCCESS [ 0.016 s] [INFO] dubbo-rpc-api ...................................... SUCCESS [ 1.608 s] [INFO] dubbo-rpc-default .................................. SUCCESS [ 1.396 s] [INFO] dubbo-rpc-injvm .................................... SUCCESS [ 0.760 s] [INFO] dubbo-rpc-rmi ...................................... SUCCESS [ 0.416 s] [INFO] dubbo-rpc-hessian .................................. SUCCESS [ 0.584 s] [INFO] dubbo-rpc-http ..................................... SUCCESS [ 0.580 s] [INFO] dubbo-rpc-webservice ............................... SUCCESS [ 0.536 s] [INFO] dubbo-cluster ...................................... SUCCESS [ 2.208 s] [INFO] dubbo-registry ..................................... SUCCESS [ 0.020 s] [INFO] dubbo-registry-api ................................. SUCCESS [ 1.241 s] [INFO] dubbo-monitor ...................................... SUCCESS [ 0.016 s] [INFO] dubbo-monitor-api .................................. SUCCESS [ 0.464 s] [INFO] dubbo-filter ....................................... SUCCESS [ 0.016 s] [INFO] dubbo-filter-validation ............................ SUCCESS [ 0.608 s] [INFO] dubbo-filter-cache ................................. SUCCESS [ 0.604 s] [INFO] dubbo-registry-default ............................. SUCCESS [ 0.540 s] [INFO] dubbo-monitor-default .............................. SUCCESS [ 0.588 s] [INFO] dubbo-registry-multicast ........................... SUCCESS [ 0.632 s] [INFO] dubbo-config ....................................... SUCCESS [ 0.016 s] [INFO] dubbo-config-api ................................... SUCCESS [ 1.500 s] [INFO] dubbo-config-spring ................................ SUCCESS [ 1.520 s] [INFO] dubbo-rpc-thrift ................................... SUCCESS [ 1.032 s] [INFO] dubbo-rpc-memcached ................................ SUCCESS [ 0.464 s] [INFO] dubbo-rpc-redis .................................... SUCCESS [ 0.500 s] [INFO] dubbo-registry-zookeeper ........................... SUCCESS [ 0.656 s] [INFO] dubbo-registry-redis ............................... SUCCESS [ 0.640 s] [INFO] dubbo .............................................. SUCCESS [ 1.009 s] [INFO] dubbo-simple ....................................... SUCCESS [ 0.016 s] [INFO] dubbo-registry-simple .............................. SUCCESS [01:43 min] [INFO] dubbo-monitor-simple ............................... SUCCESS [ 10.379 s] [INFO] dubbo-admin ........................................ SUCCESS [04:03 min] [INFO] dubbo-demo ......................................... SUCCESS [ 0.016 s] [INFO] dubbo-demo-api ..................................... SUCCESS [ 0.308 s] [INFO] dubbo-demo-provider ................................ SUCCESS [ 2.700 s] [INFO] dubbo-demo-consumer ................................ SUCCESS [ 2.745 s] [INFO] dubbo-test ......................................... SUCCESS [ 0.012 s] [INFO] dubbo-test-benchmark ............................... SUCCESS [01:01 min] [INFO] dubbo-test-compatibility ........................... SUCCESS [ 0.188 s] [INFO] dubbo-test-integration ............................. SUCCESS [ 0.052 s] [INFO] dubbo-test-examples ................................ SUCCESS [ 1.640 s] [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 07:42 min [INFO] Finished at: 2015-01-20T14:36:43+08:00 [INFO] Final Memory: 282M/895M [INFO] ------------------------------------------------------------------------
4、 构建过程中如果出现maven网络连接相关的异常信息,可以尝试将以下maven mirror 地址添加到 settings.xml 文件。
<mirror> <id>CN</id> <mirrorOf>central</mirrorOf> <name>OSChina Central</name> <url>http://maven.oschina.net/content/groups/public/</url> </mirror> <mirror> <id>kafeitu</id> <mirrorOf>central</mirrorOf> <name>Human Readable Name for this Mirror.</name> <url>http://maven.kafeitu.me/nexus/content/repositories/public</url> </mirror> <mirror> <id>lvu.cn</id> <name>lvu.cn</name> <url>http://lvu.cn/nexus/content/groups/public</url> <mirrorOf>*</mirrorOf> </mirror>
三、Zookeeper部署(Registry 服务注册中心)
D ubbo 缺省配置通过 multicast 注册中心广播实现 Provider 和 Consumer 之间的简单远程过程调用(Simple RPC),不需要通过 Registry 注册中心进行注册调度 ,类似于spring rmi remoting调用,但由于不是Cluster部署,所以作为分布 式RPC框架官方建议使用 Zookeeper 作为Registry注册中心服务器(同样支持Redis)实现服务的注册、发现、路由功能。Dubbo在Zookeeper服务器端只增加了dubbo数据节点(如下图),无需其他任何配置,所以只需安装或使用现有 Zookeeper 服务器即可,关于Zookeeper的安装部署可以参照之前的博文: http://www.cnblogs.com/lengfo/p/4146797.html ,不再重复介绍。
Zookeeper同样支持集群部署,提供最终一致性数据服务,本文实验环境只使用了一台Linux服务器作为ZK Registry注册服务器,zoo.cfg配置文件如下。
# The number of milliseconds of each tick tickTime=2000 # The number of ticks that the initial # synchronization phase can take initLimit=10 # The number of ticks that can pass between # sending a request and getting an acknowledgement syncLimit=5 # the directory where the snapshot is stored. # do not use /tmp for storage, /tmp here is just # example sakes. dataDir=/home/glf/zookeeperServer/data dataLogDir=/home/glf/zookeeperServer/logs # the port at which the clients will connect clientPort=2181 # the maximum number of client connections. # increase this if you need to handle more clients #maxClientCnxns=60 # # Be sure to read the maintenance section of the # administrator guide before turning on autopurge. # # http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance # # The number of snapshots to retain in dataDir #autopurge.snapRetainCount=3 # Purge task interval in hours # Set to "0" to disable auto purge feature #autopurge.purgeInterval=1
四、服务提供方开发(Provider)
1、创建Java测试项目 DubboDemo ,集成Spring Framework。由于dubbo基于Spring的Schema扩展进行加载,依赖于低版本spring,所以如果开发项目中使用高版本(spring 3.0及以上)会出现xml解析冲突,官方QA中也有相关提及: http://alibaba.github.io/dubbo-doc-static/FAQ-zh.htm ,所以本文只集成了2.5.6版本spring,更多相关版本问题也有待进一步研究,Todo。
2、集成dubbo及相关依赖包,参照下图,如果使用dubbo其他特性可能需要依赖更多包,比如jedis。
3、创建测试服务接口(IGoodsManager)
package ibusiness; public interface IGoodsManager { public String LoadGoods(); }
4、创建测试服务实现类(GoodsManager)
package business; import com.alibaba.dubbo.rpc.RpcContext; import ibusiness.IGoodsManager; public class GoodsManager implements IGoodsManager { @Override public String LoadGoods() { return "可口可乐,雀巢咖啡 " + "/n response form provider: " + RpcContext.getContext().getLocalAddress(); } }
5、通过spring 集成并配置dubbo测试服务,同时指定registry的zookeeper服务器地址。
<?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 服务提供者应用名称 --> <dubbo:application name="demo-dubbo-provider-app" /> <!--dubbo 注册中心--> <dubbo:registry address="zookeeper://10.129.221.64:2181" /> <!--服务提供者 端口--> <dubbo:protocol name="dubbo" port="30001" /> <!--dubbo提供服务--> <dubbo:service interface="ibusiness.IGoodsManager" ref="goodsService" /> <!--spring bean 对象--> <bean id="goodsService" class="business.GoodsManager" /> </beans>
6、编写控制台程序启动spring容器,编译并打包Provider.jar
package dubboProvider; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class DubboProvider { public static void main(String[] args) { try { // 初始化Spring ApplicationContext ctx = new ClassPathXmlApplicationContext("dubboProvider\\dubboProvider.xml"); System.out.println("dubbo provider is running..."); System.in.read(); } catch (Exception ex) { ex.printStackTrace(); } } }
五、服务消费方开发(Consumer)
1、通过spring 配置指定registry的zookeeper地址,实现对dubbo远程服务的调用
<?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-dubbo-consumer-app" /> <dubbo:registry address="zookeeper://10.129.221.64:2181" /> <!-- 和本地bean一样实现服务 --> <dubbo:reference id="goodsService" interface="ibusiness.IGoodsManager" /> </beans>
2、编写调用测试客户端代码,从容器中获取远程bean并调用。
package dubboConsumer; import ibusiness.IGoodsManager; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class DubboConsumer { public static void main(String[] args) { // 初始化Spring ApplicationContext ctx = new ClassPathXmlApplicationContext("dubboConsumer\\dubboConsumer.xml"); IGoodsManager goodsManager = (IGoodsManager) ctx.getBean("goodsService"); // 获取远程服务代理 String goodsStr = goodsManager.LoadGoods() ; // 执行远程方法 System.out.println(goodsStr); } }
3、 分别启动 provider、consumer 的测试程序发布和调用服务,即简单实现了基于 zookeeper registry 的 dubbo 远程过程调用。
六、More about dubbo
以上简单的展示dubbo的RPC服务能力,更多关于dubbo的集群管理、监控、负载均衡、高可用性、可扩展、伸缩性等相关内容请期待后续博文。