通俗易懂的Dubbo学习（一） dubbo服务者和消费者的简单案例
随着互联网的不断发展，系统应用的规模也在不断扩大，常规的垂直类型应用架构已经无法较好的应对，所以分布式服务架构以及流动计算机架构的趋势越来越明显。在这种大规模类型的服务化架构到来之前，可能只是通过rmi,hessian等工具来进行简单的服务引用的处理，但是当规模量逐渐提升之后，过多的服务也带来了一定的繁琐问题，例如说对于服务url的管理。
当不同服务的调用量逐渐提升之后，服务的容量问题也越来越不明确。
对于错综复杂的服务调度关系，越来越繁琐，不利于统筹管理。
基于上述的一些情况，dubbo服务架构开始横空出世，其基本架构如下所示：
说了这么多的背景介绍，我们还是直接用个案例来进行介绍会比较好：
首先需要在ide里面搭建好相应的maven结构：
然后导入相应的pom依赖：
dubbo-root：
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0modelVersion>
<groupId>com.sisegroupId>
<artifactId>dubbo-rootartifactId>
<packaging>pompackaging>
<version>1.0-SNAPSHOTversion>
<modules>
<module>dubbo-providemodule>
<module>dubbo-apimodule>
<module>dubbo-consumermodule>
modules>
<properties>
<motan.version>0.3.0motan.version>
<dubbo.version>2.5.3dubbo.version>
<dubbox.version>2.8.4dubbox.version>
<spring.version>4.3.6.RELEASEspring.version>
<java.version>1.7java.version>
<project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
properties>
<dependencies>
<dependency>
<groupId>com.alibabagroupId>
<artifactId>dubboartifactId>
<version>2.5.3version>
<exclusions>
<exclusion>
<groupId>org.springframeworkgroupId>
<artifactId>springartifactId>
exclusion>
exclusions>
dependency>
<dependency>
<groupId>com.github.sgroschupfgroupId>
<artifactId>zkclientartifactId>
<version>0.1version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-coreartifactId>
<version>${spring.version}version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-beansartifactId>
<version>${spring.version}version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-contextartifactId>
<version>${spring.version}version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-jdbcartifactId>
<version>${spring.version}version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-webartifactId>
<version>${spring.version}version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-webmvcartifactId>
<version>${spring.version}version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-aopartifactId>
<version>${spring.version}version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-txartifactId>
<version>${spring.version}version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-ormartifactId>
<version>${spring.version}version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-context-supportartifactId>
<version>${spring.version}version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-testartifactId>
<version>${spring.version}version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-jmsartifactId>
<version>${spring.version}version>
dependency>
<dependency>
<groupId>org.aspectjgroupId>
<artifactId>aspectjrtartifactId>
<version>1.6.11version>
dependency>
<dependency>
<groupId>org.aspectjgroupId>
<artifactId>aspectjweaverartifactId>
<version>1.6.11version>
dependency>
dependencies>
project>provider:
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>dubbo-rootartifactId>
<groupId>com.sisegroupId>
<version>1.0-SNAPSHOTversion>
parent>
<modelVersion>4.0.0modelVersion>
<artifactId>dubbo-provideartifactId>
<properties>
<project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
<java.version>1.8java.version>
properties>
<dependencies>
<dependency>
<artifactId>dubbo-apiartifactId>
<groupId>com.sisegroupId>
<version>1.0-SNAPSHOTversion>
dependency>
dependencies>
project>consumer:
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>dubbo-rootartifactId>
<groupId>com.sisegroupId>
<version>1.0-SNAPSHOTversion>
parent>
<modelVersion>4.0.0modelVersion>
<properties>
<project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
<java.version>1.8java.version>
properties>
<artifactId>dubbo-consumerartifactId>
<dependencies>
<dependency>
<artifactId>dubbo-apiartifactId>
<groupId>com.sisegroupId>
<version>1.0-SNAPSHOTversion>
dependency>
dependencies>
project>api:
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>dubbo-rootartifactId>
<groupId>com.sisegroupId>
<version>1.0-SNAPSHOTversion>
parent>
<modelVersion>4.0.0modelVersion>
<artifactId>dubbo-apiartifactId>
project>这个案例的思路是，我们在api模块中编写rpc服务接口，在provider里面对服务进行实现，最后在consumer里面调用服务进行测试。
api里面的接口如下：
package com.sise.service;
/**
* 作者：idea
* 日期：2018/8/11
* 描述：
*/
public interface UserRpcService {
/**
* 获取用户username的rpc服务
* @param username
* @return
*/
String getUserName(String username) throws InterruptedException;
}关于provider部分的接口实现内容如下所示：
package com.lh.pro.rpc;
import com.sise.service.UserRpcService;
import org.springframework.stereotype.Service;
/**
* 作者：idea
* 日期：2018/8/11
* 描述：用户service服务调度
*/
@Service("userService")
public class UserService implements UserRpcService{
/**
* 返回用户名的服务
* @param username
* @return
*/
public String getUserName(String username) throws InterruptedException {
return username+" hello ! this is app222";
}
}provider模块里面的xml服务配置：
<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="dubbo_provider" />
<dubbo:registry address="zookeeper://127.0.0.1:2181" />
<dubbo:provider proxy="jdk" >dubbo:provider>
<dubbo:protocol name="dubbo" port="20880" />
<dubbo:service interface="com.sise.service.UserRpcService" ref="userService" >
<dubbo:method name="getUserName" timeout="500" retries="2">dubbo:method>
dubbo:service>
beans>spring配置：
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:util="http://www.springframework.org/schema/util" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-4.0.xsd
http://www.springframework.org/schema/util
http://www.springframework.org/schema/util/spring-util-4.0.xsd"
default-autowire="byName">
<aop:aspectj-autoproxy />
<context:component-scan base-package="com.lh.pro" />
<import resource="classpath:dubbo-provider.xml" />
beans>服务开关：
package com.lh.pro.server;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import java.io.IOException;
/**
* 作者：idea
* 日期：2018/8/11
* 描述：provider开关
*/
public class Application {
public static void main(String[] args) throws IOException {
ClassPathXmlApplicationContext context=new ClassPathXmlApplicationContext(new String[]{"application-context.xml"});
context.start();
System.out.println("dubbo的服务生产者1开启了");
//长期开启应用
System.in.read();
}
}记得，开启dubbo之前需要开启zookeeper服务注册点，注册站点开启之后，所有在dubbo里面出现的服务都会被注册到这个位置上边。
开启服务提供者以后，窗口内容大致如下：
我们开启了dubbo里面的服务之后自然就可以开始对于服务的调度方consumer开始编写了。
consumer模块的xml配置如下所示：
<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="dubbo_consumer" />
<dubbo:consumer check="false">dubbo:consumer>
<dubbo:registry protocol="zookeeper" address="zookeeper://127.0.0.1:2181" />
<dubbo:reference id="userService" interface="com.sise.service.UserRpcService" cluster="failsafe" check="false" loadbalance="roundrobin">
dubbo:reference>
beans>spring容器配置：
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:util="http://www.springframework.org/schema/util" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-4.0.xsd
http://www.springframework.org/schema/util
http://www.springframework.org/schema/util/spring-util-4.0.xsd"
default-autowire="byName">
<aop:aspectj-autoproxy />
<context:component-scan base-package="com.lh.consume" />
<import resource="classpath:/dubbo-consume.xml" />
beans>consumer模块部分的代码如下所示：
package com.lh.consume;
import com.sise.service.UserRpcService;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import java.io.IOException;
/**
* 作者：idea
* 日期：2018/7/29
* 描述：
*/
public class ConsumerTest {
public static void main(String[] args) throws InterruptedException {
ClassPathXmlApplicationContext context=new ClassPathXmlApplicationContext(new String[]{"classpath:application-consumer.xml"});
context.start();
UserRpcService userService= (UserRpcService)context.getBean("userService");
System.out.println(userService.getUserName("getUserName test"));
try {
System.in.read();
} catch (IOException e) {
e.printStackTrace();
}
}
}
在这里面，服务的调用者会先去zookeeper里面查找是否有相应的userService这一项服务内容，如果有则会生成一个远程代理对象，在本地进行引用相应服务。
这个时候我们开启消费者进行调用：
好了，一个简单易懂的dubbo入门案例就这样完成了。
下面一章节，我们来讲解如何搭建dubbo的admin管理平台