使用maven多模块构建dubbo第一个分布式HelloWorld

至于为什么要用maven多模块构建项目，和dubbo是做什么的就不多说了，直接开始。

首先创建一个maven项目作为root模块 命名为mydubbo，并删除其中的src目录（不需要）

除外我们需要Spring，zookeeper的依赖

mydubbo->pom.xml

<?xml version="1.0" encoding="UTF-8"?><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>4.0.0</modelVersion>    <groupId>com</groupId>    <artifactId>mydubbo</artifactId>    <packaging>pom</packaging>    <version>1.0-SNAPSHOT</version>    <properties>        <spring.version>3.2.4.RELEASE</spring.version>    </properties>    <modules>        <module>myProvider</module>        <module>myConsumer</module>        <module>myService</module>    </modules>    <dependencies>        <dependency>            <groupId>com.alibaba</groupId>            <artifactId>dubbo</artifactId>            <version>2.5.3</version>            <exclusions>                <exclusion>                    <groupId>org.springframework</groupId>                    <artifactId>spring</artifactId>                </exclusion>            </exclusions>        </dependency>        <!--dubbo注册中心-->        <dependency>            <groupId>org.apache.zookeeper</groupId>            <artifactId>zookeeper</artifactId>            <version>3.4.6</version>        </dependency>        <!--zookeeper客户端-->        <dependency>            <groupId>com.github.sgroschupf</groupId>            <artifactId>zkclient</artifactId>            <version>0.1</version>        </dependency>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-core</artifactId>            <version>${spring.version}</version>        </dependency>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-context</artifactId>            <version>${spring.version}</version>        </dependency>    </dependencies></project>

然后创建三个maven子模块分别为myService、myProvider、myConsumer

myService:功能接口模块

myProvider:dubbo提供者

myConsumer:dubbo消费者

因为消费者和提供者的功能接口一致，所以都依赖myService模块（myService的项目packing 为 jar）

myProvider->pom.xml

<?xml version="1.0" encoding="UTF-8"?><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>mydubbo</artifactId>        <groupId>com</groupId>        <version>1.0-SNAPSHOT</version>    </parent>    <modelVersion>4.0.0</modelVersion>    <artifactId>myProvider</artifactId>    <dependencies>        <dependency>            <groupId>com</groupId>            <artifactId>myService</artifactId>            <version>1.0-SNAPSHOT</version>        </dependency>    </dependencies></project>

myConsumer->pom.xml

<?xml version="1.0" encoding="UTF-8"?><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>mydubbo</artifactId>        <groupId>com</groupId>        <version>1.0-SNAPSHOT</version>    </parent>    <modelVersion>4.0.0</modelVersion>    <artifactId>myConsumer</artifactId>    <dependencies>        <dependency>            <groupId>com</groupId>            <artifactId>myService</artifactId>            <version>1.0-SNAPSHOT</version>        </dependency>    </dependencies></project>

myService->pom.xml

<?xml version="1.0" encoding="UTF-8"?><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>mydubbo</artifactId>        <groupId>com</groupId>        <version>1.0-SNAPSHOT</version>    </parent>    <modelVersion>4.0.0</modelVersion>    <name>myService</name>    <artifactId>myService</artifactId>    <packaging>jar</packaging></project>

在myService中建立一个Interface，命名为HelloService，具体如下

HelloService.java

package com.service;/** * Created by yuyufeng on 2016/11/16. */public interface HelloService {    String speakHello(String name);}

现在，我们需要install myService这个项目，产生一个可以依赖的jar供其它引用者使用。

myProvider的依赖就有myService产生的jar

现在，开始编写dubbo提供者myProvider的代码

首先，需要提供HelloService的实现

HelloServiceImpl.java

package com.service.impl;import com.service.HelloService;/** * Created by yuyufeng on 2016/11/16. */public class HelloServiceImpl implements HelloService {    public String speakHello(String name) {        return "你好：" + name;    }}

然后使用Spring配置声明暴露服务，建立一个provider.xml 如下

<?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-provider"  />    <!-- 使用multicast广播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.service.HelloService" ref="helloService" />    <!-- 和本地bean一样实现服务 -->    <bean id="helloService" class="com.service.impl.HelloServiceImpl" /></beans>

本次dubbo使用的注册中心为zookeeper，所以需要在本地启动一个zookeeper服务。
最后，我们就可以启动提供者服务了，启动类如下：

package com.service.impl;import org.springframework.context.support.ClassPathXmlApplicationContext;import java.io.IOException;/** * Created by yuyufeng on 2016/11/16. */public class ProviderServer{    public static void main(String[] args) throws IOException {        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("provider.xml");        context.start();

//按任意键退出        System.in.read();    }}

启动之后我们可以在zookeeper注册中心看到我们的服务提供者已经注册在上面

然后，就编写个消费者通过dubbo来调以下远程的服务吧

消费者通过Spring配置引用远程服务spring配置文件如下：

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-consumer"  />    <!-- 使用multicast广播注册中心暴露发现服务地址 -->    <dubbo:registry address="zookeeper://127.0.0.1:2181" />    <!-- 生成远程服务代理，可以和本地bean一样使用demoService -->    <dubbo:reference id="helloService" interface="com.service.HelloService" /></beans>

消费者启动类

ConsumerClient.java

import com.service.HelloService;import org.springframework.context.support.ClassPathXmlApplicationContext;/** * Created by yuyufeng on 2016/11/16. */public class ConsumerClient {    public static void main(String[] args) {        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("consumer.xml");        HelloService helloService = (HelloService) context.getBean("helloService");        String result = helloService.speakHello("yyf");        System.out.println(result);    }}

运行改类，结果如下：

可以看到，远程服务调用成功。