dubbo初学，快速体验

本篇是基于spring框架的XML配置开发的dubbo应用程序，开发工具intellij idea，旨在对dubbo的快速理解和上手。

废话不多说，代码撸起来！！！

1.首先，新建一个maven工程，命名为dubbodemo，右击dubbodemo，新建module，如图

建立三个子项目，分别命名为dubbo-demo-api，dubbo-demo-consumer，dubbo-demo-provider

2.根目录下pom.xml文件配置如下

 <?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.nari</groupId>
     <artifactId>dubbo-demo</artifactId>
     <packaging>pom</packaging>
     <version>1.0-SNAPSHOT</version>
     <modules>
         <module>dubbo-demo-api</module>
         <module>dubbo-demo-provider</module>
         <module>dubbo-demo-consumer</module>
     </modules>

     <dependencies>
         <dependency>
             <groupId>log4j</groupId>
             <artifactId>log4j</artifactId>
             <version>1.2.17</version>
         </dependency>
         <dependency>
             <groupId>org.slf4j</groupId>
             <artifactId>slf4j-api</artifactId>
             <version>1.7.5</version>
         </dependency>
         <dependency>
             <groupId>org.slf4j</groupId>
             <artifactId>slf4j-log4j12</artifactId>
             <version>1.7.5</version>
         </dependency>

         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
             <version>3.3.2</version>
         </dependency>

         <dependency>
             <groupId>commons-io</groupId>
             <artifactId>commons-io</artifactId>
             <version>2.4</version>
         </dependency>

         <!-- spring -->
         <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-context</artifactId>
             <version>5.1.5.RELEASE</version>
         </dependency>

         <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-core</artifactId>
             <version>5.1.5.RELEASE</version>
         </dependency>

         <!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-beans</artifactId>
             <version>5.1.5.RELEASE</version>
         </dependency>

         <!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-web</artifactId>
             <version>5.1.5.RELEASE</version>
         </dependency>

         <!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-webmvc</artifactId>
             <version>5.1.5.RELEASE</version>
         </dependency>

         <!-- https://mvnrepository.com/artifact/org.springframework/spring-test -->
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-test</artifactId>
             <version>5.1.5.RELEASE</version>
             <scope>test</scope>
         </dependency>

         <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-jdbc</artifactId>
             <version>5.1.5.RELEASE</version>
         </dependency>

         <!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-tx</artifactId>
             <version>5.1.5.RELEASE</version>
         </dependency>

         <!-- https://mvnrepository.com/artifact/org.springframework/spring-oxm -->
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-oxm</artifactId>
             <version>5.1.5.RELEASE</version>
         </dependency>

         <!-- https://mvnrepository.com/artifact/org.apache.dubbo/dubbo -->
         <dependency>
             <groupId>org.apache.dubbo</groupId>
             <artifactId>dubbo</artifactId>
             <version>2.7.0</version>
         </dependency>
         <!--<dependency>
             <groupId>org.apache.zookeeper</groupId>
             <artifactId>zookeeper</artifactId>
             <version>3.4.13</version>
         </dependency>
         <dependency>
             <groupId>com.101tec</groupId>
             <artifactId>zkclient</artifactId>
             <version>0.8</version>
         </dependency>-->
     </dependencies>

 </project>

3.服务的提供方提供接口，如图所示，在dubbo-demo-api中新建一个interface接口，DemoService

 package com.nari.api;

 public interface DemoService {

     String sayHello(String name);

 }

pom文件如下

 <?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>dubbo-demo</artifactId>
         <groupId>com.nari</groupId>
         <version>1.0-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>

     <artifactId>dubbo-demo-api</artifactId>

 </project>

4.dubbo-demo-provider目录下，引入对dubbo-demo-api依赖。新建DemoServiceImpl类实现DemoService接口，如图所示

pom.xml文件如下

 <?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>dubbo-demo</artifactId>
         <groupId>com.nari</groupId>
         <version>1.0-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>

     <artifactId>dubbo-demo-provider</artifactId>

     <dependencies>
         <dependency>
             <artifactId>dubbo-demo-api</artifactId>
             <groupId>com.nari</groupId>
             <version>1.0-SNAPSHOT</version>
         </dependency>

     </dependencies>

 </project>

DemoServiceImpl.java

 package com.nari.provider;

 import com.nari.api.DemoService;

 public class DemoServiceImpl implements DemoService {
     public String sayHello(String name) {
         return "hello " + name;
     }
 }

在resources目录下新建provider.xml文件，使用广播multicast作为注册中心，优点是易于操作，不用做其他配置。dubbo服务端口为20880，<dubbo:service>暴露服务端口demoService

 <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:dubbo="http://dubbo.apache.org/schema/dubbo"
        xmlns="http://www.springframework.org/schema/beans"
        xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
        http://dubbo.apache.org/schema/dubbo http://dubbo.apache.org/schema/dubbo/dubbo.xsd">

     <!-- provider's application name, used for tracing dependency relationship -->
     <dubbo:application name="demo-provider">
         <dubbo:parameter key="qos.enable" value="true" />
         <dubbo:parameter key="qos.accept.foreign.ip" value="false" />
         <dubbo:parameter key="qos.port" value="22222" />
     </dubbo:application>
     <!-- use multicast registry center to export service -->
     <dubbo:registry address="multicast://224.5.6.7:1234" check="false"/>
     <!-- use dubbo protocol to export service on port 20880 -->
     <dubbo:protocol name="dubbo" port="20880"/>
     <!-- service implementation, as same as regular local bean -->
     <bean id="demoService" class="com.nari.provider.DemoServiceImpl"/>
     <!-- declare the service interface to be exported -->
     <dubbo:service interface="com.nari.api.DemoService" ref="demoService"/>
 </beans>

新建provider.java，读取xml配置文件，代码如下

 package com.nari.provider.main;

 import org.springframework.context.support.ClassPathXmlApplicationContext;

 import java.io.IOException;

 public class Provider {

     public static void main(String[] args) {
         try {
             System.setProperty("java.net.preferIPv4Stack", "true");
             ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[]{"META-INF/spring/provider.xml"});
             context.start();
             System.out.println("Provider started....");
             System.in.read();
         }catch (IOException e){
             e.printStackTrace();
         }
     }

 }

在resources目录下引入log4j.properties，开启日志功能

###set log levels###
log4j.rootLogger=info, stdout
###output to the console###
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=[%d{dd/MM/yy hh:mm:ss:sss z}] %t %5p %c{2}: %m%n

5.dubbo-demo-consumer目录下，对暴露的接口调用，获取服务，文件目录如下

pom.xml文件配置如下

 <?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>dubbo-demo</artifactId>
         <groupId>com.nari</groupId>
         <version>1.0-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>

     <artifactId>dubbo-demo-consumer</artifactId>

     <dependencies>
         <dependency>
             <artifactId>dubbo-demo-provider</artifactId>
             <groupId>com.nari</groupId>
             <version>1.0-SNAPSHOT</version>
         </dependency>
     </dependencies>

 </project>

在resources目录下新建consumer.xml文件，声明注册中心为multicast，地址与provider.xml文件中保持一致，<dubbo:reference>引入接口，调用服务。添加log4j.properties日志文件。

 <?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:dubbo="http://dubbo.apache.org/schema/dubbo"
        xmlns="http://www.springframework.org/schema/beans"
        xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
        http://dubbo.apache.org/schema/dubbo http://dubbo.apache.org/schema/dubbo/dubbo.xsd">

     <!-- consumer's application name, used for tracing dependency relationship (not a matching criterion),
     don't set it same as provider -->
     <dubbo:application name="demo-consumer">
         <dubbo:parameter key="qos.enable" value="true" />
         <dubbo:parameter key="qos.accept.foreign.ip" value="false" />
         <dubbo:parameter key="qos.port" value="33333" />
     </dubbo:application>
     <!-- use multicast registry center to discover service -->
     <dubbo:registry address="multicast://224.5.6.7:1234" check="false"/>
     <!-- generate proxy for the remote service, then demoService can be used in the same way as the
     local regular interface -->
     <dubbo:reference id="demoService" check="false" interface="com.nari.api.DemoService"/>
     <!--<dubbo:consumer check="false" />-->
 </beans>

新建consumer.java文件，context上下文获取bean服务，调用其方法

 package com.nari.consumer.main;

 import com.nari.api.DemoService;
 import org.springframework.context.support.ClassPathXmlApplicationContext;

 public class Consumer {

     public static void main(String[] args) {
         ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[]{"META-INF/spring/consumer.xml"});
         context.start();
         DemoService demoService = (DemoService) context.getBean("demoService");
         String hello = demoService.sayHello("zhangsan");
         System.out.println(hello);
     }

 }

6.至此，工程搭建完成，先启动Provider.main()方法，服务的提供方提供服务，如图，打印结果如下

再启动Consumer.main()方法，服务的消费方成功获取到服务，打印结果如下：