dubbo简单入门（helloworld例子）

Dubbo现在支持的有三种方式：
1.multicast；
2.zookeeper；
3.redis
下面的Demo使用的是multicast方式。

提供者项目结构：

消费者项目结构：

服务端：

pom.xml配置

<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.minggroupId>
    <artifactId>dubboserverartifactId>
    <version>0.0.1-SNAPSHOTversion>
    <dependencies>
        <dependency>
            <groupId>junitgroupId>
            <artifactId>junitartifactId>
            <version>4.11version>
            <scope>testscope>
        dependency>
        <dependency>
            <groupId>commons-logginggroupId>
            <artifactId>commons-loggingartifactId>
            <version>1.1.1version>
        dependency>
        <dependency>
            <groupId>com.alibabagroupId>
            <artifactId>dubboartifactId>
            <version>2.5.3version>
        dependency>
        <dependency>
            <groupId>org.javassistgroupId>
            <artifactId>javassistartifactId>
            <version>3.15.0-GAversion>
        dependency>
        <dependency>
            <groupId>log4jgroupId>
            <artifactId>log4jartifactId>
            <version>1.2.15version>
            <exclusions>
                <exclusion>
                    <groupId>com.sun.jdmkgroupId>
                    <artifactId>jmxtoolsartifactId>
                exclusion>
                <exclusion>
                    <groupId>com.sun.jmxgroupId>
                    <artifactId>jmxriartifactId>
                exclusion>
                <exclusion>
                    <artifactId>jmsartifactId>
                    <groupId>javax.jmsgroupId>
                exclusion>
                <exclusion>
                    <artifactId>mailartifactId>
                    <groupId>javax.mailgroupId>
                exclusion>
            exclusions>
        dependency>
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-contextartifactId>
            <version>4.1.6.RELEASEversion>
        dependency>

        <dependency>
            <groupId>org.slf4jgroupId>
            <artifactId>slf4j-apiartifactId>
            <version>1.7.5version>
        dependency>
        <dependency>
            <groupId>org.slf4jgroupId>
            <artifactId>slf4j-log4j12artifactId>
            <version>1.6.1version>
        dependency>
        <dependency>
            <groupId>org.apache.zookeepergroupId>
            <artifactId>zookeeperartifactId>
            <version>3.3.6version>
        dependency>
        <dependency>
            <groupId>com.github.adyliugroupId>
            <artifactId>zkclientartifactId>
            <version>2.0version>
        dependency>
        <dependency>
            <groupId>org.jboss.nettygroupId>
            <artifactId>nettyartifactId>
            <version>3.2.0.Finalversion>
        dependency>
        <dependency>
            <groupId>com.101tecgroupId>
            <artifactId>zkclientartifactId>
            <version>0.4version>
        dependency>
    dependencies>
project>  

applicationProvider.xml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="hello-world" />  
<dubbo:registry address="multicast://224.5.6.7:1234"/>   

<dubbo:protocol name="dubbo" port="20880" />          
<bean id="demoService" class="com.ming.dubboserver.HelloWorldImpl" />  
<dubbo:service interface="com.ming.dubboserver.HelloWorld" ref="demoService" executes="10" />  
beans>  

helloworld接口：

package com.ming.dubboserver;

public interface HelloWorld {
    public String hello(String name);
}

helloworld实现类

package com.ming.dubboserver;

public class HelloWorldImpl implements HelloWorld {

    public String hello(String name) {
        name = name + "小明测试";
        return name;

    }

}

服务启动类：

package com.ming.dubboserver;

import java.io.IOException;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class DubboProviderMain {
    public static void main(String[] args) throws IOException {

        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(
                new String[] { "applicationProvider.xml" });
        context.start();
        System.out.println("Press any key to exit.");
        System.in.read();
    }
}

客户端：
pom.xml

<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.minggroupId>
    <artifactId>dubboconsumerartifactId>
    <version>0.0.1-SNAPSHOTversion>
    <name>dubboconsumername>

    <dependencies>
        <dependency>
            <groupId>junitgroupId>
            <artifactId>junitartifactId>
            <version>4.11version>
            <scope>testscope>
        dependency>
        <dependency>
            <groupId>commons-logginggroupId>
            <artifactId>commons-loggingartifactId>
            <version>1.1.1version>
        dependency>
        <dependency>
            <groupId>com.alibabagroupId>
            <artifactId>dubboartifactId>
            <version>2.5.3version>
        dependency>
        <dependency>
            <groupId>org.javassistgroupId>
            <artifactId>javassistartifactId>
            <version>3.15.0-GAversion>
        dependency>
        <dependency>
            <groupId>log4jgroupId>
            <artifactId>log4jartifactId>
            <version>1.2.15version>
            <exclusions>
                <exclusion>
                    <groupId>com.sun.jdmkgroupId>
                    <artifactId>jmxtoolsartifactId>
                exclusion>
                <exclusion>
                    <groupId>com.sun.jmxgroupId>
                    <artifactId>jmxriartifactId>
                exclusion>
                <exclusion>
                    <artifactId>jmsartifactId>
                    <groupId>javax.jmsgroupId>
                exclusion>
                <exclusion>
                    <artifactId>mailartifactId>
                    <groupId>javax.mailgroupId>
                exclusion>
            exclusions>
        dependency>
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-contextartifactId>
            <version>4.1.6.RELEASEversion>
        dependency>
        <dependency>
            <groupId>org.slf4jgroupId>
            <artifactId>slf4j-apiartifactId>
            <version>1.7.5version>
        dependency>
        <dependency>
            <groupId>org.slf4jgroupId>
            <artifactId>slf4j-log4j12artifactId>
            <version>1.6.1version>
        dependency>
        <dependency>
            <groupId>com.github.adyliugroupId>
            <artifactId>zkclientartifactId>
            <version>2.0version>
        dependency>
        <dependency>
            <groupId>org.apache.zookeepergroupId>
            <artifactId>zookeeperartifactId>
            <version>3.3.6version>
        dependency>
        <dependency>
            <groupId>com.minggroupId>
            <artifactId>dubboserverartifactId>
            <version>0.0.1-SNAPSHOTversion>
        dependency>
    dependencies>
project>  

applicationConsumer.xml

<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="consumer-of-helloworld-app" />
    <dubbo:registry address="multicast://224.5.6.7:1234" />
    <dubbo:reference id="demoService" interface="com.ming.dubboserver.HelloWorld" />
beans>   

测试类：

package com.ming.dubboconsumer;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.ming.dubboserver.HelloWorld;
public class ConsumerThd implements Runnable {
    public void run() {
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(
                new String[] { "applicationConsumer.xml" });
        context.start();
        context.getBean("demoService");

         HelloWorld helloWorld = (HelloWorld) context.getBean("demoService");
         String hello = helloWorld.hello("小明");
         System.out.println(hello);
         System.out.println("执行完毕");
    }

    public static void main(String[] args) {
        new Thread(new ConsumerThd()).start();
    }
}

还有一种方式是将Zookeeper作为注册中心，需要下载并安装zookeeper。将配置文件中的注册中心修改为如下即可：

其他代码不用修改，推荐使用zookeeper作为注册中心。如此可以通过Dubbo+注册中心实现分布式服务。服务消费者不用知道服务的具体位置，只要知道注册中心位置即可，消费者只要能消费，不用管消费的是哪的服务，服务提供方与服务消费方解耦。
使用zookeeper注册中心，与dubbo结合，可以查看服务提供者和消费者的信息，将dubbo管理的war包部署到tomcat上，查看服务提供者