dubbo实战之一：准备和初体验

《dubbo实战》系列的父工程

为了方便管理《dubbo实战》系列的代码和依赖库版本的管理，这里创建名为dubbopractice的父maven工程，整个系列的后续源码都会作为它的子工程；

dubbopractice的pom.xml内容如下：

<?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">

<module>practiceinterface</module>

<module>helloxmldirectprovider</module>

<module>helloxmldirectconsumer</module>

<module>springbootzkprovider</module>

<module>springbootzkconsumer</module>

<module>springbootmulticastprovider</module>

<module>springbootmulticastconsumer</module>

</modules>

<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

<maven.compiler.source>1.8</maven.compiler.source>

<maven.compiler.target>1.8</maven.compiler.target>

<java.version>1.8</java.version>

<dubbo.version>2.7.6</dubbo.version>

<springboot.version>2.3.3.RELEASE</springboot.version>

</properties>

<groupId>com.bolingcavalry</groupId>

<artifactId>dubbopractice</artifactId>

<version>1.0-SNAPSHOT</version>

<groupId>org.apache.dubbo</groupId>

<artifactId>dubbo-dependencies-bom</artifactId>

<version>${dubbo.version}</version>

<scope>import</scope>

</dependency>

<groupId>io.netty</groupId>

<artifactId>netty-all</artifactId>

<version>4.1.25.Final</version>

</dependency>

<groupId>org.apache.dubbo</groupId>

<artifactId>dubbo</artifactId>

<version>${dubbo.version}</version>

</dependency>

<groupId>org.apache.dubbo</groupId>

<artifactId>dubbo-dependencies-zookeeper</artifactId>

<version>${dubbo.version}</version>

</dependency>

<groupId>org.apache.dubbo</groupId>

<artifactId>dubbo-spring-boot-starter</artifactId>

<version>${dubbo.version}</version>

</dependency>

<groupId>org.apache.dubbo</groupId>

<artifactId>dubbo-registry-multicast</artifactId>

<version>${dubbo.version}</version>

</dependency>

<groupId>org.apache.zookeeper</groupId>

<artifactId>zookeeper</artifactId>

</dependency>

<groupId>com.github.sgroschupf</groupId>

<artifactId>zkclient</artifactId>

</dependency>

<groupId>org.projectlombok</groupId>

<artifactId>lombok</artifactId>

</dependency>

<groupId>com.fasterxml.jackson.core</groupId>

<artifactId>jackson-databind</artifactId>

<scope>compile</scope>

</dependency>

<groupId>com.fasterxml.jackson.datatype</groupId>

<artifactId>jackson-datatype-jdk8</artifactId>

<scope>compile</scope>

</dependency>

<scope>compile</scope>

</dependency>

<groupId>commons-io</groupId>

<artifactId>commons-io</artifactId>

<scope>compile</scope>

</dependency>

<groupId>org.apache.commons</groupId>

<artifactId>commons-lang3</artifactId>

<scope>compile</scope>

</dependency>

<groupId>io.springfox</groupId>

<artifactId>springfox-swagger2</artifactId>

</dependency>

<groupId>io.springfox</groupId>

<artifactId>springfox-swagger-ui</artifactId>

</dependency>

</dependencies>

</dependencyManagement>

</project>

《dubbo实战》系列的二方库

涉及到多个工程之间的服务调用，因此要有个工程保存公用的数据结构、接口定义等，因此新建名为practiceinterface的子工程；

practiceinterface工程的pom.xml内容如下，非常简单：

<?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">

<artifactId>dubbopractice</artifactId>

<groupId>com.bolingcavalry</groupId>

<version>1.0-SNAPSHOT</version>

</parent>

<groupId>com.bolingcavalry</groupId>

<artifactId>practiceinterface</artifactId>

<version>1.0-SNAPSHOT</version>

<name>practiceinterface</name>

<description>Beans of all app</description>

</project>

此工程目前只有一个接口定义，后面多个子工程都会用到：

package com.bolingcavalry.dubbopractice.service;

public interface DemoService {

String sayHello(String name);

}

编码(服务提供方)

先创建提供服务的工程helloxmldirectprovider，一共要创建6个文件，创建顺序和功能如下表：

创建顺序文件名作用

1 pom.xml 工程的pom文件

2 src/main/java/com/bolingcavalry/helloxmldirectprovider/ProviderApplication.java 启动类

3 src/main/java/com/bolingcavalry/helloxmldirectprovider/service/impl/DemoServiceImpl.java 提供具体的服务

4 src/main/resources/log4j.properties 日志配置文件

5 src/main/resources/dubbo.properties dubbo配置文件

6 src/main/resources/spring/dubbo-provider.xml spring的bean配置

完整的文件位置如下图：

在这里插入图片描述

接下来逐个创建上述内容；

创建名为helloxmldirectprovider的子工程，pom.xml内容如下，可见刚才新建的二方库practiceinterface也被依赖了：

<?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">

<artifactId>dubbopractice</artifactId>

<groupId>com.bolingcavalry</groupId>

<version>1.0-SNAPSHOT</version>

</parent>

<groupId>com.bolingcavalry</groupId>

<artifactId>helloxmldirectprovider</artifactId>

<version>1.0-SNAPSHOT</version>

<groupId>com.bolingcavalry</groupId>

<artifactId>practiceinterface</artifactId>

<version>${project.version}</version>

</dependency>

<groupId>org.apache.dubbo</groupId>

<artifactId>dubbo</artifactId>

</dependency>

<groupId>org.projectlombok</groupId>

<artifactId>lombok</artifactId>

</dependency>

</dependency>

</dependencies>

</project>

编写启动类ProviderApplication.java，可见就是个普通的后台程序，加载spring配置做初始化：

package com.bolingcavalry.helloxmldirectprovider;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class ProviderApplication {

public static void main(String[] args) throws Exception {

ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("spring/dubbo-provider.xml");

context.start();

System.in.read();

}

编写提供具体服务的业务实现类DemoServiceImpl.java，只是个简单的接口实现类而已：

package com.bolingcavalry.helloxmldirectprovider.service.impl;

import com.bolingcavalry.dubbopractice.service.DemoService;

import lombok.extern.slf4j.Slf4j;

import org.apache.dubbo.rpc.RpcContext;

@Slf4j

public class DemoServiceImpl implements DemoService {

@Override

public String sayHello(String name) {

log.info("Hello " + name + ", request from consumer: " + RpcContext.getContext().getRemoteAddress());

try {

Thread.sleep(1000);

} catch (InterruptedException e) {

e.printStackTrace();

}

return "Hello " + name + ", response from provider: " + RpcContext.getContext().getLocalAddress();

}

日志配置文件log4j.properties，内容如下：

###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

在同样位置创建dubbo配置文件dubbo.properties，内容很简单只有qos的端口设置，用于支持telnet命令：

dubbo.application.qos.port=22222

在resources目录下新建文件夹spring，在此文件夹下创建文件dubbo-provider.xml，要重点关注的是dubbo:registry的配置，其address属性值为multicast://224.5.6.7:1234，代表当前服务通过广播让消费者获得自身信息：

<?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">

<dubbo:application name="demo-provider"/>

<dubbo:registry address="multicast://224.5.6.7:1234" />

<dubbo:service interface="com.bolingcavalry.dubbopractice.service.DemoService" ref="demoService"/>

</beans>

至此，服务提供方编码完成，直接在IDEA上运行ProviderApplication类即可启动服务，启动成功后的日志输出如下图：

在这里插入图片描述

编码(服务消费方)

现在网络上已经有了服务，接下来创建一个消费该服务的工程helloxmldirectconsumer，一共要创建5个文件，创建顺序和功能如下表：

创建顺序文件名作用

1 pom.xml 工程的pom文件

2 src/main/java/com/bolingcavalry/helloxmldirectconsumer/ConsumerApplication.java 启动、调用远端服务、再结束自身进程

3 src/main/resources/log4j.properties 日志配置文件

4 src/main/resources/dubbo.properties dubbo配置文件

5 src/main/resources/spring/dubbo-consumer.xml spring的bean配置

完整的文件位置如下图：

在这里插入图片描述

接下来逐个创建上述文件；

创建名为helloxmldirectconsumer的子工程，pom.xml内容如下，可见刚才新建的二方库practiceinterface也被依赖了：

<?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">

<artifactId>dubbopractice</artifactId>

<groupId>com.bolingcavalry</groupId>

<version>1.0-SNAPSHOT</version>

</parent>

<groupId>com.bolingcavalry</groupId>

<artifactId>helloxmldirectconsumer</artifactId>

<version>1.0-SNAPSHOT</version>

<groupId>com.bolingcavalry</groupId>

<artifactId>practiceinterface</artifactId>

<version>${project.version}</version>

</dependency>

<groupId>org.apache.dubbo</groupId>

<artifactId>dubbo</artifactId>

</dependency>

<groupId>org.projectlombok</groupId>

<artifactId>lombok</artifactId>

</dependency>

</dependency>

</dependencies>

</project>

编写唯一的java文件ConsumerApplication.java，里面用了最简单的方法初始化spring环境，然后取得服务实例，执行过方法后结束进程：

package com.bolingcavalry.helloxmldirectconsumer;

import com.bolingcavalry.dubbopractice.service.DemoService;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class ConsumerApplication {

public static void main(String[] args) throws Exception {

ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("spring/dubbo-consumer.xml");

context.start();

DemoService demoService = context.getBean("demoService", DemoService.class);

String hello = demoService.sayHello("world1");

System.out.println("result: " + hello);

}

日志配置文件log4j.properties，内容如下：

###set log levels###

log4j.rootLogger=info, stdout

###output to 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

在同样位置创建dubbo配置文件dubbo.properties，内容很简单只有qos的端口设置，用于支持telnet命令，本例中是用不上的，因为远程调用后进程就会结束：

dubbo.application.qos.port=33333

在resources目录下新建文件夹spring，在此文件夹下创建文件dubbo-consumer.xml，要重点关注的是dubbo:registry的配置，其address属性值为multicast://224.5.6.7:1234?unicast=false，代表当前服务通过广播让消费者获得自身信息，unicast=false表示多个消费者都能收到广播：

<?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">

<dubbo:application name="demo-consumer"/>

<dubbo:registry address="multicast://224.5.6.7:1234?unicast=false"/>

<dubbo:reference id="demoService" check="false" interface="com.bolingcavalry.dubbopractice.service.DemoService" timeout="2000"/>

</beans>

上面的dubbo-consumer.xml中还有一处要注意，就是dubbo:reference的timeout属性，这是远程调用的超时时间，此处设置为2秒，要注意的是前面helloxmldirectprovider提供的服务延时了1秒才返回，所以这里设置不能低于1秒；

至此，服务消费方编码完成，直接在IDEA上运行ConsumerApplication类即可启动，如下图，红框中就是远程调用helloxmldirectprovider服务返回的内容：

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dubbo实战之一：准备和初体验

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