Dubbo-概述，示例Demo

清疚 2022-06-09 00:28 199阅读 0赞

因为公司要使用dubbo,所以学习一下。随着互联网的发展，程序架构由最先看是的单一架构，到垂直应用架构，再到分布式服务架构（RPC），最后到流式计算架构（SOA）。而dubbo最主要的就是应用于，当服务越来越多，服务URL配置管理也越来越复杂，单点压力越来越大。以及服务之间的依赖关系错综复杂，服务调用量越来越大，那么这个服务需要多少机器支撑，该什么时候加机器呢？

dubbo分为服务提供者，服务消费者，以及监视器和注册中心。服务提供者在启动服务的同时，会注册到注册中心。服务消费者也会注册到注册中心，当注册中心的服务者列表发生变更时，注册中心会推送到消费者，注册中心与消费者之间是长连接。消费者每次调用服务者的服务时是不需要经过注册中心的，而是直接调用服务者的接口。服务消费者和提供者，在内存中累计调用次数和调用时间，定时每分钟发送一次统计数据到监控中心。监控中心会将这些数据形成报表展示，发送给调度中心。![20170823105628414][]

接下面参照官网demo在本地写了一个小demo.

第一步，定义服务接口

package org.lic.dubbo.demo;
    
    public interface DemoService {
    
    	String sayHello(String name); 
    }

这个接口是在服务提供者和服务消费者之间共享的，所以我把它单独放到了一个项目里面打包。下面是pom.xml文件内容

第二步，创建服务提供者。  
首先看pom.xml文件内容

<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/maven-v4_0_0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>org.lic</groupId>
      <artifactId>dubbo-provider</artifactId>
      <packaging>war</packaging>
      <version>0.0.1-SNAPSHOT</version>
      <name>dubbo-provider Maven Webapp</name>
      <url>http://maven.apache.org</url>
      
      <properties>
        <spring.version>4.2.5.RELEASE</spring.version>
    	<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    	<jdk.version>1.7</jdk.version>
      </properties>
      
      <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>  
            <dependency>  
                <groupId>com.github.sgroschupf</groupId>  
                <artifactId>zkclient</artifactId>  
                <version>0.1</version>  
            </dependency>  
              
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-core</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-beans</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-context</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-jdbc</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-web</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-webmvc</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-aop</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-tx</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-orm</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-context-support</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-test</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-jms</artifactId>  
                <version>${spring.version}</version>  
            </dependency>
    	
        <dependency>
          <groupId>org.lic</groupId>
          <artifactId>dubboDemo</artifactId>
          <version>0.0.1-SNAPSHOT</version>
        </dependency>  
      
        <dependency>
          <groupId>junit</groupId>
          <artifactId>junit</artifactId>
          <version>3.8.1</version>
          <scope>test</scope>
        </dependency>
      </dependencies>
      
      <build>
      	  <finalName>${project.artifactId}</finalName>
    	  <plugins>
    	    <plugin>
    	      <groupId>org.apache.maven.plugins</groupId>
    	      <artifactId>maven-compiler-plugin</artifactId>
    	      <configuration>
    	        <source>1.7</source>
    	        <target>1.7</target>
    	      </configuration>
    	    </plugin>
    	  </plugins>
      </build>
    </project>

这里我引入了dubbo包，已经先关以来包。还有服务接口。如果在一个项目里面引用自己创建的另外一个项目，只需要在dependecy里面把groupId, artifactId，version换成项目对应的就可以了，如

<dependency>
          <groupId>org.lic</groupId>
          <artifactId>dubboDemo</artifactId>
          <version>0.0.1-SNAPSHOT</version>
        </dependency>

接下来我们实现这个服务接口

package org.lic.dubbo.demo.provider;
    
    import org.lic.dubbo.demo.DemoService;
    
    public class DemoServiceImpl implements DemoService{
    
    	public String sayHello(String name){
    		return "Hello," + name;
    	}
    }

官方文档说对消息放隐藏实现，这想到的方式就是把接口单独成项目，打包共享。不知道大家有没有其他想法。

接着使用spring配置声明暴露服务

<?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">
    
        
        <dubbo:application name="dubbo-provide"  />
    
        
        <dubbo:registry address="multicast://224.5.6.7:1234" />
        
        
        
    
        
        <dubbo:protocol name="dubbo" port="20880" />
        
        
        
    
        
        <dubbo:service interface="org.lic.dubbo.demo.DemoService" ref="demoService" />
    
        
        <bean id="demoService" class="org.lic.dubbo.demo.provider.DemoServiceImpl" />
    
    </beans>

这里可以看到我把zookeeper注册中心暴露服务地址注释掉了，官方建议是dubbo与zookeeper一起使用的。zookeeper是一个分布式的协调服务，为分布式提供了配置微信，名字服务，分布式同步，组服务等这些功能。我们先做做简单的，不加入zookeeper.

还要注意一点

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

这里的ip是应该填D类IP地址，D类地址多用于广播（Multicast）,D类IP地址第一个字节以“1110”开始，它是一个专门保留的地址。它并不指向特定的网络，目前这一类地址呗用在多点广播（Multicast）中。多点广播地址用来一次寻址一组计算机，它标志共享同一协议的一组计算机。地址范围是224.0.0.1-239.255.255.254，所以我们这里能填写的地址范围也是这个。

最后是启动方法

package org.lic.dubbo.demo.provider;
    
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    public class Provider {
    
    	public static void main(String[] args) throws Exception{
    		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[] {"spring/provider.xml"});
    		context.start();
    		System.out.println("提供者服务已注册成功");
    		System.out.println("请按任意键取消提供者服务");
    		System.in.read(); // 按任意键退出
    	}
    }

直接启动，可以看到控制台输出

log4j:WARN No appenders could be found for logger (org.springframework.core.env.StandardEnvironment).
    log4j:WARN Please initialize the log4j system properly.
    提供者服务已注册成功
    请按任意键取消提供者服务

第三步，创建服务消费者

还是一样，先看pom.xml，和服务提供者的一样

<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/maven-v4_0_0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>org.lic</groupId>
      <artifactId>dubbo-consumer</artifactId>
      <packaging>war</packaging>
      <version>0.0.1-SNAPSHOT</version>
      <name>dubbo-consumer Maven Webapp</name>
      <url>http://maven.apache.org</url>
      
      <properties>
        <spring.version>4.2.5.RELEASE</spring.version>
    	<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    	<jdk.version>1.7</jdk.version>
      </properties>
      
      <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>  
              
            <dependency>  
                <groupId>com.github.sgroschupf</groupId>  
                <artifactId>zkclient</artifactId>  
                <version>0.1</version>  
            </dependency>  
              
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-core</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-beans</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-context</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-jdbc</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-web</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-webmvc</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-aop</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-tx</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-orm</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-context-support</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-test</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
            <dependency>  
                <groupId>org.springframework</groupId>  
                <artifactId>spring-jms</artifactId>  
                <version>${spring.version}</version>  
            </dependency>  
      
        <dependency>
          <groupId>org.lic</groupId>
          <artifactId>dubboDemo</artifactId>
          <version>0.0.1-SNAPSHOT</version>
        </dependency>
      
        <dependency>
          <groupId>junit</groupId>
          <artifactId>junit</artifactId>
          <version>3.8.1</version>
          <scope>test</scope>
        </dependency>
      </dependencies>
      
      
      <build>
      	  <finalName>${project.artifactId}</finalName>
    	  <plugins>
    	    <plugin>
    	      <groupId>org.apache.maven.plugins</groupId>
    	      <artifactId>maven-compiler-plugin</artifactId>
    	      <configuration>
    	        <source>1.7</source>
    	        <target>1.7</target>
    	      </configuration>
    	    </plugin>
    	  </plugins>
      </build>
    </project>

再使用spring配置引用远程服务

最后是启动类

package org.lic.dubbo.demo.consumer;
    
    import org.lic.dubbo.demo.DemoService;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    public class Consumer {
    
    	public static void main(String[] args) throws Exception{
    		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[] {"spring/consumer.xml"});
    		context.start();
    		
    		DemoService demoService = (DemoService)context.getBean("demoService"); // 获取远程服务代理
    		String hello = demoService.sayHello("world"); // 执行远程方法
    		System.out.println(hello); // 显示调用结果
    	}
    }

可以从控制台看到输出

log4j:WARN No appenders could be found for logger (org.springframework.core.env.StandardEnvironment).
    log4j:WARN Please initialize the log4j system properly.
    Hello,world

这个是demo代码下载地址 http://download.csdn.net/download/licheng989/9946140，欢迎大家扔砖。

[20170823105628414]: /images/20220609/f4961fa5ba094f8c8a97ebc6cc11e300.png