RPC:Dubbo

Start

RPC

Remote Procedure Call 远程过程调用

  • 主要是基于TCP/IP协议，长连接，四个核心的组件：Client,Server,Client Stub，Server Stub
  • 选择RPC框架时的关注点：
    • I/O: 同步／异步，长／短连接
    • 线程调度模型: 单／多线程，线程池，线程调度算法的性能
    • 序列化方式: 可读 (eg: xml,json),二进制(eg: fastjson，jdk自带的序列化）
    • 多语言支持
    • 服务治理（服务发现，监控）
  • 流行的RPC框架：
    • Dubbo（阿里）／ Dubbox（当当）: 基于Java开发，只支持Java的客户端和服务端
    • Motan （新浪）: 基于Java开发
    • Thrift（Facebook －> Apache）: 跨语言的RPC框架，无服务治理
    • Grpc （谷歌): 基于HTTP2.0协议（基于二进制的HTTP协议升级版本），跨语言的RPC框架（应用主要面向移动端）
  • 各RPC框架对比： RPC

Dubbo

  • 一款分布式服务框架
  • 高性能和透明化的RPC远程服务调用方案
  • SOA服务治理方案
  • 提供了三大核心能力：
    • 面向接口的远程方法调用
    • 智能容错和负载均衡
    • 服务自动注册和发现
  • 基于Java开发，只支持Java的客户端和服务端
  • 可以和Spring框架无缝集成

Dubbo 架构

  • 角色：
    • Provider: 暴露服务的服务提供方
    • Consumer: 调用远程服务的服务消费方
    • Registry: 服务注册与发现的注册中心
    • Monitor: 统计服务的调用次数和调用时间的监控中心
    • Container: 服务运行容器
  • 调用关系
    • Container负责启动，加载，运行Provider
    • Provider 启动时向注册中心注册自己提供的服务
    • Consumer 启动时向注册中心订阅自己所需的服务
    • Registry 返回服务提供者地址列表给Consumer (如果有变更，Registry将基于长连接推送变更数据给Consumer)
    • Consumer 从提供者地址列表中，基于软负载均衡算法，选一台提供者进行调用，如果调用失败，再选另一台调用
    • Provider & Consumer 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 Monitor
  • 注：
    • Provider & Consumer & Registory 之间使用的是长连接
    • Provier & Consumer 之间使用非阻塞IO（NIO）通讯
    • Dubbo支持的注册中心有: Multicast,Zookeeper,Redis,Simple，下面的示例均使用Zookeeper

Dubbo Quick Start | dubbo-demo

HelloWorld

dependency

pom.xml

<!-- Dubbo (include spring)-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>dubbo</artifactId>
    <version>2.6.2</version>
</dependency>

<!-- Curator (include zookeeper) -->
<!-- Note: need to change zookeeper version,the beta version zookeeper has issues -->
<dependency>
    <groupId>org.apache.curator</groupId>
    <artifactId>curator-recipes</artifactId>
    <version>4.0.1</version>
    <exclusions>
        <exclusion>
             <groupId>org.apache.zookeeper</groupId>
             <artifactId>zookeeper</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.apache.zookeeper</groupId>
    <artifactId>zookeeper</artifactId>
    <version>3.4.6</version>
    <exclusions>
        <exclusion>
              <groupId>org.slf4j</groupId>
              <artifactId>slf4j-api</artifactId>
        </exclusion>
        <exclusion>
             <groupId>org.slf4j</groupId>
             <artifactId>slf4j-log4j12</artifactId>
        </exclusion>
    </exclusions>
</dependency>

<!-- Junit -->
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
</dependency>

Provider

  • resources/demo-provider.xml

      <?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="demoProvider"/>
      <dubbo:registry address="zookeeper://localhost:2181"/>
      <dubbo:protocol name="dubbo" port="20880"/>
      <dubbo:service interface="com.cj.dubbo.service.DemoService" ref="demoService"/>
      <bean id="demoService" class="com.cj.dubbo.service.DemoServiceImpl"/>

  </beans>

  • Service interface

    package com.cj.dubbo.service;
public interface DemoService {
   String sayHello(String name);
}

  • Service Impl

    package com.cj.dubbo.service;
public class DemoServiceImpl implements DemoService {
  @Override
  public String sayHello(String name) {
      return "Hello "+name;
  }
}

Consumer

  • resources/demo-consumer.xml

    <?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="demoConsumer"/>
  <dubbo:registry address="zookeeper://192.168.99.100:2181"/>
  <dubbo:reference id="demoService" check="false" interface="com.cj.dubbo.service.DemoService"/>
</beans>

  • Service interface

    package com.cj.dubbo.service;
public interface DemoService {
   String sayHello(String name);
}

Test

package com.cj.dubbo;
import java.io.IOException;
import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.cj.dubbo.consumer.HelloConsumerService;
import com.cj.dubbo.service.DemoService;
import com.cj.dubbo.service.HelloService;

public class DemoDubboTest {
    @Test
    public void runDemoProvider() throws IOException {
        System.setProperty("java.net.preferIPv4Stack", "true");
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[]{"demo-provider.xml"});
        context.start();
        System.out.println("Provider started.");
        System.in.read(); // press any key to exit
    }

    @Test
    public void runDemoConsumer() {
        // System.setProperty("java.net.preferIPv4Stack", "true");
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[]{"demo-consumer.xml"});
        context.start();
        DemoService demoService = (DemoService) context.getBean("demoService"); // obtain proxy object for remote invocation
        String hello = demoService.sayHello("world"); // execute remote invocation
        System.out.println(hello); // show the result
    }
}

Check zookeeper

[zk: zk01:2181(CONNECTED) 9] ls /dubbo
[com.cj.dubbo.service.DemoService]
[zk: zk01:2181(CONNECTED) 10] ls /dubbo/com.cj.dubbo.service.DemoService
[consumers, configurators, routers, providers]

Demo

Provider (SpringBoot)

  1. pom.xml

     <!-- springboot -->
 <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-web</artifactId>
 </dependency>
 <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-test</artifactId>
     <scope>test</scope>
 </dependency>

 <!-- springboot dubbo -->
 <!-- <dependency>
     <groupId>com.alibaba.spring.boot</groupId>
     <artifactId>dubbo-spring-boot-starter</artifactId>
     <version>2.0.0</version>
 </dependency> -->

 <!-- Dubbo (include spring) -->
 <dependency>
     <groupId>com.alibaba</groupId>
     <artifactId>dubbo</artifactId>
     <version>2.6.2</version>
 </dependency>

 <!-- Curator (include zookeeper) -->
 <!-- Note: need to change zookeeper version,the beta version zookeeper has issues -->
 <dependency>
     <groupId>org.apache.curator</groupId>
     <artifactId>curator-recipes</artifactId>
     <version>4.0.1</version>
     <exclusions>
         <exclusion>
              <groupId>org.apache.zookeeper</groupId>
              <artifactId>zookeeper</artifactId>
         </exclusion>
     </exclusions>
 </dependency>
 <dependency>
     <groupId>org.apache.zookeeper</groupId>
     <artifactId>zookeeper</artifactId>
     <version>3.4.6</version>
     <exclusions>
         <exclusion>
               <groupId>org.slf4j</groupId>
               <artifactId>slf4j-api</artifactId>
         </exclusion>
         <exclusion>
              <groupId>org.slf4j</groupId>
              <artifactId>slf4j-log4j12</artifactId>
         </exclusion>
     </exclusions>
 </dependency>

  2. Configure

    • resources/log4j.properties
        ###set log levels###
  log4j.rootLogger=warn, 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

    • resources/provider.xml

        <?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="helloProvider"/>
      <dubbo:registry address="zookeeper://localhost:2181"/>
      <dubbo:protocol name="dubbo" port="20881"/>
      <dubbo:service interface="com.cj.dubbo.service.HelloService"  ref="helloService"/>

  </beans>

    • Config: import the provider.xml

        package com.cj.dubbo.config;
  import org.springframework.context.annotation.Configuration;
  import org.springframework.context.annotation.ImportResource;

  @Configuration
  @ImportResource(locations={"classpath:provider.xml"})
  public class ProviderConfig {
  }

  3. Service

    • interface
        package com.cj.dubbo.service;
  public interface HelloService {
      public String sayHello(String name);
  }

    • implement

        package com.cj.dubbo.provider;
  import org.springframework.stereotype.Component;
  import com.cj.dubbo.service.HelloService;

  @Component("helloService")
  public class HelloServiceImpl implements HelloService {
      @Override
      public String sayHello(String name) {
          return "Hello, " + name + " (from Spring Boot)";
      }
  }

  4. Start

     package com.cj.dubbo;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;

 @SpringBootApplication
 public class HelloProviderApplication {
     public static void main(String[] args) {
         SpringApplication.run(HelloProviderApplication.class,args);
         System.out.println("Start Application");
     }
 }

Consumer (Spring)

  1. pom.xml

     <!-- Curator(include Zookeeper) -->
 <dependency>
     <groupId>org.apache.curator</groupId>
     <artifactId>curator-recipes</artifactId>
     <version>4.0.1</version>
 </dependency>

 <!-- Dubbo (include Spring) -->
 <dependency>
     <groupId>com.alibaba</groupId>
     <artifactId>dubbo</artifactId>
     <version>2.6.2</version>
 </dependency>

 <!-- Junit -->
 <dependency>
     <groupId>junit</groupId>
     <artifactId>junit</artifactId>
     <version>4.12</version>
 </dependency>

  2. Configure: resource/hello-consumer.xml

     <?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="helloConsumer"/>
     <dubbo:registry address="zookeeper://localhost:2181"/>
     <dubbo:reference id="helloService" check="false"  interface="com.cj.dubbo.service.HelloService"/>

     <bean id="helloConsumerService" class="com.cj.dubbo.consumer.HelloConsumerService">
         <property name="helloService" ref="helloService"/>
     </bean>
 </beans>

  3. Service

    • interface (same with Provider service interface)
        package com.cj.dubbo.service;
  public interface HelloService {
      public String sayHello(String name);
  }

    • Call the provided Service

        package com.cj.dubbo.consumer;
  import com.cj.dubbo.service.HelloService;

  public class HelloConsumerService {
      private HelloService helloService;
      public HelloService getHelloService() {
          return helloService;
      }
      public void setHelloService(HelloService helloService) {
          this.helloService = helloService;
      }
      public void printSay(String name) {
          if(helloService==null)
              System.out.println("Can't get helloService!");
          System.out.println(helloService.sayHello(name));
      }
  }

  4. Test

     public class DemoDubboTest {
     @Test
     public void runHelloConsumer() {
         // System.setProperty("java.net.preferIPv4Stack", "true");
         ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[]{"hello-consumer.xml"});
         context.start();
         HelloService helloService = (HelloService) context.getBean("helloService"); // obtain proxy object for remote invocation
         String hello=helloService.sayHello("Girl"); // execute remote invocation
         System.out.println(hello);                    // show the result

         System.out.println("---- Consume HelloService ----");
         HelloConsumerService consumer=context.getBean(HelloConsumerService.class);
         consumer.printSay("Boy");

     }
 }

  5. Check zookeeper

     [zk: zk01:2181(CONNECTED) 9] ls /dubbo
 [com.cj.dubbo.service.DemoService, com.cj.dubbo.service.HelloService]

 [zk: zk01:2181(CONNECTED) 18] ls /dubbo/com.cj.dubbo.service.HelloService      
 [consumers, configurators, routers, providers]

 [zk: zk01:2181(CONNECTED) 19] ls /dubbo/com.cj.dubbo.service.HelloService/providers
 [dubbo%3A%2F%2F192.168.31.78%3A20881%2Fcom.cj.dubbo.service.HelloService%3Fanyhost%3Dtrue%26application%3DhelloProvider%26dubbo%3D2.6.2%26generic%3Dfalse%26interface%3Dcom.cj.dubbo.service.HelloService%26methods%3DsayHello%26pid%3D1359%26side%3Dprovider%26timestamp%3D1549812635667]

 [zk: zk01:2181(CONNECTED) 20] ls /dubbo/com.cj.dubbo.service.HelloService/consumers
 []

Reference

My demo: dubbo-demo

什么是Dubbo

dubbo的详细介绍

dubbo从入门到精通