dobbo

写了好多博客，觉得应该以一种通俗的方式去阐述相关案例更贴切一些

dubbo是一款非常优秀的分布式开发框架，尤其是传统项目改造成分布式开发部署项目时，改造成本极低，可用性，一致性，容错性较好

下面开始入门案例，本次案例以官方给出的dubbo-demo 作为入门案例，较为便捷，且贴近实际生产。

dubbo官方网站：dubbo.io

学习dubbo最佳的方式就是参考官方网站，笔者极力推荐官网，有中文翻译，一键切换，各种详细配置均有提供，还有很多案例供学习参考。

一、dubbo-demo 官方案例详解

dubbo-admin 源码下载地址：https://github.com/apache/dubbo/tree/dubbo-2.5.10

本文采用的版本为2.5.10

可以采用 git clone 或者以直接下载得到一个zip的压缩包，如下:

本次案例主要参考dubbo-demo做详细解答

1、项目结构如下：

dubbo-demo-api ：存放接口

dubbo-demo-provider：具体实现，提供服务方

dubbo-demo-consumer：消费方，主要用于消费

1、dubbo-demo-api

package com.alibaba.dubbo.demo;

public interface DemoService {

    String sayHello(String name);

}

package com.alibaba.dubbo.demo;

public interface UserService {
    
    String getUserName(Long id);

}

2、dubbo-demo-provider

package com.alibaba.dubbo.demo.provider;

import com.alibaba.dubbo.demo.DemoService;
import com.alibaba.dubbo.rpc.RpcContext;

import java.text.SimpleDateFormat;
import java.util.Date;

public class DemoServiceImpl implements DemoService {

    public String sayHello(String name) {
        System.out.println("[" + new SimpleDateFormat("HH:mm:ss").format(new Date()) + "] Hello " + name
                + ", request from consumer: " + RpcContext.getContext().getRemoteAddress());
        return "Hello " + name + ", response form provider: " + RpcContext.getContext().getLocalAddress();
    }

}

package com.alibaba.dubbo.demo.provider;

import java.util.Objects;

import com.alibaba.dubbo.demo.UserService;

public class UserServiceImpl implements UserService {

    @Override
    public String getUserName(Long id) {
        if (Objects.equals(0L, id)) {
            return "张三";
        }
        if (Objects.equals(1L, id)) {
            return "李四";
        }
        return "barnes";
    }

}

package com.alibaba.dubbo.demo.provider;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Provider {

    public static void main(String[] args) throws Exception {
        System.setProperty("java.net.preferIPv4Stack", "true");
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[] { "META-INF/spring/dubbo-demo-provider.xml" });
        context.start();
        System.in.read(); // press any key to exit
    }

}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:dubbo="http://code.alibabatech.com/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-2.5.xsd
       http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd">

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

    <dubbo:registry address="zookeeper://127.0.0.1:2181"/>

    <dubbo:protocol name="dubbo" port="20880"/>

    <bean id="demoService" class="com.alibaba.dubbo.demo.provider.DemoServiceImpl"/>
    <bean id="userService" class="com.alibaba.dubbo.demo.provider.UserServiceImpl"/>

    <dubbo:service interface="com.alibaba.dubbo.demo.DemoService" ref="demoService"/>
    <dubbo:service interface="com.alibaba.dubbo.demo.UserService" ref="userService"/>

</beans>

3、dubbo-demo-consumer

package com.alibaba.dubbo.demo.consumer;

import com.alibaba.dubbo.demo.DemoService;
import com.alibaba.dubbo.demo.UserService;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Consumer {

    public static void main(String[] args) {
        System.setProperty("java.net.preferIPv4Stack", "true");
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new String[] { "META-INF/spring/dubbo-demo-consumer.xml" });
        context.start();
        DemoService demoService = (DemoService) context.getBean("demoService"); // get remote service proxy
        UserService userService = (UserService) context.getBean("userService"); // get remote service proxy

        while (true) {
            try {
                Thread.sleep(2000);
                String hello = demoService.sayHello("world"); // call remote method
                System.out.println(hello); // get result
                
                String userName = userService.getUserName(1L);
                System.out.println("print out for: "+userName);
            } catch (Throwable throwable) {
                throwable.printStackTrace();
            }

        }

    }
}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:dubbo="http://code.alibabatech.com/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-2.5.xsd
       http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd">

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

    <dubbo:registry address="zookeeper://127.0.0.1:2181"/>
    
    <dubbo:reference id="demoService" check="false" interface="com.alibaba.dubbo.demo.DemoService" />
    <dubbo:reference id="userService" check="false" interface="com.alibaba.dubbo.demo.UserService" />

</beans>

provider 和 consumer一些公用配置如下

dubbo.properties

dubbo.application.qos.port=33333

log4j.properties

###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

以上为项目基本代码，编写完成后开始启动项目

1、启动 zookeeper 默认配置端口 2181

2、启动生产者：Provider.java

3、启动消费者：Consumer.java

观看控制台有一下内容打印出，则说明服务正常运行：

二、dubbo-admin 平台搭建及介绍

关于dubbo-admin 平台，笔者也是入踩了好多坑，这里可以简单分享一下

dubbo-admin官方文档：http://dubbo.apache.org/zh-cn/docs/admin/introduction.html

当然安装官方给的构建、启动dubbo-admin的方式也是可以的，但是获取的是最新的dubbo-admin平台

官方给出如下操作：

git clone https://github.com/apache/dubbo-admin.git
cd dubbo-admin
mvn clean package
cd dubbo-admin-distribution/target
java -jar dubbo-admin-0.1.jar

访问 http://localhost:8080
这总方式获取的 dubbo-admin 平台是 spring boot项目，如果需要 war 包的方式获取dubbo-admin 则可以采取以下操作

1、下载对应的源码版本 https://github.com/apache/dubbo/tree/dubbo-2.5.10

2、切记如下操作是一个漫长的等待过程，笔者也曾失败过，不过反复操作，修改配置等重要获得的 war 包

cd dubbo-admin

mvn clean package

进入target 目录小有一个 dubbo-admin-2.5.10.war 文件即是我们所需的war 包，解压，修改文件文件夹名称为 dubbo-admin 放入 tomcat 目录下

3、启动 tomcat 访问 http://127.0.0.1:8080/dubbo-admin/ ，如下：

图为dubbo登录的首页用户名密码默认为 root / root

图为dubbo 中已有注册的2个服务

图为dubbo-admin常用配置，服务启用、禁用，路由，负载均衡等

dubbo-admin 平台构建是一个漫长的过程，需耐心等待

dubbo 官方网站上对应配置，入门案例等等，都做了详细的介绍，实为学习dubbo的最佳平台。

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