1. Dubbo – 分布式系统的相关概念（大型互联网项目架构目标 集群和分布式 架构演进）、Dubbo概述（Dubbo的概念和架构）、Dubbo快速入门（Zookepper的安装：注册中心中心）

2. Dubbo – Dubbo快速入门代码编写

3.Dubbo – dubbo-admin 的安装 介绍 使用

4. Dubbo – dubbo高级特性（序列化 地址缓存 超时与重试机制 多版本：灰度发布 负载均衡 集群容错策略 服务降级）

做这个案例需要安装Zookeeper（注册中心）

1. Dubbo快速入门代码编写

1.1 需求分析

1.2 项目和模块创建

创建一个dubbo-pro项目和他的2个模块，其中dubbo-service是普通模块，dubbo-web是web工程模块。

1.3 导入相关依赖

<?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">
    <parent>
        <artifactId>dubbo-pro</artifactId>
        <groupId>com.tian</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <packaging>war</packaging>

    <artifactId>dubbo-web</artifactId>

    <properties>
        <spring.version>5.1.9.RELEASE</spring.version>
        <dubbo.version>2.7.4.1</dubbo.version>
        <zookeeper.version>4.0.0</zookeeper.version>
    </properties>

    <dependencies>
        <!-- servlet3.0规范的坐标 -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>
        <!--spring的坐标-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--springmvc的坐标-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!--日志-->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.21</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.21</version>
        </dependency>


        <!--Dubbo的起步依赖，版本2.7之后统一为rg.apache.dubb -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo</artifactId>
            <version>${dubbo.version}</version>
        </dependency>
        <!--ZooKeeper客户端实现 -->
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-framework</artifactId>
            <version>${zookeeper.version}</version>
        </dependency>
        <!--ZooKeeper客户端实现 -->
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-recipes</artifactId>
            <version>${zookeeper.version}</version>
        </dependency>


        <!--公共接口模块-->
        <dependency>
            <groupId>com.tian</groupId>
            <artifactId>dubbo-service</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>

    </dependencies>
</project>

<?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">
    <parent>
        <artifactId>dubbo-pro</artifactId>
        <groupId>com.tian</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>dubbo-service</artifactId>

    <properties>
        <spring.version>5.1.9.RELEASE</spring.version>
        <dubbo.version>2.7.4.1</dubbo.version>
        <zookeeper.version>4.0.0</zookeeper.version>
    </properties>

    <dependencies>
        <!-- servlet3.0规范的坐标 -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>
        <!--spring的坐标-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--springmvc的坐标-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!--日志-->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.21</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.21</version>
        </dependency>


        <!--Dubbo的起步依赖，版本2.7之后统一为rg.apache.dubb -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo</artifactId>
            <version>${dubbo.version}</version>
        </dependency>
        <!--ZooKeeper客户端实现 -->
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-framework</artifactId>
            <version>${zookeeper.version}</version>
        </dependency>
        <!--ZooKeeper客户端实现 -->
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-recipes</artifactId>
            <version>${zookeeper.version}</version>
        </dependency>
    </dependencies>


</project>

1.4 编写提供服务的接口

DubboService.java

package com.tian.service;

public interface DubboService {

    public String helloDubbo();
}

DubboServiceImpl.java

package com.tian.service.impl;

import com.tian.service.DubboService;
import org.springframework.stereotype.Service;

@Service
public class DubboServiceImpl implements DubboService {
    @Override
    public String helloDubbo() {
        return "Hello Dubbo";
    }
}

配置日志文件和包扫描：

applicationContext.xml

<?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:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
          http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
    <context:component-scan base-package="com.tian.service"/>
</beans>

log4j.properties

# DEBUG < INFO < WARN < ERROR < FATAL
# Global logging configuration
log4j.rootLogger=info, stdout,file
# My logging configuration...
#log4j.logger.com.tocersoft.school=DEBUG
#log4j.logger.net.sf.hibernate.cache=debug
## Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p %d %C: %m%n

log4j.appender.file=org.apache.log4j.FileAppender
log4j.appender.file.File=../logs/iask.log
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss}  %l  %m%n

1.5 编写调用服务的程序

DubboController.java

package com.tian.controller;

import com.tian.service.DubboService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/dubbo")
public class DubboController {

    @Autowired
    private DubboService dubboService;

    @RequestMapping("/hello")
    public String helloDubbo() {
        return dubboService.helloDubbo();
    }
}

springmvc.xml

<?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:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
    <mvc:annotation-driven/>
    <context:component-scan base-package="com.tian.controller"/>
</beans>

log4j.properties

# DEBUG < INFO < WARN < ERROR < FATAL
# Global logging configuration
log4j.rootLogger=info, stdout,file
# My logging configuration...
#log4j.logger.com.tocersoft.school=DEBUG
#log4j.logger.net.sf.hibernate.cache=debug
## Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p %d %C: %m%n

log4j.appender.file=org.apache.log4j.FileAppender
log4j.appender.file.File=../logs/iask.log
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss}  %l  %m%n

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <!-- spring -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath*:spring/applicationContext.xml</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <!-- Springmvc -->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!-- 指定加载的配置文件 ，通过参数contextConfigLocation加载-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring/springmvc.xml</param-value>
        </init-param>
    </servlet>

    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>*.do</url-pattern>
    </servlet-mapping>
</web-app>

1.6 安装dubbo-service（被依赖的模块需要安装）

说明：我安装了一个Maven Helper的

1.7 配置Tomcat

1.8 启动测试

http://localhost:8080/dubbo/hello.do

1.9 说明

现在的架构：虽然现在模块拆分了，但是并不是微服务架构，因为service模块（jar包）不可以作为独立的模块提供服务。

我们还需要把他改装成为这种结构

1.10 改造dubbo-service：服务提供者

1）把dubbo-service的打包方式改为war

2）改造 DubboServiceImpl

package com.tian.service.impl;

import com.tian.service.DubboService;
import org.apache.dubbo.config.annotation.Service;

/**
 * 现在不需要 @Service 注解了, @Service注解的作用是把该类的对象创建出来, 放到IOC中
 */


/*
   注意现在的包是org.apache.dubbo和上面是不同的, 这个注解的作用是将这个类提供的方法（服务）
   对外发布. 将访问的地址（ip + 端口号 + 路径） 注册到注册中心
 */
@Service
public class DubboServiceImpl implements DubboService {
    @Override
    public String helloDubbo() {
        return "Hello Dubbo";
    }
}

3）配置注册中心地址

<?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://dubbo.apache.org/schema/dubbo"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://dubbo.apache.org/schema/dubbo http://dubbo.apache.org/schema/dubbo/dubbo.xsd">

    <!--    <context:component-scan base-package="com.tian.service"/>-->

    <!--    配置项目的名称 唯一-->
    <dubbo:application name="dubbo-service"/>
    <!--    配置注册中心的地址-->
    <dubbo:registry address="zookeeper://192.168.135.130:2181"/>
    <!--    配置dubbo包扫描-->
    <dubbo:annotation package="com.tian.service.impl"/>
</beans>

4）把dubbo-service改造成web项目

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <!-- spring -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath*:spring/applicationContext.xml</param-value>
    </context-param>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
</web-app>
    <!--    去掉springMVC相关配置-->

5）配置Tomcat 启动服务

我把这个端口设置成为了9000

如果启动没有报错就证明改造成功了。

1.11 改造dubbo-web：服务消费者

1）建立一个模块，里面存放公告的接口，然后安装该模块

2）dubbo-service和dubbo-web引入该模块

然后删去dubbo-web引入dubbo-service的依赖：

3）配置注册中心

<?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:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:dubbo="http://dubbo.apache.org/schema/dubbo"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd http://dubbo.apache.org/schema/dubbo http://dubbo.apache.org/schema/dubbo/dubbo.xsd">
    <mvc:annotation-driven/>
    <context:component-scan base-package="com.tian.controller"/>

    <!--    配置项目的名称 唯一-->
    <dubbo:application name="dubbo-web">
        <dubbo:parameter key="qos.port" value="33333"/>
    </dubbo:application>
    <!--    配置注册中心的地址-->
    <dubbo:registry address="zookeeper://192.168.135.130:2181"/>
    <!--    配置dubbo包扫描-->
    <dubbo:annotation package="com.tian.controller"/>
</beans>

4）改造web.xml

删去了spring相关的配置，留下了SpringMVC相关配置。

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <!-- Springmvc -->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!-- 指定加载的配置文件 ，通过参数contextConfigLocation加载-->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring/springmvc.xml</param-value>
        </init-param>
    </servlet>

    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>*.do</url-pattern>
    </servlet-mapping>
</web-app>

5）完成对DubboController的改造

DubboController.java

package com.tian.controller;

import com.tian.service.DubboService;
import org.apache.dubbo.config.annotation.Reference;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/dubbo")
public class DubboController {

//    @Autowired 本地注入

    /**
     * 1. 从zookeeper注册中心获取userService的访问路径
     * 2. 进行远程调用（RPC）
     * 3. 将结果封装称为一个代理对象, 给变量赋值
     */
    @Reference// 远程注入 org.apache.dubbo.config.annotation.Reference
    private DubboService dubboService;

    @RequestMapping("/hello")
    public String helloDubbo() {
        return dubboService.helloDubbo();
    }
}

1.12访问测试：需要重启2个Tomcat服务器（dubbo-web和dubbo-service）

http://localhost:8080/dubbo/hello.do

2. 说明：源码下载

这是我做完的源码，如有需要，可以下载：

链接：https://pan.baidu.com/s/1bx38PRRaNy2DJ84-jRFTAA?pwd=3210 
提取码：3210