一、Dubbo架构

调用关系说明

服务容器负责启动，加载，运行服务提供者。
服务提供者在启动时，向注册中心注册自己提供的服务。
服务消费者在启动时，向注册中心订阅自己所需的服务。
注册中心返回服务提供者地址列表给消费者，如果有变更，注册中心将基于长连接推送变更数据给消费者。
服务消费者，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。
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。

二、代码

代码结构如下

pom文件

<?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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.xiaojie</groupId>
    <artifactId>dubbo-demo</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>dubbo-demo-api</module>
        <module>dubbo-demo-provider</module>
        <module>dubbo-demo-consumer</module>
    </modules>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.2</version>
        <relativePath/>
    </parent>
    <dependencies>
        <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>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.dubbo/dubbo-spring-boot-starter -->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
            <version>2.7.12</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.zookeeper/zookeeper -->
        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
            <version>3.6.2</version>
        </dependency>
        <dependency>
            <groupId>com.101tec</groupId>
            <artifactId>zkclient</artifactId>
            <version>0.10</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.curator/curator-framework -->
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-framework</artifactId>
            <version>4.2.0</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.curator/curator-recipes -->
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-recipes</artifactId>
            <version>4.2.0</version>
        </dependency>
    </dependencies>
</project>

接口类

package com.xiaojie.dubbo.api;

/**
 * @Description:用户接口，只有接口 没有实现类
 * @author: xiaojie
 * @date: 2021.08.02
 */
public interface UserServiceApi {
    /*
     *
     * @param userId
     * @获取用户名称
     * @author xiaojie
     * @date 2021/8/2 9:19
     * @return java.lang.String
     */
    String getUserName(String userId);
}

接口实现类（服务提供者），此模块要依赖dubbo-demo-api模块，或者单独将dubbo-demo-api打成jar包，添加到maven依赖。

package com.xiaojie.dubbo.api.impl;

import com.xiaojie.dubbo.api.UserServiceApi;
import org.apache.dubbo.config.annotation.DubboService;

/**
 * @Description:接口实现类
 * @author: xiaojie
 * @date: 2021.08.02
 */
@DubboService(version = "1.0.0")
public class UserServiceApiImpl implements UserServiceApi {
    @Override
    public String getUserName(String userId) {
        return "我是服务的提供者：我的名字是小杰";
    }
}

application.properties

#spring项目名
spring.application.name=xiaojie-dubbo-provider
#Dubbo provider configuration
dubbo.application.name=dubbo_provider
dubbo.registry.protocol=zookeeper
dubbo.registry.address=192.168.6.136:2181
dubbo.protocol.name=dubbo
dubbo.registry.timeout=50000
#服务端口
dubbo.protocol.port=20881
#扫描注解包通过该设置将服务注册到zookeeper
dubbo.scan.base-packages=com.xiaojie.dubbo.api
server.port=8081

服务消费者

package com.xiaojie.controller;

import com.xiaojie.dubbo.api.UserServiceApi;
import org.apache.dubbo.config.annotation.DubboReference;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @Description:
 * @author: xiaojie
 * @date: 2021.08.02
 */
@RestController
public class ConsumerController {

    @DubboReference(version = "1.0.0")
    private UserServiceApi userServiceApi;

    @GetMapping("/getUserName")
    public  String  getUserName(String userId){
         return userServiceApi.getUserName(userId);
    }
}

application.properties

spring.application.name=xiaojie-dubbo-consumer
dubbo.application.name=dubbo_consumer
dubbo.registry.protocol=zookeeper
#zk地址
dubbo.registry.address=192.168.6.136:2181
dubbo.registry.timeout=50000
server.port=8090