Dubbo2.7.3入门

2.7.X的Dubbo，包名不再是com.alibaba，而是org.apache

先看工程目录结构

一个公共api模块，一个SpringBoot项目充当Dubbo服务，一个SpringBoot项目充当服务消费者。

代码

父项目pom

<?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>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <modelVersion>4.0.0</modelVersion>

    <groupId>com.demo</groupId>
    <artifactId>dubbo-2.7.3</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>dubbo-api</module>
        <module>dubbo-service</module>
        <module>dubbo-consumer</module>
    </modules>

    <properties>
        <java.version>1.8</java.version>
        <dubbo.version>2.7.3</dubbo.version>
        <!--如果curator版本与zookeeper不对应，会报错：KeeperErrorCode = Unimplemented for /dubbo/com.demo.common.HelloService-->
        <curator.version>2.13.0</curator.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo</artifactId>
            <version>${dubbo.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
            <version>${dubbo.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-framework</artifactId>
            <version>${curator.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-recipes</artifactId>
            <version>${curator.version}</version>
        </dependency>
        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>

</project>

　　

api模块

只是提供了一个公共的服务接口

package com.demo.common;

public interface HelloService {
    String hello();
}

pom

<?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-2.7.3</artifactId>
        <groupId>com.demo</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>dubbo-api</artifactId>
</project>

　　

Dubbo服务模块

主要提供服务实现

package com.demo.dubboservice.service.impl;

import com.demo.common.HelloService;
import org.apache.dubbo.config.annotation.Service;

/**
 *  建议由服务提供方设置超时,在 Provider 上尽量多配置 Consumer 端属性
 *  timeout 方法调用超时
 *  retries 失败重试次数，缺省是 2 [2]
 *  loadbalance 负载均衡算法 [3]，缺省是随机 random。还可以有轮询 roundrobin、最不活跃优先 [4] leastactive 等
 *  actives 消费者端，最大并发调用限制，即当 Consumer 对一个服务的并发调用到上限后，新调用会阻塞直到超时
 */
@Service(registry = "dubboRegistry", timeout = 3000, version = "1.0", retries = 3, loadbalance = "random", actives = 5)
public class HelloServiceImpl implements HelloService {
    @Override
    public String hello() {
        return "动物园里有大西几! 小凶许! 小脑斧! 梅发怒!";
    }
}

application.properties

spring.application.name=service-provider
server.port=9999
spring.main.allow-bean-definition-overriding=true

# Dubbo Application
# The default value of dubbo.application.name is ${spring.application.name}
# dubbo.application.name=${spring.application.name}

# 扫描dubbo服务(@Service.. @Reference..)
dubbo.scan.basePackages=com.demo.dubboservice.service.impl

# 通信协议
dubbo.protocol.id = dubbo
dubbo.protocol.name = dubbo
dubbo.protocol.port = 20880

# 注册中心
dubbo.registry.id = dubboRegistry
dubbo.registry.timeout=5000
dubbo.registry.address=zookeeper://127.0.0.1:2181
# Dubbo 支持 zkclient 和 curator 两种 Zookeeper 客户端实现：在2.7.x的版本中已经移除了zkclient的实现,如果要使用zkclient客户端,需要自行拓展
dubbo.registry.client=curator
# 元数据地址
dubbo.metadata-report.address=zookeeper://127.0.0.1:2181

　　

pom

<?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-2.7.3</artifactId>
		<groupId>com.demo</groupId>
		<version>1.0-SNAPSHOT</version>
	</parent>

	<modelVersion>4.0.0</modelVersion>

	<artifactId>dubbo-service</artifactId>
	<name>dubbo-service</name>
	<description>Demo project for Spring Boot</description>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>com.demo</groupId>
            <artifactId>dubbo-api</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>

　　

服务消费者模块

调用dubbo服务，提供前端接口

package com.demo.dubboconsumer.controller;

import com.demo.common.HelloService;
import org.apache.dubbo.config.annotation.Reference;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {
    @Reference(version = "1.0")
    private HelloService helloService;

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

application.properties

spring.application.name=dubbo-consumer
server.port=9990
spring.main.allow-bean-definition-overriding=true

# Dubbo Application
# The default value of dubbo.application.name is ${spring.application.name}
# dubbo.application.name=${spring.application.name}

# 扫描dubbo服务(@Service.. @Reference..)
dubbo.scan.basePackages=com.demo.dubboconsumer.controller

# 通信协议
dubbo.protocol.id=dubbo
dubbo.protocol.name=dubbo
dubbo.protocol.port=20880

# 注册中心
dubbo.registry.id=dubboRegistry
dubbo.registry.timeout=5000
dubbo.registry.address=zookeeper://127.0.0.1:2181
dubbo.registry.client=curator
# 元数据地址
dubbo.metadata-report.address=zookeeper://127.0.0.1:2181

　　

pom

<?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-2.7.3</artifactId>
		<groupId>com.demo</groupId>
		<version>1.0-SNAPSHOT</version>
	</parent>

	<modelVersion>4.0.0</modelVersion>

	<artifactId>dubbo-consumer</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>dubbo-consumer</name>
	<description>Demo project for Spring Boot</description>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

        <dependency>
            <groupId>com.demo</groupId>
            <artifactId>dubbo-api</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>

　　

代码搞定，又出了个新问题

为什么呢，因为中央仓库里还没有2.7.3版本的依赖，等有了就不会出现这个问题了（这里就要吐槽一下，Dubbo-SpringBoot-Starter项目与Dubbo项目的版本不同步有点尴尬）

临时解决，去GitHub上下载2.7.3的源码，然后本地install。

解压缩，然后进入根目录，执行 mvn install -Dmaven.test.skip=true

启动

先在本地启动一个3.4.X的zookeeper（去官网下载，然后复制conf里的zoo_sample.cfg，重命名zoo.cfg，即可启动），然后先后启动Dubbo服务以及消费者项目

访问

如果你启动Dubbo管控台（注：最好是最新版），可以看见Dubbo服务

访问 http://localhost:8080/#/

点击查看【详情】，在最后有个【元数据】信息，这与前面配置的【元数据地址】是相关联的。

源码地址：https://github.com/Mysakura/dubbo-2.7.3-demo