Dubbo（26）Dubbo的配置方式有哪些？

Dubbo支持多种配置方式，包括XML配置、注解配置以及基于Spring Boot的配置方式。每种配置方式都有其独特的优势和使用场景。下面详细介绍这三种配置方式，并结合具体代码示例进行说明。

1. XML 配置

XML配置是最传统的配置方式，通过Spring的配置文件来描述Dubbo的各类配置。

示例代码

pom.xml

<dependencies>
    
    <dependency>
        <groupId>org.apache.dubbogroupId>
        <artifactId>dubbo-spring-boot-starterartifactId>
        <version>2.7.8version>
    dependency>

    
    <dependency>
        <groupId>org.apache.curatorgroupId>
        <artifactId>curator-recipesartifactId>
        <version>4.2.0version>
    dependency>

    
    <dependency>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starterartifactId>
    dependency>
dependencies>

dubbo-provider.xml

<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">

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

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

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

    
    <dubbo:service interface="com.example.DemoService" ref="demoServiceImpl"/>
    
    <bean id="demoServiceImpl" class="com.example.DemoServiceImpl"/>
beans>

dubbo-consumer.xml

<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">

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

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

    
    <dubbo:reference id="demoService" interface="com.example.DemoService"/>
beans>

服务接口和实现

package com.example;

public interface DemoService {
    String sayHello(String name);
}

package com.example;

public class DemoServiceImpl implements DemoService {
    @Override
    public String sayHello(String name) {
        return "Hello, " + name;
    }
}

消费者

package com.example;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Consumer {
    public static void main(String[] args) {
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("dubbo-consumer.xml");
        context.start();
        DemoService demoService = (DemoService) context.getBean("demoService");
        String hello = demoService.sayHello("World");
        System.out.println(hello);
    }
}

2. 注解配置

注解配置方式简化了XML配置，通过注解直接在代码中进行配置。

示例代码

pom.xml

与XML配置相同。

application.yml

dubbo:
  application:
    name: dubbo-demo-provider
  registry:
    address: zookeeper://127.0.0.1:2181
  protocol:
    name: dubbo
    port: 20880
  scan:
    base-packages: com.example

服务接口和实现

package com.example;

public interface DemoService {
    String sayHello(String name);
}

package com.example;

import org.apache.dubbo.config.annotation.DubboService;
import org.springframework.stereotype.Component;

@DubboService
@Component
public class DemoServiceImpl implements DemoService {
    @Override
    public String sayHello(String name) {
        return "Hello, " + name;
    }
}

消费者

package com.example;

import org.apache.dubbo.config.annotation.DubboReference;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class DubboConsumerApplication {
    public static void main(String[] args) {
        SpringApplication.run(DubboConsumerApplication.class, args);
    }

    @DubboReference
    private DemoService demoService;

    @Bean
    public CommandLineRunner demo() {
        return args -> {
            String result = demoService.sayHello("World");
            System.out.println(result);
        };
    }
}

3. 基于Spring Boot的配置

基于Spring Boot的配置方式是目前最为流行的配置方式，结合了Spring Boot的自动配置特性，简化了配置过程。

示例代码

pom.xml

与XML配置相同。

application.yml

server:
  port: 8081

dubbo:
  application:
    name: dubbo-demo-provider
  registry:
    address: zookeeper://127.0.0.1:2181
  protocol:
    name: dubbo
    port: 20880
  scan:
    base-packages: com.example

服务接口和实现

package com.example;

public interface DemoService {
    String sayHello(String name);
}

package com.example;

import org.apache.dubbo.config.annotation.DubboService;

@DubboService
public class DemoServiceImpl implements DemoService {
    @Override
    public String sayHello(String name) {
        return "Hello, " + name;
    }
}

消费者

package com.example;

import org.apache.dubbo.config.annotation.DubboReference;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class DubboConsumerApplication {
    public static void main(String[] args) {
        SpringApplication.run(DubboConsumerApplication.class, args);
    }

    @DubboReference
    private DemoService demoService;

    @Bean
    public CommandLineRunner demo() {
        return args -> {
            String result = demoService.sayHello("World");
            System.out.println(result);
        };
    }
}

总结

通过上述示例，我们可以看到Dubbo支持以下三种主要配置方式：

1. XML 配置：传统的配置方式，通过Spring的配置文件来描述Dubbo的各类配置。
2. 注解配置：通过注解直接在代码中进行配置，简化了XML配置。
3. 基于Spring Boot的配置：结合Spring Boot的自动配置特性，进一步简化了配置过程。

每种配置方式都有其独特的优势和适用场景，可以根据项目需求选择合适的配置方式。