Dubbo——基于注解实现

接口：

public interface EchoService {

    String echo(String message);

}

基于注解的服务端：
通过注解暴露服务，只需要在服务接口上标注@Service注解即可：

import com.alibaba.dubbo.config.annotation.Service;
import com.alibaba.dubbo.rpc.RpcContext;
import com.alibaba.dubbo.samples.echo.api.EchoService;

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

/**
 * @Service是Dubbo的，并不是Spring的。
 * 使用@Service注解后，由Dubbo服务将这个实现提升为Spring容器的Bean，
 * 并且负责配置初始化和服务暴露。
 */
@Service
public class EchoServiceImpl implements EchoService {

    public String echo(String message) {
        String now = new SimpleDateFormat("HH:mm:ss").format(new Date());
        System.out.println("[" + now + "] Hello " + message
                + ", request from consumer: " + RpcContext.getContext().getRemoteAddress());
        return message;
    }
}

使用注解来生成Dubbo的配置信息：

import com.alibaba.dubbo.config.ApplicationConfig;
import com.alibaba.dubbo.config.ProtocolConfig;
import com.alibaba.dubbo.config.ProviderConfig;
import com.alibaba.dubbo.config.RegistryConfig;
import com.alibaba.dubbo.config.spring.context.annotation.EnableDubbo;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

public class AnnotationProvider {
    public static void main(String[] args) throws Exception {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(ProviderConfiguration.class);
        context.start();
        System.in.read();
    }

    @Configuration
    // #1 指定扫描服务的位置
    @EnableDubbo(scanBasePackages = "com.alibaba.dubbo.samples.echo")
    static class ProviderConfiguration {
        @Bean
        public ProviderConfig providerConfig() {
            return new ProviderConfig();
        }

        @Bean
        public ApplicationConfig applicationConfig() {
            ApplicationConfig applicationConfig = new ApplicationConfig();
            applicationConfig.setName("echo-annotation-provider");
            return applicationConfig;
        }

        @Bean
        public RegistryConfig registryConfig() {
            RegistryConfig registryConfig = new RegistryConfig();
            // #2 使用zookeeper作为注册中心，同时给出注册中心ip和端口
            registryConfig.setProtocol("zookeeper");
            registryConfig.setAddress("localhost");
            registryConfig.setPort(2181);
            return registryConfig;
        }

        @Bean
        public ProtocolConfig protocolConfig() {
            ProtocolConfig protocolConfig = new ProtocolConfig();
            // #3 默认服务使用dubbo协议，在20880监听服务
            protocolConfig.setName("dubbo");
            protocolConfig.setPort(20880);
            return protocolConfig;
        }
    }
}

基于注解的客户端：

import com.alibaba.dubbo.config.annotation.Reference;
import com.alibaba.dubbo.samples.echo.api.EchoService;

import org.springframework.stereotype.Component;

/**
 * 通过注解消费服务时，只需要@Reference注解标注，该注解适用于对象字段和方法中。
 */
@Component
public class EchoConsumer {

    @Reference
    private EchoService echoService;

    public String echo(String name) {
        return echoService.echo(name);
    }
}

基于注解的客户端配置：

import com.alibaba.dubbo.config.ApplicationConfig;
import com.alibaba.dubbo.config.ConsumerConfig;
import com.alibaba.dubbo.config.RegistryConfig;
import com.alibaba.dubbo.config.spring.context.annotation.EnableDubbo;
import com.alibaba.dubbo.samples.echo.refer.EchoConsumer;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;


public class AnnotationConsumer {

    public static void main(String[] args) {
        // #1 基于注解配置初始化spring上下文
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(ConsumerConfiguration.class);
        context.start();
        // #2 发起服务调用
        EchoConsumer echoService = context.getBean(EchoConsumer.class);
        String hello = echoService.echo("Hello world!");
        System.out.println("result: " + hello);
    }

    @Configuration
    // #3 指定要扫描的消费注解，会触发注入
    @EnableDubbo(scanBasePackages = "com.alibaba.dubbo.samples.echo")
    @ComponentScan(value = {"com.alibaba.dubbo.samples.echo"})
    static class ConsumerConfiguration {
        @Bean
        public ApplicationConfig applicationConfig() {
            ApplicationConfig applicationConfig = new ApplicationConfig();
            applicationConfig.setName("echo-annotation-consumer");
            return applicationConfig;
        }

        @Bean
        public ConsumerConfig consumerConfig() {
            return new ConsumerConfig();
        }

        @Bean
        public RegistryConfig registryConfig() {
            RegistryConfig registryConfig = new RegistryConfig();
            // #4 使用zookeeper作为注册中心，同时给出注册中心ip和端口
            registryConfig.setProtocol("zookeeper");
            registryConfig.setAddress("localhost");
            registryConfig.setPort(2181);
            return registryConfig;
        }
    }
}

测试：

启动zookeeper，启动服务端和客户端，客户端打印：