Dubbo——基于注解实现

野性酷女 2021-08-30 21:30 456阅读 0赞

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：  
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