开发dubbo应用程序(一)入门demo详解

1.简介:

引用自Dubbo官方文档简介:

http://dubbo.apache.org/zh-cn/docs/user/dependencies.html

随着互联网的发展，网站应用的规模不断扩大，常规的垂直应用架构已无法应对，分布式服务架构以及流动计算架构势在必行，亟需一个治理系统确保架构有条不紊的演进。

单一应用架构

当网站流量很小时，只需一个应用，将所有功能都部署在一起，以减少部署节点和成本。此时，用于简化增删改查工作量的数据访问框架(ORM)是关键。

垂直应用架构

当访问量逐渐增大，单一应用增加机器带来的加速度越来越小，将应用拆成互不相干的几个应用，以提升效率。此时，用于加速前端页面开发的Web框架(MVC)是关键。

分布式服务架构

当垂直应用越来越多，应用之间交互不可避免，将核心业务抽取出来，作为独立的服务，逐渐形成稳定的服务中心，使前端应用能更快速的响应多变的市场需求。此时，用于提高业务复用及整合的分布式服务框架(RPC)是关键。

流动计算架构

当服务越来越多，容量的评估，小服务资源的浪费等问题逐渐显现，此时需增加一个调度中心基于访问压力实时管理集群容量，提高集群利用率。此时，用于提高机器利用率的资源调度和治理中心(SOA)是关键。

2.Dubbo相关实例

dubbo的官方sample的github地址:

https://github.com/apache/dubbo-samples/tree/2.6.x

以下的demo参考以上官方文档而来：

pom.xm

<?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.home</groupId>
  <artifactId>dubbo-demo</artifactId>
  <version>1.0-SNAPSHOT</version>
  <modules>
    <module>demo-api</module>
  </modules>
  <packaging>pom</packaging>

  <name>dubbo-demo Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
    <dubbo.version>2.7.3</dubbo.version>
  </properties>

  <dependencies>
    <!-- 导入Dubbo jar包 -->
    <dependency>
      <groupId>org.apache.dubbo</groupId>
      <artifactId>dubbo</artifactId>
      <version>${dubbo.version}</version>
      <exclusions>
        <exclusion>
          <artifactId>spring</artifactId>
          <groupId>org.springframework</groupId>
        </exclusion>
      </exclusions>
    </dependency>

    <dependency>
      <groupId>org.apache.curator</groupId>
      <artifactId>curator-framework</artifactId>
      <version>4.0.1</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>
    <!-- spring MVC -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>4.3.14.RELEASE</version>
    </dependency>

    <!-- 访问zookeeper 的zkClient包 -->
    <dependency>
      <groupId>com.101tec</groupId>
      <artifactId>zkclient</artifactId>
      <version>0.11</version>
    </dependency>

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
  </dependencies>

  <build>
    <finalName>dubbo-demo</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

EchoProvider:

package com.dubbo.service.provider;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.io.IOException;

public class EchoProvider {

    public static void main(String[] args) throws IOException {

        ClassPathXmlApplicationContext context =  new ClassPathXmlApplicationContext(
                new String[]{"spring/echo-provider.xml"}
        );
        context.start();
        System.in.read();

    }
}

EchoServiceImpl:

package com.dubbo.service.impl;

import com.alibaba.dubbo.rpc.RpcContext;
import com.dubbo.service.EchoService;

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

public class EchoServiceImpl implements EchoService {

    @Override
    public String echo(String name) {
        System.out.println("[" + new SimpleDateFormat("HH:mm:ss").format(new Date()) + "] Hello " +
                name + ", request from consumer: " + RpcContext.getContext().getRemoteAddress());
        return "Hello " + name + ", response from provider: " + RpcContext.getContext().getLocalAddress();
    }
}

echo-provider.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:dubbo="http://dubbo.apache.org/schema/dubbo"
       xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"
       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 http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    <context:property-placeholder/>

    <!--服务提供方应用名称,方便用于依赖追踪-->
    <dubbo:application name="echo-provide"/>
    <!--使用本地zookeeper作为注册中心-->
    <dubbo:registry address="zookeeper://127.0.0.1:2181"/>
    <!--只用dubbo的协议并制定监听20880的端口-->
    <dubbo:protocol name="dubbo" port="20880"/>
    <!--通过xml方式吧实现配置为demoService,让spring托管和实例化-->
    <bean id="echoService" class="com.dubbo.service.impl.EchoServiceImpl"/>
    <!--声明要暴露的接口-->
    <dubbo:service interface="com.dubbo.service.EchoService" ref="echoService"/>
</beans>

EchoProvider:

package com.dubbo.service.provider;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import java.io.IOException;

public class EchoProvider {

    public static void main(String[] args) throws IOException {

        ClassPathXmlApplicationContext context =  new ClassPathXmlApplicationContext(
                new String[]{"spring/echo-provider.xml"}
        );
        context.start();
        System.in.read();

    }
}

echo-consumer.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:dubbo="http://dubbo.apache.org/schema/dubbo"
       xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context"
       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 http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    <context:property-placeholder/>

    <!--服务方应用名称-->
    <dubbo:application name="echo-consumer"/>

    <!--使用本地zookeeper作为注册中心-->
    <dubbo:registry address="zookeeper://127.0.0.1:2181"/>

    <!--指定要消费的服务-->
    <dubbo:reference id="echoService" check="false" interface="com.dubbo.service.EchoService"/>

</beans>

EchoConsumer

package com.dubbo.service.consumer;

import com.dubbo.service.EchoService;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class EchoConsumer {

    public static void main(String[] args) {

        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(
                new String[]{"spring/echo-consumer.xml"}
        );
        context.start();
        EchoService echoService = (EchoService) context.getBean("echoService");

        String status = echoService.echo("hello world");

        System.out.println("echo:"+status);

    }
}

主要需要先启动Zokeeper,然后启动提供方,之后启动消费方就可以收到相应的消息了.

3.使用注解形式,摘自官方文档

项目结构如下:

AnnotationAction

/*
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements.  See the NOTICE file distributed with
 *   this work for additional information regarding copyright ownership.
 *   The ASF licenses this file to You under the Apache License, Version 2.0
 *   (the "License"); you may not use this file except in compliance with
 *   the License.  You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 *
 */

package annotation.action;

import annotation.AnnotationConstants;
import annotation.api.GreetingService;
import annotation.api.HelloService;
import org.apache.dubbo.config.annotation.Method;
import org.apache.dubbo.config.annotation.Reference;
import org.springframework.stereotype.Component;

@Component("annotationAction")
public class AnnotationAction {

    @Reference(interfaceClass = HelloService.class, version = AnnotationConstants.VERSION)
    private HelloService helloService;

    @Reference(interfaceClass = GreetingService.class,
            version = AnnotationConstants.VERSION,
            methods = {@Method(name = "greeting", timeout = 250, retries = 1)})
    private GreetingService greetingService;

    public String doSayHello(String name) {
        try {
            return helloService.sayHello(name);
        } catch (Exception e) {
            e.printStackTrace();
            return "Throw Exception";
        }
    }

    public String doSayGoodbye(String name) {
        try {
            return helloService.sayGoodbye(name);
        } catch (Exception e) {
            e.printStackTrace();
            return "Throw Exception";
        }

    }

    public String doGreeting(String name) {
        try {
            return greetingService.greeting(name);
        } catch (Exception e) {
            e.printStackTrace();
            return "Throw Exception";
        }

    }

    public String replyGreeting(String name) {
        try {
            return greetingService.replyGreeting(name);
        } catch (Exception e) {
            e.printStackTrace();
            return "Throw Exception";
        }
    }
}

GreetingService

package annotation.api;

import java.util.concurrent.CompletableFuture;

public interface GreetingService {

    String greeting(String name);

    default String replyGreeting(String name) {
        return "Fine, " + name;
    }

    default CompletableFuture<String> greeting(String name, byte signal) {
        return CompletableFuture.completedFuture(greeting(name));
    }

}

HelloService

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package annotation.api;

public interface HelloService {

    String sayHello(String name);

    default String sayGoodbye(String name) {
        return "Goodbye, " + name;
    }
}

AnnotationGreetingServiceImpl

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package annotation.impl;

import annotation.AnnotationConstants;
import annotation.api.GreetingService;
import org.apache.dubbo.config.annotation.Service;

@Service(version = AnnotationConstants.VERSION)
public class AnnotationGreetingServiceImpl implements GreetingService {

    @Override
    public String greeting(String name) {
        System.out.println("provider received invoke of greeting: " + name);
        sleepWhile();
        return "Annotation, greeting " + name;
    }

    public String replyGreeting(String name) {
        System.out.println("provider received invoke of replyGreeting: " + name);
        sleepWhile();
        return "Annotation, fine " + name;
    }

    private void sleepWhile() {
        try {
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

AnnotationHelloServiceImpl

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package annotation.impl;

import annotation.AnnotationConstants;
import annotation.api.HelloService;
import org.apache.dubbo.config.annotation.Method;
import org.apache.dubbo.config.annotation.Service;

@Service(version = AnnotationConstants.VERSION, methods = {@Method(name = "sayGoodbye", timeout = 250, retries = 0)})
public class AnnotationHelloServiceImpl implements HelloService {

    @Override
    public String sayHello(String name) {
        System.out.println("provider received invoke of sayHello: " + name);
        sleepWhile();
        return "Annotation, hello " + name;
    }

    public String sayGoodbye(String name) {
        System.out.println("provider received invoke of sayGoodbye: " + name);
        sleepWhile();
        return "Goodbye, " + name;
    }

    private void sleepWhile() {
        try {
            Thread.sleep(300);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

}

AnnotationConstants

package annotation;

public interface AnnotationConstants {
    String VERSION = "1.0.0_annotation";
}

AnnotationConsumerBootstrap

/*
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements.  See the NOTICE file distributed with
 *   this work for additional information regarding copyright ownership.
 *   The ASF licenses this file to You under the Apache License, Version 2.0
 *   (the "License"); you may not use this file except in compliance with
 *   the License.  You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 *
 */

package annotation;

import annotation.action.AnnotationAction;
import org.apache.dubbo.config.spring.context.annotation.EnableDubbo;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;

public class AnnotationConsumerBootstrap {

    public static void main(String[] args) {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(ConsumerConfiguration.class);
        context.start();
        final AnnotationAction annotationAction = (AnnotationAction) context.getBean("annotationAction");

        System.out.println("hello :" + annotationAction.doSayHello("world"));
        System.out.println("goodbye :" + annotationAction.doSayGoodbye("world"));
        System.out.println("greeting :" + annotationAction.doGreeting("world"));
        System.out.println("reply :" + annotationAction.replyGreeting("world"));
    }

    @Configuration
    @EnableDubbo(scanBasePackages = "annotation.action")
    @PropertySource("classpath:/spring/dubbo-consumer.properties")
    @ComponentScan(value = {"annotation.action"})
    static public class ConsumerConfiguration {

    }

}

AnnotationProviderBootstrap

/*
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements.  See the NOTICE file distributed with
 *   this work for additional information regarding copyright ownership.
 *   The ASF licenses this file to You under the Apache License, Version 2.0
 *   (the "License"); you may not use this file except in compliance with
 *   the License.  You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 *
 */

package annotation;

import org.apache.dubbo.config.ProviderConfig;
import org.apache.dubbo.config.spring.context.annotation.EnableDubbo;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;

import java.util.concurrent.CountDownLatch;

public class AnnotationProviderBootstrap {

    public static void main(String[] args) throws Exception {
        new EmbeddedZooKeeper(2181, false).start();

        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(ProviderConfiguration.class);
        context.start();

        System.out.println("dubbo service started.");
        new CountDownLatch(1).await();
    }

    @Configuration
    @EnableDubbo(scanBasePackages = "annotation.impl")
    @PropertySource("classpath:/spring/dubbo-provider.properties")
    static public class ProviderConfiguration {
        @Bean
        public ProviderConfig providerConfig() {
            ProviderConfig providerConfig = new ProviderConfig();
            providerConfig.setTimeout(1000);
            return providerConfig;
        }
    }

}

EmbeddedZooKeeper:

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package annotation;

import org.apache.zookeeper.server.ServerConfig;
import org.apache.zookeeper.server.ZooKeeperServerMain;
import org.apache.zookeeper.server.quorum.QuorumPeerConfig;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.SmartLifecycle;
import org.springframework.util.ErrorHandler;
import org.springframework.util.SocketUtils;

import java.io.File;
import java.lang.reflect.Method;
import java.util.Properties;
import java.util.UUID;

/**
 * from: https://github.com/spring-projects/spring-xd/blob/v1.3.1.RELEASE/spring-xd-dirt/src/main/java/org/springframework/xd/dirt/zookeeper/ZooKeeperUtils.java
 * <p>
 * Helper class to start an embedded instance of standalone (non clustered) ZooKeeper.
 * <p>
 * NOTE: at least an external standalone server (if not an ensemble) are recommended, even for
 * {@link org.springframework.xd.dirt.server.singlenode.SingleNodeApplication}
 *
 * @author Patrick Peralta
 * @author Mark Fisher
 * @author David Turanski
 */
public class EmbeddedZooKeeper implements SmartLifecycle {

    /**
     * Logger.
     */
    private static final Logger logger = LoggerFactory.getLogger(EmbeddedZooKeeper.class);

    /**
     * ZooKeeper client port. This will be determined dynamically upon startup.
     */
    private final int clientPort;

    /**
     * Whether to auto-start. Default is true.
     */
    private boolean autoStartup = true;

    /**
     * Lifecycle phase. Default is 0.
     */
    private int phase = 0;

    /**
     * Thread for running the ZooKeeper server.
     */
    private volatile Thread zkServerThread;

    /**
     * ZooKeeper server.
     */
    private volatile ZooKeeperServerMain zkServer;

    /**
     * {@link ErrorHandler} to be invoked if an Exception is thrown from the ZooKeeper server thread.
     */
    private ErrorHandler errorHandler;

    private boolean daemon = true;

    /**
     * Construct an EmbeddedZooKeeper with a random port.
     */
    public EmbeddedZooKeeper() {
        clientPort = SocketUtils.findAvailableTcpPort();
    }

    /**
     * Construct an EmbeddedZooKeeper with the provided port.
     *
     * @param clientPort port for ZooKeeper server to bind to
     */
    public EmbeddedZooKeeper(int clientPort, boolean daemon) {
        this.clientPort = clientPort;
        this.daemon = daemon;
    }

    /**
     * Returns the port that clients should use to connect to this embedded server.
     *
     * @return dynamically determined client port
     */
    public int getClientPort() {
        return this.clientPort;
    }

    /**
     * Specify whether to start automatically. Default is true.
     *
     * @param autoStartup whether to start automatically
     */
    public void setAutoStartup(boolean autoStartup) {
        this.autoStartup = autoStartup;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean isAutoStartup() {
        return this.autoStartup;
    }

    /**
     * Specify the lifecycle phase for the embedded server.
     *
     * @param phase the lifecycle phase
     */
    public void setPhase(int phase) {
        this.phase = phase;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public int getPhase() {
        return this.phase;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean isRunning() {
        return (zkServerThread != null);
    }

    /**
     * Start the ZooKeeper server in a background thread.
     * <p>
     * Register an error handler via {@link #setErrorHandler} in order to handle
     * any exceptions thrown during startup or execution.
     */
    @Override
    public synchronized void start() {
        if (zkServerThread == null) {
            zkServerThread = new Thread(new ServerRunnable(), "ZooKeeper Server Starter");
            zkServerThread.setDaemon(daemon);
            zkServerThread.start();
        }
    }

    /**
     * Shutdown the ZooKeeper server.
     */
    @Override
    public synchronized void stop() {
        if (zkServerThread != null) {
            // The shutdown method is protected...thus this hack to invoke it.
            // This will log an exception on shutdown; see
            // https://issues.apache.org/jira/browse/ZOOKEEPER-1873 for details.
            try {
                Method shutdown = ZooKeeperServerMain.class.getDeclaredMethod("shutdown");
                shutdown.setAccessible(true);
                shutdown.invoke(zkServer);
            } catch (Exception e) {
                throw new RuntimeException(e);
            }

            // It is expected that the thread will exit after
            // the server is shutdown; this will block until
            // the shutdown is complete.
            try {
                zkServerThread.join(5000);
                zkServerThread = null;
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
                logger.warn("Interrupted while waiting for embedded ZooKeeper to exit");
                // abandoning zk thread
                zkServerThread = null;
            }
        }
    }

    /**
     * Stop the server if running and invoke the callback when complete.
     */
    @Override
    public void stop(Runnable callback) {
        stop();
        callback.run();
    }

    /**
     * Provide an {@link ErrorHandler} to be invoked if an Exception is thrown from the ZooKeeper server thread. If none
     * is provided, only error-level logging will occur.
     *
     * @param errorHandler the {@link ErrorHandler} to be invoked
     */
    public void setErrorHandler(ErrorHandler errorHandler) {
        this.errorHandler = errorHandler;
    }

    /**
     * Runnable implementation that starts the ZooKeeper server.
     */
    private class ServerRunnable implements Runnable {

        @Override
        public void run() {
            try {
                Properties properties = new Properties();
                File file = new File(System.getProperty("java.io.tmpdir")
                        + File.separator + UUID.randomUUID());
                file.deleteOnExit();
                properties.setProperty("dataDir", file.getAbsolutePath());
                properties.setProperty("clientPort", String.valueOf(clientPort));

                QuorumPeerConfig quorumPeerConfig = new QuorumPeerConfig();
                quorumPeerConfig.parseProperties(properties);

                zkServer = new ZooKeeperServerMain();
                ServerConfig configuration = new ServerConfig();
                configuration.readFrom(quorumPeerConfig);

                zkServer.runFromConfig(configuration);
            } catch (Exception e) {
                if (errorHandler != null) {
                    errorHandler.handleError(e);
                } else {
                    logger.error("Exception running embedded ZooKeeper", e);
                }
            }
        }
    }

}

dubbo-consumer.properties

dubbo.application.name=samples-annotation-consumer
dubbo.registry.address=zookeeper://${zookeeper.address:127.0.0.1}:2181
dubbo.consumer.timeout=1000

dubbo-provider.properties

dubbo.application.name=samples-annotation-provider
dubbo.registry.address=zookeeper://${zookeeper.address:127.0.0.1}:2181
dubbo.protocol.name=dubbo
dubbo.protocol.port=20880

log4j.properties

#
#
#   Licensed to the Apache Software Foundation (ASF) under one or more
#   contributor license agreements.  See the NOTICE file distributed with
#   this work for additional information regarding copyright ownership.
#   The ASF licenses this file to You under the Apache License, Version 2.0
#   (the "License"); you may not use this file except in compliance with
#   the License.  You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.
#
#

###set log levels###
log4j.rootLogger=info, stdout
###output to the console###
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=[%d{dd/MM/yy hh:mm:ss:sss z}] %t %5p %c{2}: %m%n