Dubbo入门案例

Dubbo入门

简介：

架构：

以上内容摘自dubbo-user

入门案例：

安装ZooKeeper，这里将用ZooKeeper作为注册中心，统一管理服务。（安装步骤略）

安装dubbo-admin监控中心（非必须，注:可自行网上查找可用于JDK8的war包，要不然会因为环境问题无法再Tomcat中启动）

创建服务提供者工程Dubbo-P

添加依赖jar包（pom.xml）

<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>cn.guyouda</groupId>
  <artifactId>Dubbo-P</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  
  
  <dependencies>
  
  	<!-- https://mvnrepository.com/artifact/com.alibaba/dubbo -->
	<dependency>
	    <groupId>com.alibaba</groupId>
	    <artifactId>dubbo</artifactId>
	    <version>2.5.3</version>
	</dependency>
	
	      <dependency>  
         <groupId>org.apache.zookeeper</groupId>  
			<artifactId>zookeeper</artifactId>  
			<version>3.4.6</version>  
     </dependency>  
  
   <dependency>  
     <groupId>com.github.sgroschupf</groupId>  
<artifactId>zkclient</artifactId>  
<version>0.1</version> 
</dependency>
  
  </dependencies>
  
  
</project>

创建服务接口：DemoService.java

package cn.guyouda.dubbo.example;

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

服务提供者实现DemoService接口：DemoServiceImpl.java

package cn.guyouda.dubbo.example;

public class DemoServiceImpl implements DemoService {

	public String sayHello(String name) {
		return "Hello," + name;
	}

}

创建配置文件provider.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd">
<!-- 提供方应用信息，用于计算依赖关系 -->
<dubbo:application name="hello-world-app" />
<!-- 使用multicast广播注册中心暴露服务地址 -->
<!--  <dubbo:registry address="multicast://224.5.6.7:1234" /> -->
<!--  -->
<dubbo:registry protocol="zookeeper" address="127.0.0.1:2181" />
<!-- 用dubbo协议在20880端口暴露服务 -->
<dubbo:protocol name="dubbo" port="20881" /> 
<!-- 声明需要暴露的服务接口 -->
<dubbo:service interface="cn.guyouda.dubbo.example.DemoService" ref="demoService" />
<!-- 和本地bean一样实现服务 -->
<bean id="demoService" class="cn.guyouda.dubbo.example.DemoServiceImpl" />
</beans>

启动服务：Provider.java

package cn.guyouda.dubbo.example;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Provider {
	
	public static void main(String[] args) throws Exception {
		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new
		String[] {"classpath:provider.xml"});
		context.start();
		System.out.println("Provider started");
		System.in.read(); // 按任意键退出
		}

}

创建消费者工程Dubbo-C(结构如下)

引入依赖pom.xml

<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>cn.guyouda</groupId>
  <artifactId>SB</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  
   <dependencies>
  
  	<!-- https://mvnrepository.com/artifact/com.alibaba/dubbo -->
	<dependency>
	    <groupId>com.alibaba</groupId>
	    <artifactId>dubbo</artifactId>
	    <version>2.5.3</version>
	</dependency>
	
	<!-- https://mvnrepository.com/artifact/com.101tec/zkclient -->
	<dependency>
	    <groupId>com.101tec</groupId>
	    <artifactId>zkclient</artifactId>
	    <version>0.10</version>
	</dependency>
	
  
  </dependencies>
  
</project>

创建服务接口DemoService.java（需和服务提供者接口保持一致）

package cn.guyouda.dubbo.example;

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

创建配置文件consumer.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd">

<!-- 消费方应用名，用于计算依赖关系，不是匹配条件，不要与提供方一样 -->
<dubbo:application name="consumer-of-helloworld-app" />

<!-- 使用multicast广播注册中心暴露发现服务地址 -->
  <!--<dubbo:registry address="multicast://224.5.6.7:1234" /> -->
<dubbo:registry protocol="zookeeper" address="127.0.0.1:2181"/>


<!-- 生成远程服务代理，可以和本地bean一样使用demoService -->
<dubbo:reference id="demoService" interface="cn.guyouda.dubbo.example.DemoService"/>

</beans>

启动Consumer.java

package cn.guyouda.dubbo.example;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Consumer {
	
	public static void main(String[] args) throws Exception {
		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(new
		String[] {"classpath:consumer.xml"});
		context.start();
		
		DemoService demoService = (DemoService)context.getBean("demoService"); // 获取远程服务代理
		String hello = demoService.sayHello("world"); // 执行远程方法
		System.out.println( hello ); // 显示调用结果
		}

}

注意：

1、建议打开两个Eclipse分别运行两个工程，要不然运行Dubbo-C的时候Dubbo-P会停了，导致出错

2、新手运行Dubbo-P时极易遇见无法绑定，Dubbo端口20880占用问题：第一次启动就会绑定20880，再次启动就会出现无法绑定，可以关闭相应进程；建议重新启动的时候在provider.xml换一个端口20881，就不会出现之前的问题了。

3、一定要先启动Dubbo-P，确定服务提供者已经正常启动以后再启动Dubbo-C