Dubbo入門案例

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Dubbo入門

簡介：

架構：

以上內容摘自dubbo-user

入門案例：

安裝ZooKeeper，這裏將用ZooKeeper作爲註冊中心，統一管理服務。（安裝步驟略）

安裝dubbo-admin監控中心（非必須，注:可自行網上查找可用於JDK8的war包，要不然會因爲環境問題無法再Tomcat中啓動）

創建服務提供者工程Dubbo-P

添加依賴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>

創建服務接口：DemoService.java

package cn.guyouda.dubbo.example;

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

服務提供者實現DemoService接口：DemoServiceImpl.java

package cn.guyouda.dubbo.example;

public class DemoServiceImpl implements DemoService {

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

}

創建配置文件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">
<!-- 提供方應用信息，用於計算依賴關係 -->
<dubbo:application name="hello-world-app" />
<!-- 使用multicast廣播註冊中心暴露服務地址 -->
<!--  <dubbo:registry address="multicast://224.5.6.7:1234" /> -->
<!--  -->
<dubbo:registry protocol="zookeeper" address="127.0.0.1:2181" />
<!-- 用dubbo協議在20880端口暴露服務 -->
<dubbo:protocol name="dubbo" port="20881" /> 
<!-- 聲明需要暴露的服務接口 -->
<dubbo:service interface="cn.guyouda.dubbo.example.DemoService" ref="demoService" />
<!-- 和本地bean一樣實現服務 -->
<bean id="demoService" class="cn.guyouda.dubbo.example.DemoServiceImpl" />
</beans>

啓動服務：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(); // 按任意鍵退出
		}

}

創建消費者工程Dubbo-C(結構如下)

引入依賴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>

創建服務接口DemoService.java（需和服務提供者接口保持一致）

package cn.guyouda.dubbo.example;

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

創建配置文件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">

<!-- 消費方應用名，用於計算依賴關係，不是匹配條件，不要與提供方一樣 -->
<dubbo:application name="consumer-of-helloworld-app" />

<!-- 使用multicast廣播註冊中心暴露發現服務地址 -->
  <!--<dubbo:registry address="multicast://224.5.6.7:1234" /> -->
<dubbo:registry protocol="zookeeper" address="127.0.0.1:2181"/>


<!-- 生成遠程服務代理，可以和本地bean一樣使用demoService -->
<dubbo:reference id="demoService" interface="cn.guyouda.dubbo.example.DemoService"/>

</beans>

啓動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"); // 獲取遠程服務代理
		String hello = demoService.sayHello("world"); // 執行遠程方法
		System.out.println( hello ); // 顯示調用結果
		}

}

注意：

1、建議打開兩個Eclipse分別運行兩個工程，要不然運行Dubbo-C的時候Dubbo-P會停了，導致出錯

2、新手運行Dubbo-P時極易遇見無法綁定，Dubbo端口20880佔用問題：第一次啓動就會綁定20880，再次啓動就會出現無法綁定，可以關閉相應進程；建議重新啓動的時候在provider.xml換一個端口20881，就不會出現之前的問題了。

3、一定要先啓動Dubbo-P，確定服務提供者已經正常啓動以後再啓動Dubbo-C