Dubbo学习总结一
一、dubbo使用基本流程
- 新建服务接口
- 编写服务接口的实现类
- 注册服务的xml文件
- 编写启动服务测试类
- 新建消费Maven项目
- 创建相同路径相同的服务接口
- 消费服务的xml文件
- 编写启动消费服务的测试类
- 启动ZK，启动provider的测试类，向ZK注册服务
- 运行消费服务的测试类
二、dubbo使用，demo的具体实现
1. 新建服务接口
pom.xml引入一下jar包：
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>dubbo</artifactId>
<version>2.6.0</version>
</dependency>
<dependency>
<groupId>com.101tec</groupId>
<artifactId>zkclient</artifactId>
<version>0.10</version>
</dependency>
<dependency>
<groupId>org.apache.curator</groupId>
<artifactId>curator-framework</artifactId>
<version>4.0.1</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.46</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.25</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.4</version>
</dependency>
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.0.35.Final</version>
</dependency> 服务提供接口：
public interface DemoProviderService {
public String sayHello(String name);
} 2. 编写服务接口的实现类
public class DemoProviderServiceImpl implements DemoProviderService {
@Override
public String sayHello(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();
}
} 3. 注册服务的xml文件，写在src/main/resources文件夹下，名称 dubbo-demo-provider.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
xmlns="http://www.springframework.org/schema/beans"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd">
<!-- 服务提供者的应用名, 用来计算依赖关系 -->
<dubbo:application name="demo-provider"/>
<!-- 使用zookeeper注册中心暴露服务地址 -->
<dubbo:registry address="zookeeper://127.0.0.1:2181"/>
<!-- 使用dubbo协议，在20880端口暴露服务 -->
<dubbo:protocol name="dubbo" port="20880"/>
<!-- 服务的实现类, 本地类 -->
<bean id="demoProviderService" class="com.cslc.dubbo.service.impl.DemoProviderServiceImpl"/>
<!-- 申明要暴露的服务接口 -->
<dubbo:service interface="com.cslc.dubbo.service.DemoProviderService" ref="demoProviderService"/>
</beans> 4. 编写启动服务测试类
public class Provider {
public static void main(String[] args) {
//从类路径下读取XML文件生成上下文环境
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("dubbo-demo-provider.xml");
context.start();
System.out.println("服务提供者向zookeeper注册中心注册服务成功（端口：20880）");
try {
System.in.read();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
context.close();
}
} 5. 新建消费Maven项目
pom.xml文件中引入jar包：
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>dubbo</artifactId>
<version>2.6.0</version>
</dependency>
<dependency>
<groupId>com.101tec</groupId>
<artifactId>zkclient</artifactId>
<version>0.10</version>
</dependency>
<dependency>
<groupId>org.apache.curator</groupId>
<artifactId>curator-framework</artifactId>
<version>4.0.1</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.46</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.25</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.4</version>
</dependency>
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>4.0.35.Final</version>
</dependency> 6. 创建相同路径相同的服务接口
public interface DemoProviderService {
public String sayHello(String name);
} 7. 消费服务的xml文件，写在src/main/resources文件夹下，名称 dubbo-demo-consumer.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
xmlns="http://www.springframework.org/schema/beans"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd">
<!-- 消费方应用名, 用来计算依赖关系，不要与提供方的名称一样 -->
<dubbo:application name="demo-consumer"/>
<!-- 使用zookeeper注册中心暴露服务地址 -->
<dubbo:registry address="zookeeper://127.0.0.1:2181"/>
<!-- 使用dubbo协议，在20880端口暴露服务 -->
<dubbo:protocol name="dubbo" port="20880"/>
<!-- 生成远程服务代理，可以与本地的bean一样，check属性，启动的时候检查远程服务是否存在，一般设置为false，即使用的时候才去检查 -->
<dubbo:reference id="demoProviderService" check="false" interface="com.cslc.dubbo.service.DemoProviderService"/>
</beans> 8. 编写启动消费服务的测试类
public class Consumer {
public static void main(String[] args) {
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("dubbo-demo-consumer.xml");
context.start();
DemoProviderService demoProviderService=(DemoProviderService) context.getBean("demoProviderService");
String result=demoProviderService.sayHello("阿里");
System.out.println("远程调用的结果："+result);
try {
System.in.read();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
context.close();
}
} 9. 启动zookeeper，启动provider的测试类，向ZK注册服务
10.运行消费服务的测试类
附：
初学dubbo遇到的问题：
1. Exception in thread "main" org.springframework.beans.factory.parsing.BeanDefinitionParsingException: Configuration problem: Unable to locate Spring NamespaceHandler for XML schema namespace [http://dubbo.apache.org/schema/dubbo]
Offending resource: class path resource [dubbo-demo-provider.xml]
...... at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:614)
......原因：阿里把项目贡献给了Apache 原头文件中
http://dubbo.apache.org/schema/dubbo与http://dubbo.apache.org/schema/dubbo/dubbo.xsd 已失效
配置文件头更换一下：
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
xmlns="http://www.springframework.org/schema/beans"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd"> 2. Exception in thread "main" com.alibaba.dubbo.rpc.RpcException: No provider available from registry 127.0.0.1:2181 for service com.cslc.dubbo.DemoProviderService on consumer 172.20.29.235 use dubbo version 2.6.0, may be providers disabled or not registered ?
......原因：提供者/消费者没有对称的服务接口路径
3. 最后引用一下 初学Dubbo遇到的那些坑：
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