Dubbo入门

引子

趁着五一的功夫搞了搞Jenkins布署和Dubbo，面试的时候总会问用过Dubbo没

前一家公司是做SpringCloud的微服务，所以就一直没有了解过这个技术，写个基础入门的教程留待备忘

Dubbo是什么？

Dubbo是阿里巴巴开源的一款高性能Java RPC框架 (远程服务调用的分布式框架)。旨在服务拆分后提供服务治理功能，目前已由Apache基金会维护

它提供了三大核心能力：面向接口的远程方法调用，智能容错和负载均衡，以及服务自动注册和发现。

它的架构如图：

了解SpringCloud的注册中心Eureka或Consul就会发现其功能很接近：

服务提供者将服务地址与方法参数注册到注册中心
服务消费者启动时订阅服务提供者的服务地址，服务提供者变更时注册中心将服务地址列表发给消费者
通过得到的地址调用服务接口返回结果，包含负载均衡，失败则调用其它
异步服务调用计数，用于监控各服务调用情况，如，调用时间/调用次数

其中第3步与Eureka和Consul的Http调用不同，Dubbo底层调用使用的是Netty建立的NIO通道，其高性能就在于此，即没有Http调用频繁开启关闭通道维护session和很多为了标识客户端状态的信息，通过非阻塞（NIO）长连接直接拿到业务数据

HelloWorld 01

以官方推荐Zookeeper注册中心为例，代码在https://github.com/HellxZ/DubboLearn.git 的master分支上

启动Zookeeper注册中心

下载最新的Zookeeper：Download

解压并进入解压缩后的文件夹下的conf目录，复制zoo_sample.cfg，创建新的配置

 cd zookeeper-3.4.14/conf
cp zoo_sample.cfg zoo.cfg
vim zoo.cfg

编辑zoo.cfg，按照Zookeeper官方推荐修改dataDir，选择自己想要的路径

保存修改退出

进入可执行文件目录，启动Zookeeper服务端

 cd ../bin
./zkServer.sh start #启动服务端

查看启动状态./zkServer.sh status，如下图即正常启动成功

查看Zookeeper日志tail -f zookeeper.out，在bin路径下的zookeeper.out，不要关闭终端方便观察

创建服务提供者

思路：使用两个Spring项目分别代表提供者与消费者，使用Dubbo注册到注册中心，不使用Tomcat以求配置最简化，展示xml全配置方式是如何操作

新建个Maven项目ServiceProvider，pom文件如下：

 <?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">
    <parent>
        <artifactId>XmlConfiguration</artifactId>
        <groupId>com.cnblogs.hellxz</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
 
    <artifactId>ServiceProvider</artifactId>
 
    <properties>
        <spring.version>4.1.4.RELEASE</spring.version>
        <log4j.version>1.2.17</log4j.version>
        <slf4j.version>1.7.7</slf4j.version>
    </properties>
 
    <dependencies>
        <!--spring 核心包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--spring上下文包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- 为了方便进行单元测试，添加spring-test包 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--添加spring-web包 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--spring切面包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--添加aspectjweaver包 -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.5</version>
        </dependency>
        <!-- 添加servlet3.0核心包 -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.0.1</version>
        </dependency>
        <!--日志包 -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <!-- 阿里巴巴fastjson包 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.1.41</version>
        </dependency>
        <!--阿里巴巴dubbo-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>dubbo</artifactId>
            <version>2.6.5</version>
        </dependency>
        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
            <version>3.4.6</version>
        </dependency>
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-recipes</artifactId>
            <version>2.7.0</version>
        </dependency>
        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.32.Final</version>
        </dependency>
 
    </dependencies>
 
    <build>
        <finalName>serviceProvider</finalName>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>
 
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

创建个服务接口与实现类

 package com.cnblogs.hellxz.service;
 
public interface IProviderService {
    String call();
}

 package com.cnblogs.hellxz.service.impl;
 
import com.cnblogs.hellxz.service.IProviderService;
 
public class ProviderServiceImpl implements IProviderService {
    @Override
    public String call() {
        //为了演示清楚，打印红色的输出，并非错误信息
        System.err.println("服务调用成功");
        return "Call service-provider success!";
    }
}

在resources下新建provider.xml，内容如下：

 <?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:context="http://www.springframework.org/schema/context"
       xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-4.0.xsd
    http://code.alibabatech.com/schema/dubbo
    http://code.alibabatech.com/schema/dubbo/dubbo.xsd"
>
    <!--仅保留核心配置-->
 
    <!--包扫描-->
    <context:component-scan base-package="com.cnblogs.hellxz"/>
 
    <!-- 提供方应用信息，用于计算依赖关系，请勿与其他服务名称相同 -->
    <dubbo:application name="service-provider"/>
    <!-- 使用zookeeper注册中心暴露服务地址，地址为zookeeper所在地址 -->
    <dubbo:registry protocol="zookeeper" address="127.0.0.1:2181"/>
 
    <!--指定要暴露的实现类-->
    <bean id="providerService" class="com.cnblogs.hellxz.service.impl.ProviderServiceImpl"/>
    <!--提供服务实现远程调用，消费者只需要有相同的接口即可调用-->
    <dubbo:service interface="com.cnblogs.hellxz.service.IProviderService" ref="providerService"/>
</beans>

log4j.properties

 #日志输出级别
log4j.rootLogger=INFO,stdout
#设置stdout的日志输出控制台
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
#输出日志到控制台的方式，默认为System.out
log4j.appender.stdout.Target=System.out
#设置使用灵活布局
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
#灵活定义输出格式
log4j.appender.stdout.layout.ConversionPattern=[%p][%d{yyyy-MM-dd HH:mm:ss}] %l %m %n

项目启动类ProviderMain

 package com.cnblogs.hellxz;
 
import org.springframework.context.support.ClassPathXmlApplicationContext;
import java.io.IOException;
 
/**
 * 服务提供者启动类
 */
public class ProviderMain {
    public static void main(String[] args) throws IOException {
        //读取配置文件，初始化Spring容器
        ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("provider.xml");
        //保持线程存活
        System.in.read();
    }
}

启动项目，我们观察到Zookeeper.out有日志出现了，即注册成功

创建服务消费者

结构如图：

pom文件：

 <?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">
    <parent>
        <artifactId>XmlConfiguration</artifactId>
        <groupId>com.cnblogs.hellxz</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
 
    <artifactId>Consumer</artifactId>
 
    <properties>
        <spring.version>4.1.4.RELEASE</spring.version>
        <log4j.version>1.2.17</log4j.version>
        <slf4j.version>1.7.7</slf4j.version>
    </properties>
 
    <dependencies>
        <!--spring 核心包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--spring上下文包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- 为了方便进行单元测试，添加spring-test包 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--添加spring-web包 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--spring切面包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--添加aspectjweaver包 -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.5</version>
        </dependency>
 
        <!-- log4j日志包 -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <!-- 阿里巴巴fastjson包 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.1.41</version>
        </dependency>
        <!--阿里巴巴dubbo-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>dubbo</artifactId>
            <version>2.6.5</version>
        </dependency>
        <!--解决Caused by: java.lang.ClassNotFoundException: org.apache.curator.framework.api.CuratorWatcher-->
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-recipes</artifactId>
            <version>2.7.0</version>
        </dependency>
        <!--解决java.lang.NoClassDefFoundError: io/netty/channel/nio/NioEventLoopGroup-->
        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.32.Final</version>
        </dependency>
    </dependencies>
 
    <build>
        <finalName>consumer</finalName>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>
 
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

pom文件中有些依赖没有会导致一些错误，本人已经将依赖添加的理由写上了，可以去除测试是否如实

log4j配置同提供者项目配置，如下是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:context="http://www.springframework.org/schema/context"
       xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-4.0.xsd
    http://code.alibabatech.com/schema/dubbo
    http://code.alibabatech.com/schema/dubbo/dubbo.xsd"
>
    <!--仅保留核心配置-->
 
    <!--包扫描-->
    <context:component-scan base-package="com.cnblogs.hellxz"/>
 
    <!-- 提供方应用信息，用于计算依赖关系，请勿与提供方相同 -->
    <dubbo:application name="service-consumer">
        <dubbo:parameter key="qos.enable" value="true"/>
        <dubbo:parameter key="qos.accept.foreign.ip" value="false"/>
        <!--
        报错java.net.BindException: 地址已在使用
        问题出现的原因：
            consumer启动时qos-server也是使用的默认的22222端口，但是这时候端口已经被provider给占用了，所以才会报错的。
        解决：指定新端口号
        -->
        <dubbo:parameter key="qos.port" value="33333"/>
    </dubbo:application>
 
    <!-- 
		指定注册中心使用的协议，这里使用zookeeper实现，地址为zookeeper的ip与端口
		如果不指定protocol，address可写为 address="zookeeper://127.0.0.1:2181"
	-->
    <dubbo:registry protocol="zookeeper" address="127.0.0.1:2181"/>
 
    <!-- 
		引用——通过rpc调用注册服务id为providerService的服务，通过这个设置我们就可以像调用本地方法一样调用
        需要注意的是：接口的包结构与类名，id均要与服务提供者完全相同，本人已测试
     -->
    <dubbo:reference interface="com.cnblogs.hellxz.service.IProviderService" id="providerService"/>
</beans>

调用服务提供者的方法接口的包路径、类名、方法名须与提供者完全相同

创建消费者项目启动类，演示一次调用。启动main方法

 package com.cnblogs.hellxz;
 
import com.cnblogs.hellxz.service.IProviderService;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
/**
 * 消费者启动类
 */
public class ConsumerMain {
    public static void main(String[] args) {
        //初始化spring容器
        ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("consumer.xml");
        //取出容器中的bean
        IProviderService providerService = (IProviderService)ctx.getBean("providerService");
        //打印调用结果 为了演示清楚，打印红色的输出，并非错误信息
        System.err.println(providerService.call());
    }
}

如图，调用成功

这里我们发现：如果我们调用一个方法，必须要写一个重复的接口类，如果服务提供者变更就可能出现不一致的问题，所以在下一个demo中把公共的接口抽取成一个模块，顺便把注解使用写在一起了

Hello World 02

与上一个demo区别：包含注解使用、抽取公共接口模块，代码在https://github.com/HellxZ/DubboLearn.git 的xml-base01分支上

这个分支是从上一个代码中checkout出来的，所以有部分全配置设置，这里只需关心带annotation的xml和启动方法就好

公共接口

与上个demo中服务接口相同，不上代码了，可以参考代码

服务提供者

pom.xml

 <?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">
    <parent>
        <artifactId>XmlConfiguration</artifactId>
        <groupId>com.cnblogs.hellxz</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
 
    <artifactId>ServiceProvider</artifactId>
 
    <properties>
        <spring.version>4.1.4.RELEASE</spring.version>
        <log4j.version>1.2.17</log4j.version>
        <slf4j.version>1.7.7</slf4j.version>
    </properties>
 
    <dependencies>
        <!--公用接口-->
        <dependency>
            <groupId>com.cnblogs.hellxz</groupId>
            <artifactId>CommonInterface</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <!--spring 核心包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--spring上下文包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- 为了方便进行单元测试，添加spring-test包 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--添加spring-web包 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--spring切面包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--添加aspectjweaver包 -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.5</version>
        </dependency>
        <!-- 添加servlet3.0核心包 -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.0.1</version>
        </dependency>
        <!--日志包 -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <!-- 阿里巴巴fastjson包 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.1.41</version>
        </dependency>
        <!--阿里巴巴dubbo-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>dubbo</artifactId>
            <version>2.6.5</version>
        </dependency>
        <!--解决使用注解出现ClassNotFoundException: com.alibaba.spring.beans.factory.annotation.AnnotationInjectedBeanPostProcessor-->
        <dependency>
            <groupId>com.alibaba.spring</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>1.0.2</version>
        </dependency>
        <!--zookeeper包-->
        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
            <version>3.4.6</version>
        </dependency>
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-recipes</artifactId>
            <version>2.7.0</version>
        </dependency>
        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.32.Final</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
 
    </dependencies>
 
    <build>
        <finalName>serviceProvider</finalName>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>
 
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

provider-annotation-config.xml

 <beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-4.0.xsd
    http://code.alibabatech.com/schema/dubbo
    http://code.alibabatech.com/schema/dubbo/dubbo.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd"
>
    <!--仅保留核心配置-->
 
    <!--开启切面编程自动代理-->
    <aop:aspectj-autoproxy proxy-target-class="true"/>
    <!--扫描注解生成bean-->
    <context:annotation-config/>
    <!--包扫描-->
    <context:component-scan base-package="com.cnblogs.hellxz"/>
 
    <!-- 提供方应用信息，用于计算依赖关系，请勿与其他服务名称相同 -->
    <dubbo:application name="service-provider"/>
    <!-- 使用zookeeper注册中心暴露服务地址，地址为zookeeper所在地址 -->
    <dubbo:registry protocol="zookeeper" address="127.0.0.1:2181"/>
 
    <dubbo:annotation package="com.cnblogs.hellxz"/>
</beans>

log4j日志配置不变，下面是ProviderMain

 package com.cnblogs.hellxz;
 
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
import java.io.IOException;
 
/**
 * 服务提供者启动类
 */
public class ProviderMain {
 
    /**
     * 以全配置方式启动spring容器，提供服务
     */
    @Test
    public void testFullXmlConfig() {
        initSpringContextWithConfigXml("provider-full-xml-config.xml");
    }
 
    /**
     * 使用配置方式开启注解，启动spring容器，提供服务
     */
    @Test
    public void testAnnotation() {
        initSpringContextWithConfigXml("provider-annotation-config.xml");
    }
 
    /**
     * 使用配置文件启动spring容器
     *
     * @param springConfigXmlName 配置文件在classPath下的路径名称
     */
    private void initSpringContextWithConfigXml(String springConfigXmlName) {
        //读取配置文件，初始化Spring容器
        ApplicationContext ctx = new ClassPathXmlApplicationContext(springConfigXmlName);
        try {
            //保持线程存活，输入任意字符回车停止
            System.in.read();
        } catch (IOException e) {
            //仅作演示不处理
            e.printStackTrace();
        }
    }
}

ProviderServiceImpl相对于Hello World 01中只是加了个@Service注解，但是注意这个注解是dubbo包下的

 package com.cnblogs.hellxz.service.impl;
 
import com.alibaba.dubbo.config.annotation.Service;
import com.cnblogs.hellxz.service.IProviderService;
 
@Service
public class ProviderServiceImpl implements IProviderService {
 
    @Override
    public String call() {
        //为了演示清楚，打印红色的输出，并非错误信息
        System.err.println("服务调用成功");
        return "Call service-provider success!";
    }
}

启动testAnnotation方法即可启动服务

请先关掉上个demo中启动的方法

服务消费者

pom.xml

 <?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">
    <parent>
        <artifactId>XmlConfiguration</artifactId>
        <groupId>com.cnblogs.hellxz</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
 
    <artifactId>Consumer</artifactId>
 
    <properties>
        <spring.version>4.1.4.RELEASE</spring.version>
        <log4j.version>1.2.17</log4j.version>
        <slf4j.version>1.7.7</slf4j.version>
    </properties>
 
    <dependencies>
        <!--spring 核心包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--spring上下文包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- 为了方便进行单元测试，添加spring-test包 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--添加spring-web包 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--spring切面包-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!--添加aspectjweaver包 -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.5</version>
        </dependency>
 
        <!-- log4j日志包 -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <!-- 阿里巴巴fastjson包 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.1.41</version>
        </dependency>
        <!--阿里巴巴dubbo-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>dubbo</artifactId>
            <version>2.6.5</version>
        </dependency>
        <!--解决Caused by: java.lang.ClassNotFoundException: org.apache.curator.framework.api.CuratorWatcher-->
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-recipes</artifactId>
            <version>2.7.0</version>
        </dependency>
        <!--解决java.lang.NoClassDefFoundError: io/netty/channel/nio/NioEventLoopGroup-->
        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.32.Final</version>
        </dependency>
        <!--添加公用接口模块-->
        <dependency>
            <groupId>com.cnblogs.hellxz</groupId>
            <artifactId>CommonInterface</artifactId>
            <version>1.0-SNAPSHOT</version>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
        <!--解决使用注解出现ClassNotFoundException: com.alibaba.spring.beans.factory.annotation.AnnotationInjectedBeanPostProcessor-->
        <dependency>
            <groupId>com.alibaba.spring</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>1.0.2</version>
        </dependency>
    </dependencies>
 
    <build>
        <finalName>consumer</finalName>
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>
 
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

consumer-annotation-config.xml

 <beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:dubbo="http://code.alibabatech.com/schema/dubbo" xmlns:aop="http://www.springframework.org/schema/aop"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-4.0.xsd
    http://code.alibabatech.com/schema/dubbo
    http://code.alibabatech.com/schema/dubbo/dubbo.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd"
>
    <!--仅保留核心配置-->
 
    <!--开启切面编程自动代理-->
    <aop:aspectj-autoproxy proxy-target-class="true"/>
    <!--包扫描-->
    <context:component-scan base-package="com.cnblogs.hellxz"/>
    <!--扫描注解生成bean-->
    <context:annotation-config/>
 
    <!-- 提供方应用信息，用于计算依赖关系，请勿与提供方相同 -->
    <dubbo:application name="service-consumer">
        <dubbo:parameter key="qos.enable" value="true"/>
        <dubbo:parameter key="qos.accept.foreign.ip" value="false"/>
        <!--
        报错java.net.BindException: 地址已在使用
        问题出现的原因：
            consumer启动时qos-server也是使用的默认的22222端口，但是这时候端口已经被provider给占用了，所以才会报错的。
        解决：指定新端口号
        -->
        <dubbo:parameter key="qos.port" value="33333"/>
    </dubbo:application>
 
    <!-- 使用zookeeper注册中心暴露服务地址，地址为zookeeper所在地址 -->
    <dubbo:registry protocol="zookeeper" address="127.0.0.1:2181"/>
 
    <dubbo:annotation package="com.cnblogs.hellxz"/>
</beans>

需要有一个bean在spring容器中对应Dubbo引用的接口上

 package com.cnblogs.hellxz.service.impl;
 
import com.alibaba.dubbo.config.annotation.Reference;
import com.cnblogs.hellxz.service.IProviderService;
import org.springframework.stereotype.Service;
 
/**
 * 这个类主要作用就是dubbo引用的接口与providerService这个bean名称作绑定
 * 在全xml配置方式中无需存在，注意这回的@Service注解是spring的
 */
@Service("providerService")
public class ProviderServiceImpl implements IProviderService {
 
    @Reference
    private IProviderService iProviderService;
 
    @Override
    public String call() {
        return iProviderService.call();
    }
}

注意事项：

这回的@Service注解是spring的

使用Springmvc时无需再包这一层，在@Controller或@RestController的类中直接写@Reference就可以了

贴出启动方法，这次用的是Junit测试的

     @Test
    public void testAnnotationConfig() {
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("consumer-annotation-config.xml");
        IProviderService providerService = (IProviderService) context.getBean("providerService");
        System.err.println(providerService.call());
    }

测试结果与Demo01相同

报错与解决

1.在注册中心找不到对应的服务

 java.lang.IllegalStateException: Failed to check the status of the service *.*.*.xxService . No provider available for the service *.*.*.xxService

这个错误原因是服务端没有将xxService服务注册到注册中心，原因无非三种

没加com.alibaba.dubbo.config.annotation包下的@Service注解或引错包;
服务端没启动起来，检查服务端状态
服务端没注册到注册中心，检查服务端测试中心配置

2. 无法连接到注册中心

检查Zookeeper是否正常运行
检查报错项目的注册中心地址配置

3. ClassNotFound异常

3.1

 Caused by: java.lang.ClassNotFoundException: org.apache.curator.framework.api.CuratorWatcher

添加依赖

         <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-recipes</artifactId>
            <version>2.7.0</version>
        </dependency>

3.2

 ClassNotFoundException: com.alibaba.spring.beans.factory.annotation.AnnotationInjectedBeanPostProcessor

添加依赖

         <dependency>
            <groupId>com.alibaba.spring</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>1.0.2</version>
        </dependency>

4. NoClassDefFoundError错误

 java.lang.NoClassDefFoundError: io/netty/channel/nio/NioEventLoopGroup

添加依赖

         <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.32.Final</version>
        </dependency>

5. java.net.BindException: 地址已在使用

     <!-- 提供方应用信息，用于计算依赖关系，请勿与提供方相同 -->
    <dubbo:application name="service-consumer">
        <dubbo:parameter key="qos.enable" value="true"/>
        <dubbo:parameter key="qos.accept.foreign.ip" value="false"/>
        <!--
        报错java.net.BindException: 地址已在使用
        问题出现的原因：
            consumer启动时qos-server也是使用的默认的22222端口，但是这时候端口已经被provider给占用了，所以才会报错的。
        解决：指定新端口号
        -->
        <dubbo:parameter key="qos.port" value="33333"/>
    </dubbo:application>

最后

与SpringBoot的集成的版本后续会开发到新分支下，本文仅介绍Dubbo的架构与基础用法

欢迎关注点赞评论转载，比B站多一连 😃，您的支持就是我的动力

本文为实操笔记，转载请注明出处

本文作者：东北小狐狸

本文链接：https://www.cnblogs.com/hellxz/p/10808753.html

posted @ 2019-05-04 16:13 东北小狐狸阅读(1316) 评论(0) 编辑收藏举报

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Hellxz博客

「若你不能简单解释一件事，那么就是你不够了解它。」

Dubbo入门

引子

Dubbo是什么？

HelloWorld 01

启动Zookeeper注册中心

创建服务提供者

创建服务消费者

Hello World 02

公共接口

服务提供者

服务消费者

报错与解决

1.在注册中心找不到对应的服务

2. 无法连接到注册中心

3. ClassNotFound异常

3.1

3.2

4. NoClassDefFoundError错误

5. java.net.BindException: 地址已在使用

最后

公告

积分与排名

随笔分类 (353)

随笔档案 (339)

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阅读排行榜

推荐排行榜

	cd zookeeper-3.4.14/conf
	cp zoo_sample.cfg zoo.cfg
	vim zoo.cfg

	<?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">
	<parent>
	<artifactId>XmlConfiguration</artifactId>
	<groupId>com.cnblogs.hellxz</groupId>
	<version>1.0-SNAPSHOT</version>
	</parent>
	<modelVersion>4.0.0</modelVersion>

	<artifactId>ServiceProvider</artifactId>

	<properties>
	<spring.version>4.1.4.RELEASE</spring.version>
	<log4j.version>1.2.17</log4j.version>
	<slf4j.version>1.7.7</slf4j.version>
	</properties>

	<dependencies>
	<!--spring 核心包-->
	<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-core</artifactId>
	<version>${spring.version}</version>
	</dependency>
	<!--spring上下文包-->
	<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-context</artifactId>
	<version>${spring.version}</version>
	</dependency>
	<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-context-support</artifactId>
	<version>${spring.version}</version>
	</dependency>
	<!-- 为了方便进行单元测试，添加spring-test包 -->
	<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-test</artifactId>
	<version>${spring.version}</version>
	</dependency>
	<!--添加spring-web包 -->
	<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-web</artifactId>
	<version>${spring.version}</version>
	</dependency>
	<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-webmvc</artifactId>
	<version>${spring.version}</version>
	</dependency>
	<!--spring切面包-->
	<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-aop</artifactId>
	<version>${spring.version}</version>
	</dependency>
	<!--添加aspectjweaver包 -->
	<dependency>
	<groupId>org.aspectj</groupId>
	<artifactId>aspectjweaver</artifactId>
	<version>1.8.5</version>
	</dependency>
	<!-- 添加servlet3.0核心包 -->
	<dependency>
	<groupId>javax.servlet</groupId>
	<artifactId>javax.servlet-api</artifactId>
	<version>3.0.1</version>
	</dependency>
	<!--日志包 -->
	<dependency>
	<groupId>log4j</groupId>
	<artifactId>log4j</artifactId>
	<version>${log4j.version}</version>
	</dependency>
	<dependency>
	<groupId>org.slf4j</groupId>
	<artifactId>slf4j-api</artifactId>
	<version>${slf4j.version}</version>
	</dependency>
	<dependency>
	<groupId>org.slf4j</groupId>
	<artifactId>slf4j-log4j12</artifactId>
	<version>${slf4j.version}</version>
	</dependency>
	<!-- 阿里巴巴fastjson包 -->
	<dependency>
	<groupId>com.alibaba</groupId>
	<artifactId>fastjson</artifactId>
	<version>1.1.41</version>
	</dependency>
	<!--阿里巴巴dubbo-->
	<dependency>
	<groupId>com.alibaba</groupId>
	<artifactId>dubbo</artifactId>
	<version>2.6.5</version>
	</dependency>
	<dependency>
	<groupId>org.apache.zookeeper</groupId>
	<artifactId>zookeeper</artifactId>
	<version>3.4.6</version>
	</dependency>
	<dependency>
	<groupId>org.apache.curator</groupId>
	<artifactId>curator-recipes</artifactId>
	<version>2.7.0</version>
	</dependency>
	<dependency>
	<groupId>io.netty</groupId>
	<artifactId>netty-all</artifactId>
	<version>4.1.32.Final</version>
	</dependency>

	</dependencies>

	<build>
	<finalName>serviceProvider</finalName>
	<resources>
	<resource>
	<directory>src/main/java</directory>
	<includes>
	<include>*/.xml</include>
	</includes>
	</resource>
	</resources>

	<plugins>
	<plugin>
	<groupId>org.apache.maven.plugins</groupId>
	<artifactId>maven-compiler-plugin</artifactId>
	<configuration>
	<source>1.8</source>
	<target>1.8</target>
	</configuration>
	</plugin>
	</plugins>
	</build>
	</project>

	package com.cnblogs.hellxz.service;

	public interface IProviderService {
	String call();
	}

	package com.cnblogs.hellxz.service.impl;

	import com.cnblogs.hellxz.service.IProviderService;

	public class ProviderServiceImpl implements IProviderService {
	@Override
	public String call() {
	//为了演示清楚，打印红色的输出，并非错误信息
	System.err.println("服务调用成功");
	return "Call service-provider success!";
	}
	}

	<?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:context="http://www.springframework.org/schema/context"
	xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
	http://www.springframework.org/schema/context
	http://www.springframework.org/schema/context/spring-context-4.0.xsd
	http://code.alibabatech.com/schema/dubbo
	http://code.alibabatech.com/schema/dubbo/dubbo.xsd"
	>
	<!--仅保留核心配置-->

	<!--包扫描-->
	<context:component-scan base-package="com.cnblogs.hellxz"/>

	<!-- 提供方应用信息，用于计算依赖关系，请勿与其他服务名称相同 -->
	<dubbo:application name="service-provider"/>
	<!-- 使用zookeeper注册中心暴露服务地址，地址为zookeeper所在地址 -->
	<dubbo:registry protocol="zookeeper" address="127.0.0.1:2181"/>

	<!--指定要暴露的实现类-->
	<bean id="providerService" class="com.cnblogs.hellxz.service.impl.ProviderServiceImpl"/>
	<!--提供服务实现远程调用，消费者只需要有相同的接口即可调用-->
	<dubbo:service interface="com.cnblogs.hellxz.service.IProviderService" ref="providerService"/>
	</beans>

	#日志输出级别
	log4j.rootLogger=INFO,stdout
	#设置stdout的日志输出控制台
	log4j.appender.stdout=org.apache.log4j.ConsoleAppender
	#输出日志到控制台的方式，默认为System.out
	log4j.appender.stdout.Target=System.out
	#设置使用灵活布局
	log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
	#灵活定义输出格式
	log4j.appender.stdout.layout.ConversionPattern=[%p][%d{yyyy-MM-dd HH:mm:ss}] %l %m %n

	package com.cnblogs.hellxz;

	import org.springframework.context.support.ClassPathXmlApplicationContext;
	import java.io.IOException;

	/**
	* 服务提供者启动类
	*/
	public class ProviderMain {
	public static void main(String[] args) throws IOException {
	//读取配置文件，初始化Spring容器
	ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("provider.xml");
	//保持线程存活
	System.in.read();
	}
	}

	package com.cnblogs.hellxz;

	import org.junit.Test;
	import org.springframework.context.ApplicationContext;
	import org.springframework.context.support.ClassPathXmlApplicationContext;

	import java.io.IOException;

	/**
	* 服务提供者启动类
	*/
	public class ProviderMain {

	/**
	* 以全配置方式启动spring容器，提供服务
	*/
	@Test
	public void testFullXmlConfig() {
	initSpringContextWithConfigXml("provider-full-xml-config.xml");
	}

	/**
	* 使用配置方式开启注解，启动spring容器，提供服务
	*/
	@Test
	public void testAnnotation() {
	initSpringContextWithConfigXml("provider-annotation-config.xml");
	}

	/**
	* 使用配置文件启动spring容器
	*
	* @param springConfigXmlName 配置文件在classPath下的路径名称
	*/
	private void initSpringContextWithConfigXml(String springConfigXmlName) {
	//读取配置文件，初始化Spring容器
	ApplicationContext ctx = new ClassPathXmlApplicationContext(springConfigXmlName);
	try {
	//保持线程存活，输入任意字符回车停止
	System.in.read();
	} catch (IOException e) {
	//仅作演示不处理
	e.printStackTrace();
	}
	}
	}

	package com.cnblogs.hellxz.service.impl;

	import com.alibaba.dubbo.config.annotation.Service;
	import com.cnblogs.hellxz.service.IProviderService;

	@Service
	public class ProviderServiceImpl implements IProviderService {

	@Override
	public String call() {
	//为了演示清楚，打印红色的输出，并非错误信息
	System.err.println("服务调用成功");
	return "Call service-provider success!";
	}
	}

	@Test
	public void testAnnotationConfig() {
	ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("consumer-annotation-config.xml");
	IProviderService providerService = (IProviderService) context.getBean("providerService");
	System.err.println(providerService.call());
	}

	Caused by: java.lang.ClassNotFoundException: org.apache.curator.framework.api.CuratorWatcher

	<dependency>
	<groupId>com.alibaba.spring</groupId>
	<artifactId>spring-context-support</artifactId>
	<version>1.0.2</version>
	</dependency>

	<!-- 提供方应用信息，用于计算依赖关系，请勿与提供方相同 -->
	<dubbo:application name="service-consumer">
	<dubbo:parameter key="qos.enable" value="true"/>
	<dubbo:parameter key="qos.accept.foreign.ip" value="false"/>
	<!--
	报错java.net.BindException: 地址已在使用
	问题出现的原因：
	consumer启动时qos-server也是使用的默认的22222端口，但是这时候端口已经被provider给占用了，所以才会报错的。
	解决：指定新端口号
	-->
	<dubbo:parameter key="qos.port" value="33333"/>
	</dubbo:application>