SpringBoot整合dubbo详述「建议收藏」

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环境：jdk1.8+springboot-2.2.1+dubbo-2.5.3+zookeeper-3.5.5+maven

构建工具:IDEA

我们知道，dubbo的本质就是一个远程服务调用的分布式框架。为了演示分布式架构的大致流程，我们项目里首先要建立对应的角色节点，即服务提供者、消费者以及公共接口服务，总体结构为:

SpringBoot整合dubbo详述「建议收藏」

dubbo_demo：是总项目
duboo-api：主要是实体类和接口服务
dubbo-customer：调用远程服务的服务消费方
duboo-provider：暴露服务的服务提供方

创建各个module的过程就不贴出来了，就是普通的springboot项目。需要注意的一点是在创建的时候每个module的GroupId要完全一致，否则在互相调用资源的时候会出现无法引入资源的问题。

一、dubbo_demo的pom.xml配置:

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.dubbo</groupId>
    <artifactId>dubbo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>dubbo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version>
        <zkclient.version>0.10</zkclient.version>
        <dubbo.version>2.5.3</dubbo.version>
    </properties>
    <modules>
        <!-- 主要放实体、接口、也可以放一些公用的工具类工程-->
        <module>dubbo-api</module>
        <!-- 服务消费者工程 -->
        <module>dubbo-customer</module>
        <!-- 服务提供者工程-->
        <module>dubbo-provider</module>
    </modules>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>dubbo</artifactId>
            <version>${dubbo.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>log4j</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>com.101tec</groupId>
            <artifactId>zkclient</artifactId>
            <version>${zkclient.version}</version>
        </dependency>


    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

由于dubbo的jar中也引入了spring依赖，所以在引入dubbo依赖时，需要将spring相关排除掉，否则会和项目本身的spring冲突。

即上面pom中的：

 <exclusion>
         <groupId>org.springframework</groupId>
         <artifactId>spring</artifactId>
 </exclusion>

二、接下来是dubbo-api的pom.xml配置,这个就比较简单了，这里不用引入dubbo等依赖：

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.dubbo</groupId>
    <artifactId>dubbo-api</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>dubbo-api</name>
    <description>Demo project for Spring Boot</description>
    <packaging>jar</packaging>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <finalName>dubbo-api</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

在dubbo-api中新建service包,添加测试接口

package com.dubbo.api.service;


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

三、1.dubbo-provider的pom.xml配置：

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.dubbo</groupId>
    <artifactId>provider</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>dubbo-provider</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <zkclient.version>0.10</zkclient.version>
        <dubbo.version>2.5.3</dubbo.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>com.dubbo</groupId>
            <artifactId>dubbo-api</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>dubbo</artifactId>
            <version>${dubbo.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>log4j</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <!-- zookeeper客户端 -->
        <dependency>
            <groupId>com.101tec</groupId>
            <artifactId>zkclient</artifactId>
            <version>${zkclient.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

2.创建TestService的实现类TestServiceImpl:

package com.dubbo.provider.impl;

import com.alibaba.dubbo.config.annotation.Service;
import com.dubbo.api.service.TestService;

@Service(version = "1.0.0",timeout = 3000)
 public class TestServiceImpl  implements TestService {

    @Override
     public String sayHello(String name) {
        return "哈哈哈，hello "+name;
    }
}

需要注意的是这里的@Service注解是dubbo的而不是spring的，不要用错了。

3.接下来在resources下创建spring-dubbo.xml文件，向zookeeper及dubbo注册并暴露服务

<?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">

    <!--服务名称-->
    <dubbo:application name="dubbo-provider"/>
    <!-- 注册中心的ip地址 -->
    <!-- 将服务提供者的地址暴露出去。这个过程通过zookeeper实现服务注册中心，进行注册暴露 -->
    <dubbo:registry address="zookeeper://192.168.4.54:2181"/>
    <!-- 扫描注解包路径，多个包用逗号分隔，不填pacakge表示扫描当前ApplicationContext中所有的类 -->
    <dubbo:annotation package="com.dubbo.provider.impl"/>

    <!-- 将服务提供者的端口号暴露出去 -->
    <dubbo:protocol name="dubbo" port="20880"/>

    <!-- service implementation, as same as regular local bean -->
    <bean id="testService" class="com.dubbo.provider.impl.TestServiceImpl"/>
    <!-- 将服务提供者需要对外提供的功能暴露出去 -->
    <dubbo:service interface="com.dubbo.api.service.TestService" ref="testService"/>

</beans>

4.application.yml 中配置服务端口号:

server:
 port: 9010

四、1.dubbo-customer的pom.xml配置文件:

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.dubbo</groupId>
    <artifactId>customer</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>customer</name>
    <description>Demo project for Spring Boot</description>
    <packaging>jar</packaging>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <zkclient.version>0.10</zkclient.version>
        <dubbo.version>2.5.3</dubbo.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>com.dubbo</groupId>
            <artifactId>dubbo-api</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>dubbo</artifactId>
            <version>${dubbo.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>log4j</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>com.101tec</groupId>
            <artifactId>zkclient</artifactId>
            <version>${zkclient.version}</version>
        </dependency>


        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <finalName>customer</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

2.创建消费端服务调用类 TestController

package com.dubbo.customer.controller;

import com.alibaba.dubbo.config.annotation.Reference;
import com.dubbo.api.service.TestService;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TestController {

    @Reference(version = "1.0.0",timeout = 300)
    private TestService testService;

    @RequestMapping("/sayHello")
    public String sayHello(@RequestParam String name) {
        System.out.println("name=="+name);
        System.out.println("testService=="+testService);
        return testService.sayHello(name);
    }





}

3.同样在resources下创建spring-dubbo.xml文件，配置注册中心地址等信息

<?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">

    <dubbo:application name="dubbo-consumer"/>
    <!-- 注册中心的ip地址 -->
    <dubbo:registry address="zookeeper://192.168.4.54:2181"/>
    <!-- 扫描注解包路径，多个包用逗号分隔，不填pacakge表示扫描当前ApplicationContext中所有的类 -->
    <dubbo:annotation package="com.dubbo.customer.controller"/>

    <!-- use dubbo protocol to export service on port 20880 -->
    <dubbo:protocol name="dubbo" port="20880"/>

    <dubbo:reference id="testService" check="false" interface="com.dubbo.api.service.TestService"/>

</beans>

4.application.yml 中配置服务端口号:

server:
 port: 9011

五、接下来就可以测试服务提供者和消费者是否能成功注册到dubbo上了，先启动放置dubbo-admin的tomcat以及zookeeper,再依次启动dubbo-provider和dubbo-customer服务，登录dubbo-admin控制台页面，可以看到provider和customer都已成功注册。

访问消费者服务customer也能成功调用provider

至此，所有流程算是成功了。下面说一下过程中遇到的一些问题。

构建过程中遇到的问题

1.最初在provider中调用com.dubbo.api.service.TestService类时一开始报错ClassNotFound,提示在dubbo-provider中找不到TestService，虽然我们在pom中已经引入了要调用的项目配置。经过各种调试，因为被调用者是dubbo-api module中的类，
最终我这里的解决方法是重新clean并编译一遍dubbo-api

然后执行Rebuild Project

再次强调，如果要想各个module相互调用，它们的GroupId必须是一致的。

2.通过执行以上操作，虽然在IDEA中没问题了，但是当我将dubbo-customer打成jar放到其它机器上运行时，又报了空指针异常，经调试发现原来是这里通过@Reference引入的testService为null

解决方法:

在被依赖项目dubbo-api的pom.xml文件spring-boot-maven-plugin依赖中加入配置<classifier>exec</classifier>,即:

 <build>
        <finalName>dubbo-api</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <classifier>exec</classifier>
                </configuration>
            </plugin>
        </plugins>
    </build>

另外，打包顺序也要注意，要先编译被依赖项dubbo-api，再编译dubbo-customer。

参考文章:

https://blog.csdn.net/qq_19419233/article/details/86678035#dubbo_1

https://www.cnblogs.com/gaopengfirst/p/9555240.html

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