dubbo作为最常用的分布式框架之一,本人觉得很有必要自己搭建一个简单的框架。
最外层为名为dubbo_demo的maven模块,内有基于springboot的生产者与消费者模块。
使用idea新建maven项目,填入基本信息。
只保留pom.xml文件,内容如下:
<?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"> <modelVersion>4.0.0</modelVersion> <groupId>com.lamarsan</groupId> <artifactId>dubbo_demo</artifactId> <version>1.0-SNAPSHOT</version> <!--子模块声明--> <modules> <module> provider </module> <module> consumer </module> </modules> <properties> <java.version>1.8</java.version> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <dubbo.version>2.8.5-SNAPSHOT</dubbo.version> <curator-framework.version>1.3.3</curator-framework.version> <zookeeper.version>3.4.8</zookeeper.version> <zkclient.version>0.1</zkclient.version> <mybatis-starter.version>1.3.2</mybatis-starter.version> </properties> <dependencyManagement> <dependencies> <dependency> <groupId>com.alibaba.boot</groupId> <artifactId>dubbo-spring-boot-starter</artifactId> <version>0.2.0</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> <version>2.0.1.RELEASE</version> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>${mybatis-starter.version}</version> </dependency> <!-- zookeeper start --> <dependency> <groupId>com.netflix.curator</groupId> <artifactId>curator-framework</artifactId> <version>${curator-framework.version}</version> </dependency> <dependency> <groupId>org.apache.zookeeper</groupId> <artifactId>zookeeper</artifactId> <version>${zookeeper.version}</version> <exclusions> <exclusion> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> </exclusion> <exclusion> <artifactId>log4j-over-slf4j</artifactId> <groupId>org.slf4j</groupId> </exclusion> <exclusion> <artifactId>slf4j-log4j12</artifactId> <groupId>org.slf4j</groupId> </exclusion> <exclusion> <artifactId>log4j</artifactId> <groupId>log4j</groupId> </exclusion> </exclusions> </dependency> <dependency> <groupId>com.github.sgroschupf</groupId> <artifactId>zkclient</artifactId> <version>${zkclient.version}</version> </dependency> <!-- zookeeper end --> <dependency> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-resources-plugin</artifactId> <version>2.5</version> </dependency> <dependency> <groupId>commons-lang</groupId> <artifactId>commons-lang</artifactId> <version>2.6</version> </dependency> </dependencies> </dependencyManagement> <build> <resources> <resource> <directory>${basedir}/src/main/resources</directory> <filtering>true</filtering> <includes> <include>**/application*.yml</include> <include>**/*.properties</include> <include>**/*.xml</include> </includes> </resource> <resource> <directory>${basedir}/src/main/resources</directory> <includes> <include>**/application*.yml</include> <include>**/*.properties</include> <include>**/*.xml</include> </includes> </resource> </resources> </build> </project> 复制代码
下面进行子模块的创建 :
右击项目名,新建Module,创建springboot项目。
项目结构如下,包括与数据库连接的dao,实体类model,以及服务service:
<?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"> <modelVersion>4.0.0</modelVersion> <!--父模块声明--> <parent> <groupId>com.lamarsan</groupId> <artifactId>dubbo_demo</artifactId> <version>1.0-SNAPSHOT</version> </parent> <groupId>com.lamarsan</groupId> <artifactId>provider</artifactId> <version>0.0.1-SNAPSHOT</version> <name>provider</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> <version>2.0.1.RELEASE</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <version>2.0.1.RELEASE</version> <scope>test</scope> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> </dependency> <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.16</version> </dependency> <dependency> <groupId>com.alibaba.boot</groupId> <artifactId>dubbo-spring-boot-starter</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-configuration-processor</artifactId> <version>2.0.1.RELEASE</version> <optional>true</optional> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.16.18</version> <scope>provided</scope> </dependency> <dependency> <groupId>commons-lang</groupId> <artifactId>commons-lang</artifactId> <version>2.6</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project> 复制代码
dubbo提供了服务方的声明方式@Service,虽然和springboot的service声明方式一样,但是两者引用的是不同的包。dubbo的包名为com.alibaba.dubbo.config.annotation.Service,不要导错。
#当前服务/应用的名字 dubbo.application.id=provider dubbo.application.name=provider dubbo.application.qos-enable=false dubbo.scan.basePackages=com.lamarsan.provider.service.impl #通信规则(通信协议和接口) dubbo.protocol.id=dubbo dubbo.protocol.name=dubbo dubbo.protocol.port=12346 #注册中心的协议和地址 dubbo.registry.protocol=zookeeper dubbo.registry.address=xxxxx:2181 user.service.version=1.0.0 spring.datasource.url=jdbc:mysql://localhost:3306/debate?serverTimezone=GMT%2B8&&useCursorFetch=true&&characterEncoding=utf8 spring.datasource.username=root spring.datasource.password=root spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver mybatis.mapper-locations = classpath*:mapper/*.xml 复制代码
package com.lamarsan.provider; import com.alibaba.dubbo.config.spring.context.annotation.EnableDubbo; import org.mybatis.spring.annotation.MapperScan; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.context.annotation.ComponentScan; @SpringBootApplication @EnableDubbo @ComponentScan(basePackages = {"com.lamarsan.provider"}) //dubbo扫描的包 @MapperScan("com.lamarsan.provider.dao") public class ProviderApplication { public static void main(String[] args) { SpringApplication.run(ProviderApplication.class, args); } } 复制代码
项目结构如下,包括一个controller;
<?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"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>com.lamarsan</groupId> <artifactId>dubbo_demo</artifactId> <version>1.0-SNAPSHOT</version> </parent> <groupId>com.lamarsan</groupId> <artifactId>consumer</artifactId> <version>0.0.1-SNAPSHOT</version> <name>consumer</name> <description>Demo project for Spring Boot</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>com.lamarsan</groupId> <artifactId>provider</artifactId> <version>0.0.1-SNAPSHOT</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> <version>2.0.1.RELEASE</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <version>2.0.1.RELEASE</version> <scope>test</scope> </dependency> <!--引入web依赖--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> <version>2.0.1.RELEASE</version> </dependency> <dependency> <groupId>com.alibaba.boot</groupId> <artifactId>dubbo-spring-boot-starter</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-configuration-processor</artifactId> <version>2.0.1.RELEASE</version> <optional>true</optional> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.16.18</version> <scope>provided</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project> 复制代码
dubbo提供了@Reference注解,该注解可以替换@Autowired注解,用于引入远程微服务,包名为 com.alibaba.dubbo.config.annotation.Reference
# ApplicationConfig Bean dubbo.application.id = consumer dubbo.application.name = consumer dubbo.application.qos-enable = false dubbo.consumer.timeout=60000 dubbo.consumer.retries=0 server.port = 8098 # zookeeper ## ProtocolConfig Bean dubbo.protocol.id = dubbo dubbo.protocol.name = dubbo dubbo.registry.protocol = zookeeper dubbo.registry.address = xxxxx:2181 复制代码
package com.lamarsan.consumer; import com.alibaba.dubbo.config.spring.context.annotation.EnableDubbo; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.context.annotation.ComponentScan; @SpringBootApplication @EnableDubbo @ComponentScan(basePackages = {"com.lamarsan.consumer"}) public class ConsumerApplication { public static void main(String[] args) { SpringApplication.run(ConsumerApplication.class, args); } } 复制代码
先启动provider模块,再启动consumer模块,实现从数据库读取一个用户信息:
以上就是全部的搭建流程。接下来是搭建过程中碰到的一些问题的解答。
Failed to auto-configure a DataSource: 'spring.datasource.url' is not specified and no embedded datasource could be auto-configured.
提示数据源没有得到正确的配置。
在消费者启动向中加入 exclude = {DataSourceAutoConfiguration.class}
,如图所示:
将消费者模块的pom.xml中的有关mybatis与数据库的依赖删去即可。由于一开始并没有注意这一细节,所以直接是从生产者的pom.xml中复制黏贴的,故报了这个错。
No provider available from registry 127.0.0.1:2181 for service com.focussend.email.service.EdmTaskS
提示没有可用的服务。 由于之前在@service(version="")中加入了版本信息,但是消费者端并没有定义,故出现了版本不一致的问题,所以无法正确启动。
去掉@service括号里的内容。
在消费者端定义dubbo.xml中的版本信息。
org.apache.ibatis.binding.BindingException: Invalid bound statement (not found)
出现的错误网上是千篇一律的提示mapper.xml与dao层接口类的名字不一致以及namespace问题,也有提示没有生成.xml文件的问题,但都不适用于自己的情况。到最后才发现是配置项的声明问题。
在.properties文件中加入: mybatis.mapper-locations = classpath*:mapper/*.xml
一行,实现对map的扫描。
之前一直使用别人已经搭建好的dubbo框架,自己搭建一套才发现坑真的不是一般的多,经常会踩一些别人认为理所当然会配置正确的坑,别看只有这么三个异常,从开始搭建到搭建结束花了将近四个小时,疯狂的查找问题。但是这些坑都是有意义的,确实是让我这个记忆力不好的人深深地记住了。
最后给出此项目的的gihub地址: github.com/lamarsan/du…