搭建基於springboot的dubbo專案踩坑記

lamar醬發表於2019-07-13

dubbo作為最常用的分散式框架之一,本人覺得很有必要自己搭建一個簡單的框架。

專案最終結構

搭建基於springboot的dubbo專案踩坑記
最外層為名為dubbo_demo的maven模組,內有基於springboot的生產者與消費者模組。

建立maven專案

使用idea新建maven專案,填入基本資訊。

搭建基於springboot的dubbo專案踩坑記
只保留pom.xml檔案,內容如下:

<?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>

    <!--子模組宣告-->
    <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>
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下面進行子模組的建立 :

搭建基於springboot的dubbo專案踩坑記
右擊專案名,新建Module,建立springboot專案。

provider

專案結構如下,包括與資料庫連線的dao,實體類model,以及服務service:

搭建基於springboot的dubbo專案踩坑記

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">
    <modelVersion>4.0.0</modelVersion>
    <!--父模組宣告-->
    <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>
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service

dubbo提供了服務方的宣告方式@Service,雖然和springboot的service宣告方式一樣,但是兩者引用的是不同的包。dubbo的包名為com.alibaba.dubbo.config.annotation.Service,不要導錯。

搭建基於springboot的dubbo專案踩坑記

屬性配置

#當前服務/應用的名字
dubbo.application.id=provider
dubbo.application.name=provider
dubbo.application.qos-enable=false
dubbo.scan.basePackages=com.lamarsan.provider.service.impl
#通訊規則(通訊協議和介面)
dubbo.protocol.id=dubbo
dubbo.protocol.name=dubbo
dubbo.protocol.port=12346
#註冊中心的協議和地址
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
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啟動項

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掃描的包
@MapperScan("com.lamarsan.provider.dao")
public class ProviderApplication {

    public static void main(String[] args) {
        SpringApplication.run(ProviderApplication.class, args);
    }

}

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consumer

專案結構如下,包括一個controller;

搭建基於springboot的dubbo專案踩坑記

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">
    <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依賴-->
        <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>

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controller

dubbo提供了@Reference註解,該註解可以替換@Autowired註解,用於引入遠端微服務,包名為 com.alibaba.dubbo.config.annotation.Reference

搭建基於springboot的dubbo專案踩坑記

屬性配置

# 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
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啟動項

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);
    }
    
}

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呼叫結果

先啟動provider模組,再啟動consumer模組,實現從資料庫讀取一個使用者資訊:

搭建基於springboot的dubbo專案踩坑記
以上就是全部的搭建流程。接下來是搭建過程中碰到的一些問題的解答。

踩坑環節

1)資料來源沒有自動配置

Failed to auto-configure a DataSource: 'spring.datasource.url' is not specified and no embedded datasource could be auto-configured.
提示資料來源沒有得到正確的配置。

解決方案1

在消費者啟動向中加入exclude = {DataSourceAutoConfiguration.class},如圖所示:

搭建基於springboot的dubbo專案踩坑記

解決方案2

將消費者模組的pom.xml中的有關mybatis與資料庫的依賴刪去即可。由於一開始並沒有注意這一細節,所以直接是從生產者的pom.xml中複製黏貼的,故報了這個錯。

2)服務方正確啟動,但是無法呼叫服務中的方法

No provider available from registry 127.0.0.1:2181 for service com.focussend.email.service.EdmTaskS
提示沒有可用的服務。 由於之前在@service(version="")中加入了版本資訊,但是消費者端並沒有定義,故出現了版本不一致的問題,所以無法正確啟動。

解決方案1

去掉@service括號裡的內容。

解決方案2

在消費者端定義dubbo.xml中的版本資訊。

3)資料庫繫結異常

org.apache.ibatis.binding.BindingException: Invalid bound statement (not found)
出現的錯誤網上是千篇一律的提示mapper.xml與dao層介面類的名字不一致以及namespace問題,也有提示沒有生成.xml檔案的問題,但都不適用於自己的情況。到最後才發現是配置項的宣告問題。

解決方案

在.properties檔案中加入: mybatis.mapper-locations = classpath*:mapper/*.xml一行,實現對map的掃描。

總結

之前一直使用別人已經搭建好的dubbo框架,自己搭建一套才發現坑真的不是一般的多,經常會踩一些別人認為理所當然會配置正確的坑,別看只有這麼三個異常,從開始搭建到搭建結束花了將近四個小時,瘋狂的查詢問題。但是這些坑都是有意義的,確實是讓我這個記憶力不好的人深深地記住了。

最後給出此專案的的gihub地址:github.com/lamarsan/du…

搭建基於springboot的dubbo專案踩坑記

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