搭建基於springboot的dubbo項目踩坑記

時間  2019-11-24
標籤 搭建 基於 springboot dubbo 項目 欄目 Spring 简体版
原文   原文鏈接

dubbo做爲最經常使用的分佈式框架之一，本人以爲頗有必要本身搭建一個簡單的框架。java

項目最終結構

最外層爲名爲dubbo_demo的maven模塊，內有基於springboot的生產者與消費者模塊。

建立maven項目

使用idea新建maven項目，填入基本信息。mysql

只保留pom.xml文件，內容以下： 

<?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>

    <!--子模塊聲明-->
    <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>
複製代碼

下面進行子模塊的建立 ：git

右擊項目名，新建Module，建立springboot項目。

provider

項目結構以下，包括與數據庫鏈接的dao，實體類model，以及服務service：github

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>
    <!--父模塊聲明-->
    <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>
複製代碼

service

dubbo提供了服務方的聲明方式@Service，雖然和springboot的service聲明方式同樣，可是二者引用的是不一樣的包。dubbo的包名爲com.alibaba.dubbo.config.annotation.Service，不要導錯。web

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（通訊協議和接口）
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
複製代碼

啓動項

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);
    }

}

複製代碼

consumer

項目結構以下,包括一個controller；spring

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>

複製代碼

controller

dubbo提供了@Reference註解，該註解能夠替換@Autowired註解，用於引入遠程微服務，包名爲 com.alibaba.dubbo.config.annotation.Referencesql

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
複製代碼

啓動項

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);
    }
    
}

複製代碼

調用結果

先啓動provider模塊，再啓動consumer模塊，實現從數據庫讀取一個用戶信息：數據庫

以上就是所有的搭建流程。接下來是搭建過程當中碰到的一些問題的解答。

踩坑環節

1）數據源沒有自動配置

Failed to auto-configure a DataSource: 'spring.datasource.url' is not specified and no embedded datasource could be auto-configured.
提示數據源沒有獲得正確的配置。apache

解決方案1

在消費者啓動向中加入exclude = {DataSourceAutoConfiguration.class},如圖所示：springboot

解決方案2

將消費者模塊的pom.xml中的有關mybatis與數據庫的依賴刪去便可。因爲一開始並無注意這一細節，因此直接是從生產者的pom.xml中複製黏貼的，故報了這個錯。

2）服務方正確啓動，可是沒法調用服務中的方法

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。 因爲以前在@service(version="")中加入了版本信息，可是消費者端並無定義，故出現了版本不一致的問題，因此沒法正確啓動。

解決方案1

去掉@service括號裏的內容。

解決方案2

在消費者端定義dubbo.xml中的版本信息。

3）數據庫綁定異常

org.apache.ibatis.binding.BindingException: Invalid bound statement (not found)
出現的錯誤網上是千篇一概的提示mapper.xml與dao層接口類的名字不一致以及namespace問題，也有提示沒有生成.xml文件的問題，但都不適用於本身的狀況。到最後才發現是配置項的聲明問題。

解決方案

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

總結

以前一直使用別人已經搭建好的dubbo框架，本身搭建一套才發現坑真的不是通常的多，常常會踩一些別人認爲理所固然會配置正確的坑，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，瘋狂的查找問題。可是這些坑都是有意義的，確實是讓我這個記憶力很差的人深深地記住了。

最後給出此項目的的gihub地址：github.com/lamarsan/du…

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