SpringCloud + MyBatis Plus + Druid + dynamic-datasource 多数据源配置

上下文：

SpringCloud：Greenwich.SR2

Spring-boot ： 2.1.7.RELEASE

Spring：5.1.9.RELEASE

依赖：

<!--DB start-->
<!--多数据源依赖-->
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
    <version>3.2.1</version>
</dependency>
<!--mybatis-plus依赖-->
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.4.1</version>
</dependency>
<!--MySQL依赖 -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.22</version>
</dependency>
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.2.3</version>
</dependency>

<!--代码生成start-->
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-generator</artifactId>
    <version>3.4.1</version>
    <scope>compile</scope>
    <optional>true</optional>
</dependency>
<!-- 模板引擎start -->
<dependency>
    <groupId>org.apache.velocity</groupId>
    <artifactId>velocity-engine-core</artifactId>
    <version>2.2</version>
    <scope>compile</scope>
    <optional>true</optional>
</dependency>
<dependency>
    <groupId>org.freemarker</groupId>
    <artifactId>freemarker</artifactId>
    <version>2.3.30</version>
    <scope>compile</scope>
    <optional>true</optional>
</dependency>
<!-- 模板引擎end -->
<!--代码生成end-->
<!--DB end-->

配置文件application.yml

spring:
  autoconfigure:
    #自动化配置 例外处理
    exclude: com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceAutoConfigure
  # dynamic-datasource-spring-boot-starter 动态数据源的配置内容
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    dynamic:
      primary: test # 设置默认的数据源或者数据源组，默认值即为 master
      datasource:
        # test 数据源配置
        test:
          url: jdbc:mysql://192.168.1.120:3306/db_test?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
          driver-class-name: com.mysql.cj.jdbc.Driver
          username: root
          password: root1234
        # test1 数据源配置
        test1:
          url: jdbc:mysql://192.168.1.120:3306/db_test1?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
          driver-class-name: com.mysql.cj.jdbc.Driver
          username: root
          password: root1234
        # test2 数据源配置
        test2:
          url: jdbc:mysql://192.168.1.120:3306/db_test2?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
          driver-class-name: com.mysql.cj.jdbc.Driver
          username: root
          password: root1234
      #dynamic - 公共配置
      druid:
        initialSize: 5
        minIdle: 5
        maxActive: 30
        maxWait: 60000
        timeBetweenEvictionRunsMillis: 60000
        minEvictableIdleTimeMillis: 300000
        validationQuery: SELECT 'x'
        testWhileIdle: true
        testOnBorrow: false
        testOnReturn: false
        poolPreparedStatements: true
        maxPoolPreparedStatementPerConnectionSize: 20
        filters: stat,wall,slf4j,config
        useGlobalDataSourceStat: true
        stat:
          log-slow-sql: true
          merge-sql: true
          slow-sql-millis: 10000


mybatis-plus:
  type-aliases-package: com.*
  mapper-locations: classpath*:mapper/*.xml

如果没有设置上文红色部分配置，请在启动类的 SpringBootApplication 注解上加入过滤配置：

@SpringBootApplication(exclude = DruidDataSourceAutoConfigure.class)
public class Application {

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

}

不加过滤的话，SpringBoo t会自动检测到启动了database模块，会报如下问题：

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/alibaba/druid/spring/boot/autoconfigure/DruidDataSourceAutoConfigure.class]: Invocation of init method failed; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1778)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:593)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515)
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:277)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.addCandidateEntry(DefaultListableBeanFactory.java:1467)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1431)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveMultipleBeans(DefaultListableBeanFactory.java:1350)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1209)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1171)
    at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:857)
    at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:760)
    ... 117 common frames omitted
Caused by: org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class
    at org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.determineDriverClassName(DataSourceProperties.java:233)
    at org.springframework.boot.autoconfigure.jdbc.DataSourceProperties.determineUsername(DataSourceProperties.java:327)
    at com.alibaba.druid.spring.boot.autoconfigure.DruidDataSourceWrapper.afterPropertiesSet(DruidDataSourceWrapper.java:40)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1837)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1774)
    ... 131 common frames omitted
2020-11-19 15:34:16.885[main]|INFO|org.eclipse.jetty.server.handler.ContextHandler - Stopped o.s.b.w.e.j.JettyEmbeddedWebAppContext@455d04d2{application,/,[file:///C:/Users/Administrator.USER-20190109GW/AppData/Local/Temp/jetty-docbase.2008797717949458032.12394/, jar:file:/D:/Server/maven/repository/io/springfox/springfox-swagger-ui/2.9.2/springfox-swagger-ui-2.9.2.jar!/META-INF/resources],UNAVAILABLE}
2020-11-19 15:34:16.886[main]|WARN|o.s.b.w.s.c.AnnotationConfigServletWebServerApplicationContext - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Jetty web server
2020-11-19 15:34:16.901[main]|INFO|o.s.b.a.l.ConditionEvaluationReportLoggingListener - 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2020-11-19 15:34:16.905[main]|ERROR|o.s.b.diagnostics.LoggingFailureAnalysisReporter - 

***************************
APPLICATION FAILED TO START
***************************

Description:

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.

Reason: Failed to determine a suitable driver class


Action:

Consider the following:
    If you want an embedded database (H2, HSQL or Derby), please put it on the classpath.
    If you have database settings to be loaded from a particular profile you may need to activate it (no profiles are currently active).

Disconnected from the target VM, address: '127.0.0.1:14992', transport: 'socket'

Process finished with exit code 1

用法：在service实现层 或者 方法上 添加注解@DS("你的db key")，选定数据源，如：

@DS("test")
@Service("userService")
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService {

}

PS：

mybatis plus + druid多数据源（使用dynamic实现）

Springboot mybatis plus druid多数据源解决方案 dynamic-datasource的使用

https://gitee.com/hejr.cn.com/SpringBoot2.0_2019/blob/master/springboot2_004/pom.xml

https://github.com/baomidou/dynamic-datasource-spring-boot-starter/blob/master/pom.xml