springboot druid 多数据源 示例

非常感谢您的提问。下面是 Spring Boot 和 Druid 多数据源的示例代码：

您需要添加以下 Maven 依赖：

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.1.21</version>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

然后，在 `application.yml` 中配置数据源：

spring:
  datasource:
    # 主数据源
    druid:
      url: jdbc:mysql://localhost:3306/main?useUnicode=true&characterEncoding=utf-8&autoReconnect=true
      username: root
      password: root
      driver-class-name: com.mysql.jdbc.Driver
      initialSize: 5
      minIdle: 5
      maxActive: 20
      maxWait: 60000
      timeBetweenEvictionRunsMillis: 60000
      minEvictableIdleTimeMillis: 300000
      validationQuery: select 1 from dual
      testWhileIdle: true
      testOnBorrow: false
      testOnReturn: false
      poolPreparedStatements: true
      maxPoolPreparedStatementPerConnectionSize: 20
      filters: stat,wall,log4j
      connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000

    # 第一个从数据源
    druid1:
      url: jdbc:mysql://localhost:3306/user_db?useUnicode=true&characterEncoding=utf-8&autoReconnect=true
      username: root
      password: root
      driver-class-name: com.mysql.jdbc.Driver
      initialSize: 5
      minIdle: 5
      maxActive: 20
      maxWait: 60000
      timeBetweenEvictionRunsMillis: 60000
      minEvictableIdleTimeMillis: 300000
      validationQuery: select 1 from dual
      testWhileIdle: true
      testOnBorrow: false
      testOnReturn: false
      poolPreparedStatements: true
      maxPoolPreparedStatementPerConnectionSize: 20
      filters: stat,wall,log4j
      connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000

    # 第二个从数据源
    druid2:
      url: jdbc:mysql://localhost:3306/other_db?useUnicode=true&characterEncoding=utf-8&autoReconnect=true
      username: root
      password: root
      driver-class-name: com.mysql.jdbc.Driver
      initialSize: 5
      minIdle: 5
      maxActive: 20
      maxWait: 60000
      timeBetweenEvictionRunsMillis: 60000
      minEvictableIdleTimeMillis: 300000
      validationQuery: select 1 from dual
      testWhileIdle: true
      testOnBorrow: false
      testOnReturn: false
      poolPreparedStatements: true
      maxPoolPreparedStatementPerConnectionSize: 20
      filters: stat,wall,log4j
      connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000

然后，在 Java 代码中配置数据源：

@Configuration
public class DataSourceConfig {

    @Bean
    @Primary
    @ConfigurationProperties("spring.datasource.druid")
    public DataSource mainDataSource() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    @ConfigurationProperties("spring.datasource.druid1")
    public DataSource dataSource1() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    @ConfigurationProperties("spring.datasource.druid2")
    public DataSource dataSource2() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean
    public DataSource dynamicDataSource(@Qualifier("mainDataSource") DataSource mainDataSource,
                                        @Qualifier("dataSource1") DataSource dataSource1,
                                        @Qualifier("dataSource2") DataSource dataSource2) {
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put(DataSourceType.MAIN, mainDataSource);
        targetDataSources.put(DataSourceType.DATA_SOURCE_1, dataSource1);
        targetDataSources.put(DataSourceType.DATA_SOURCE_2, dataSource2);
        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        dynamicDataSource.setTargetDataSources(targetDataSources);
        dynamicDataSource.setDefaultTargetDataSource(mainDataSource);
        return dynamicDataSource;
    }
}

其中，`DynamicDataSource` 是一个自定义的 `javax.sql.DataSource` 实现类，用于支持数据源的动态切换。最后，您就可以在代码中使用 `@Qualifier(DataSourceType.MAIN)`、`@Qualifier(DataSourceType.DATA_SOURCE_1)`、`@Qualifier(DataSourceType.DATA_SOURCE_2)` 等注解来区分使用不同的数据源了。

希望这个示例能够帮到您！