在 Spring Boot 应用中配置多个 Druid 数据源是常见的需求，特别是在需要连接多个数据库的场景下。以下是完整的配置方法和最佳实践。

一、基础配置步骤

1. 添加依赖

首先确保 pom.xml 中包含必要的依赖：

xml

复制

下载

运行

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.2.8</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

2. 配置 application.yml

yaml

复制

下载

spring:
  datasource:
    # 主数据源
    primary:
      type: com.alibaba.druid.pool.DruidDataSource
      driver-class-name: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://localhost:3306/primary_db
      username: root
      password: 123456
      druid:
        initial-size: 5
        max-active: 20
        min-idle: 5
        max-wait: 60000
    
    # 从数据源
    secondary:
      type: com.alibaba.druid.pool.DruidDataSource
      driver-class-name: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://localhost:3306/secondary_db
      username: root
      password: 123456
      druid:
        initial-size: 3
        max-active: 15
        min-idle: 3
        max-wait: 30000

二、Java 配置类实现

1. 主数据源配置

java

复制

下载

@Configuration
public class DataSourceConfig {

    @Primary
    @Bean(name = "primaryDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.primary")
    public DataSource primaryDataSource() {
        return DruidDataSourceBuilder.create().build();
    }

    @Bean(name = "secondaryDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.secondary")
    public DataSource secondaryDataSource() {
        return DruidDataSourceBuilder.create().build();
    }
}

2. 配置事务管理器

java

复制

下载

@Configuration
@EnableTransactionManagement
public class TransactionConfig {

    @Bean
    @Primary
    public PlatformTransactionManager primaryTransactionManager(
            @Qualifier("primaryDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }

    @Bean
    public PlatformTransactionManager secondaryTransactionManager(
            @Qualifier("secondaryDataSource") DataSource dataSource) {
        return new DataSourceTransactionManager(dataSource);
    }
}

三、MyBatis 多数据源配置

1. 主数据源 MyBatis 配置

java

复制

下载

@Configuration
@MapperScan(basePackages = "com.example.mapper.primary",
           sqlSessionFactoryRef = "primarySqlSessionFactory")
public class PrimaryMyBatisConfig {

    @Primary
    @Bean(name = "primarySqlSessionFactory")
    public SqlSessionFactory primarySqlSessionFactory(
            @Qualifier("primaryDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(
            new PathMatchingResourcePatternResolver()
                .getResources("classpath:mapper/primary/*.xml"));
        return bean.getObject();
    }

    @Primary
    @Bean(name = "primarySqlSessionTemplate")
    public SqlSessionTemplate primarySqlSessionTemplate(
            @Qualifier("primarySqlSessionFactory") SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

2. 从数据源 MyBatis 配置

java

复制

下载

@Configuration
@MapperScan(basePackages = "com.example.mapper.secondary",
           sqlSessionFactoryRef = "secondarySqlSessionFactory")
public class SecondaryMyBatisConfig {

    @Bean(name = "secondarySqlSessionFactory")
    public SqlSessionFactory secondarySqlSessionFactory(
            @Qualifier("secondaryDataSource") DataSource dataSource) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSource);
        bean.setMapperLocations(
            new PathMatchingResourcePatternResolver()
                .getResources("classpath:mapper/secondary/*.xml"));
        return bean.getObject();
    }

    @Bean(name = "secondarySqlSessionTemplate")
    public SqlSessionTemplate secondarySqlSessionTemplate(
            @Qualifier("secondarySqlSessionFactory") SqlSessionFactory sqlSessionFactory) {
        return new SqlSessionTemplate(sqlSessionFactory);
    }
}

四、JPA/Hibernate 多数据源配置

1. 主数据源 JPA 配置

java

复制

下载

@Configuration
@EnableJpaRepositories(
    basePackages = "com.example.repository.primary",
    entityManagerFactoryRef = "primaryEntityManagerFactory",
    transactionManagerRef = "primaryTransactionManager")
public class PrimaryJpaConfig {

    @Primary
    @Bean(name = "primaryEntityManagerFactory")
    public LocalContainerEntityManagerFactoryBean primaryEntityManagerFactory(
            EntityManagerFactoryBuilder builder,
            @Qualifier("primaryDataSource") DataSource dataSource) {
        return builder
            .dataSource(dataSource)
            .packages("com.example.entity.primary")
            .persistenceUnit("primary")
            .properties(jpaProperties())
            .build();
    }

    private Map<String, Object> jpaProperties() {
        Map<String, Object> props = new HashMap<>();
        props.put("hibernate.dialect", "org.hibernate.dialect.MySQL8Dialect");
        props.put("hibernate.hbm2ddl.auto", "update");
        return props;
    }
}

2. 从数据源 JPA 配置

java

复制

下载

@Configuration
@EnableJpaRepositories(
    basePackages = "com.example.repository.secondary",
    entityManagerFactoryRef = "secondaryEntityManagerFactory",
    transactionManagerRef = "secondaryTransactionManager")
public class SecondaryJpaConfig {

    @Bean(name = "secondaryEntityManagerFactory")
    public LocalContainerEntityManagerFactoryBean secondaryEntityManagerFactory(
            EntityManagerFactoryBuilder builder,
            @Qualifier("secondaryDataSource") DataSource dataSource) {
        return builder
            .dataSource(dataSource)
            .packages("com.example.entity.secondary")
            .persistenceUnit("secondary")
            .properties(jpaProperties())
            .build();
    }

    private Map<String, Object> jpaProperties() {
        Map<String, Object> props = new HashMap<>();
        props.put("hibernate.dialect", "org.hibernate.dialect.MySQL8Dialect");
        props.put("hibernate.hbm2ddl.auto", "update");
        return props;
    }
}

五、动态数据源配置（高级）

对于需要运行时动态切换数据源的场景：

1. 创建动态数据源类

java

复制

下载

public class DynamicDataSource extends AbstractRoutingDataSource {

    @Override
    protected Object determineCurrentLookupKey() {
        return DataSourceContextHolder.getDataSourceType();
    }
}

2. 数据源上下文持有类

java

复制

下载

public class DataSourceContextHolder {
    
    private static final ThreadLocal<String> contextHolder = new ThreadLocal<>();
    
    public static void setDataSourceType(String dataSourceType) {
        contextHolder.set(dataSourceType);
    }
    
    public static String getDataSourceType() {
        return contextHolder.get();
    }
    
    public static void clearDataSourceType() {
        contextHolder.remove();
    }
}

3. 配置动态数据源

java

复制

下载

@Configuration
public class DynamicDataSourceConfig {

    @Bean
    @Primary
    public DataSource dynamicDataSource(
            @Qualifier("primaryDataSource") DataSource primaryDataSource,
            @Qualifier("secondaryDataSource") DataSource secondaryDataSource) {
        
        Map<Object, Object> targetDataSources = new HashMap<>();
        targetDataSources.put("primary", primaryDataSource);
        targetDataSources.put("secondary", secondaryDataSource);
        
        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        dynamicDataSource.setTargetDataSources(targetDataSources);
        dynamicDataSource.setDefaultTargetDataSource(primaryDataSource);
        
        return dynamicDataSource;
    }
}

六、监控配置

为每个数据源配置独立的监控：

java

复制

下载

@Configuration
public class DruidMonitorConfig {

    @Bean
    public ServletRegistrationBean<StatViewServlet> primaryStatViewServlet() {
        ServletRegistrationBean<StatViewServlet> bean = 
            new ServletRegistrationBean<>(new StatViewServlet(), "/druid/primary/*");
        bean.addInitParameter("loginUsername", "admin");
        bean.addInitParameter("loginPassword", "123456");
        return bean;
    }

    @Bean
    public ServletRegistrationBean<StatViewServlet> secondaryStatViewServlet() {
        ServletRegistrationBean<StatViewServlet> bean = 
            new ServletRegistrationBean<>(new StatViewServlet(), "/druid/secondary/*");
        bean.addInitParameter("loginUsername", "admin");
        bean.addInitParameter("loginPassword", "123456");
        return bean;
    }
}

七、最佳实践建议

1. 命名规范：

   • 为每个数据源使用清晰的命名（如 primary/secondary）

   • 包结构按数据源分离（mapper.primary, mapper.secondary）

2. 事务管理：

   • 避免跨数据源事务

   • 如需分布式事务考虑使用Seata等框架

3. 性能优化：

   • 根据业务负载调整各数据源的连接池参数

   • 监控各数据源的使用情况

4. 安全考虑：

   • 为监控页面设置强密码

   • 生产环境禁用DDL自动更新（hibernate.hbm2ddl.auto）

通过以上配置，可以在Spring Boot应用中灵活使用多个Druid数据源，并根据业务需求选择最适合的配置方式。