【精·超详细】SpringBoot 配置多个数据源（连接多个数据库）

在Spring Boot中配置多个数据源通常涉及以下步骤：

1. 配置数据源属性。
2. 创建数据源实例。
3. 配置EntityManagerFactory和TransactionManager。
4. 配置@Configuration类来扫描相应的包以使用正确的实体。

以下是一个配置两个数据源的示例代码：

@Configuration
public class DataSourceConfig {
 
    @Bean
    @Primary
    @ConfigurationProperties(prefix = "spring.datasource.primary")
    public DataSource primaryDataSource() {
        return DataSourceBuilder.create().build();
    }
 
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource.secondary")
    public DataSource secondaryDataSource() {
        return DataSourceBuilder.create().build();
    }
 
    @Bean
    public LocalContainerEntityManagerFactoryBean primaryEntityManagerFactory(
            EntityManagerFactoryBuilder builder) {
        return builder
                .dataSource(primaryDataSource())
                .packages("com.yourpackage.model.primary")
                .persistenceUnit("primary")
                .build();
    }
 
    @Bean
    public LocalContainerEntityManagerFactoryBean secondaryEntityManagerFactory(
            EntityManagerFactoryBuilder builder) {
        return builder
                .dataSource(secondaryDataSource())
                .packages("com.yourpackage.model.secondary")
                .persistenceUnit("secondary")
                .build();
    }
 
    @Bean
    public PlatformTransactionManager primaryTransactionManager(
            @Qualifier("primaryEntityManagerFactory") EntityManagerFactory entityManagerFactory) {
        return new JpaTransactionManager(entityManagerFactory);
    }
 
    @Bean
    public PlatformTransactionManager secondaryTransactionManager(
            @Qualifier("secondaryEntityManagerFactory") EntityManagerFactory entityManagerFactory) {
        return new JpaTransactionManager(entityManagerFactory);
    }
}

在application.properties或application.yml中配置数据源：

spring.datasource.primary.url=jdbc:mysql://localhost:3306/db_primary
spring.datasource.primary.username=user_primary
spring.datasource.primary.password=pass_primary
 
spring.datasource.secondary.url=jdbc:mysql://localhost:3306/db_secondary
spring.datasource.secondary.username=user_secondary
spring.datasource.secondary.password=pass_secondary

确保为每个数据源创建不同的包路