一、项目依赖
首先，我们需要在pom.xml中添加Spring Boot、Spring Data JPA以及数据库驱动的依赖。
<dependencies> <!-- Spring Boot Starter Data JPA --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <!-- H2 Database --> <dependency> <groupId>com.h2database</groupId> <artifactId>h2</artifactId> </dependency> <!-- MySQL Database --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> </dependencies>
二、配置多数据源
我们将配置两个数据源：一个用于H2数据库，另一个用于MySQL数据库。
1. 配置文件
在application.yml中配置数据源信息。
spring: datasource: h2: url: jdbc:h2:mem:testdb driver-class-name: org.h2.Driver username: sa password: password mysql: url: jdbc:mysql://localhost:3306/testdb driver-class-name: com.mysql.cj.jdbc.Driver username: root password: password jpa: hibernate: ddl-auto: update show-sql: true properties: hibernate: dialect: org.hibernate.dialect.H2Dialect format_sql: true
2. 数据源配置类
我们需要为每个数据源创建单独的配置类。
package cn.juwatech.config; import org.springframework.beans.factory.annotation.Qualifier; import org.springframework.boot.context.properties.ConfigurationProperties; import org.springframework.boot.jdbc.DataSourceBuilder; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.context.annotation.Primary; import org.springframework.data.jpa.repository.config.EnableJpaRepositories; import org.springframework.orm.jpa.JpaTransactionManager; import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean; import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter; import org.springframework.transaction.PlatformTransactionManager; import org.springframework.transaction.annotation.EnableTransactionManagement; import javax.persistence.EntityManagerFactory; import javax.sql.DataSource; @Configuration @EnableTransactionManagement public class DataSourceConfig { @Primary @Bean(name = "h2DataSource") @ConfigurationProperties(prefix = "spring.datasource.h2") public DataSource h2DataSource() { return DataSourceBuilder.create().build(); } @Bean(name = "mysqlDataSource") @ConfigurationProperties(prefix = "spring.datasource.mysql") public DataSource mysqlDataSource() { return DataSourceBuilder.create().build(); } @Primary @Bean(name = "h2EntityManagerFactory") public LocalContainerEntityManagerFactoryBean h2EntityManagerFactory(@Qualifier("h2DataSource") DataSource dataSource) { LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean(); em.setDataSource(dataSource); em.setPackagesToScan("cn.juwatech.model.h2"); em.setJpaVendorAdapter(new HibernateJpaVendorAdapter()); em.setPersistenceUnitName("h2PU"); return em; } @Bean(name = "mysqlEntityManagerFactory") public LocalContainerEntityManagerFactoryBean mysqlEntityManagerFactory(@Qualifier("mysqlDataSource") DataSource dataSource) { LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean(); em.setDataSource(dataSource); em.setPackagesToScan("cn.juwatech.model.mysql"); em.setJpaVendorAdapter(new HibernateJpaVendorAdapter()); em.setPersistenceUnitName("mysqlPU"); return em; } @Primary @Bean(name = "h2TransactionManager") public PlatformTransactionManager h2TransactionManager(@Qualifier("h2EntityManagerFactory") EntityManagerFactory entityManagerFactory) { return new JpaTransactionManager(entityManagerFactory); } @Bean(name = "mysqlTransactionManager") public PlatformTransactionManager mysqlTransactionManager(@Qualifier("mysqlEntityManagerFactory") EntityManagerFactory entityManagerFactory) { return new JpaTransactionManager(entityManagerFactory); } }
3. 启用JPA仓库
为每个数据源分别配置JPA仓库。
package cn.juwatech.config; import org.springframework.boot.autoconfigure.domain.EntityScan; import org.springframework.context.annotation.Configuration; import org.springframework.data.jpa.repository.config.EnableJpaRepositories; @Configuration @EnableJpaRepositories( basePackages = "cn.juwatech.repository.h2", entityManagerFactoryRef = "h2EntityManagerFactory", transactionManagerRef = "h2TransactionManager" ) @EntityScan(basePackages = "cn.juwatech.model.h2") public class H2DataSourceConfig { } @Configuration @EnableJpaRepositories( basePackages = "cn.juwatech.repository.mysql", entityManagerFactoryRef = "mysqlEntityManagerFactory", transactionManagerRef = "mysqlTransactionManager" ) @EntityScan(basePackages = "cn.juwatech.model.mysql") public class MysqlDataSourceConfig { }
三、定义实体类
在不同的包中定义不同数据源的实体类。
package cn.juwatech.model.h2; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; @Entity public class H2Entity { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; private String name; // getters and setters }
package cn.juwatech.model.mysql; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; @Entity public class MysqlEntity { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; private String name; // getters and setters }
四、定义仓库接口
为每个数据源定义对应的仓库接口。
package cn.juwatech.repository.h2; import cn.juwatech.model.h2.H2Entity; import org.springframework.data.jpa.repository.JpaRepository; public interface H2EntityRepository extends JpaRepository<H2Entity, Long> { }
package cn.juwatech.repository.mysql; import cn.juwatech.model.mysql.MysqlEntity; import org.springframework.data.jpa.repository.JpaRepository; public interface MysqlEntityRepository extends JpaRepository<MysqlEntity, Long> { }
五、测试多数据源配置
最后，我们编写一个测试类，验证多数据源配置是否成功。
package cn.juwatech; import cn.juwatech.model.h2.H2Entity; import cn.juwatech.model.mysql.MysqlEntity; import cn.juwatech.repository.h2.H2EntityRepository; import cn.juwatech.repository.mysql.MysqlEntityRepository; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.CommandLineRunner; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class MultiDataSourceApplication implements CommandLineRunner { @Autowired private H2EntityRepository h2EntityRepository; @Autowired private MysqlEntityRepository mysqlEntityRepository; public static void main(String[] args) { SpringApplication.run(MultiDataSourceApplication.class, args); } @Override public void run(String... args) throws Exception { H2Entity h2Entity = new H2Entity(); h2Entity.setName("H2 Entity"); h2EntityRepository.save(h2Entity); MysqlEntity mysqlEntity = new MysqlEntity(); mysqlEntity.setName("MySQL Entity"); mysqlEntityRepository.save(mysqlEntity); System.out.println("H2 Entities: " + h2EntityRepository.findAll()); System.out.println("MySQL Entities: " + mysqlEntityRepository.findAll()); } }
总结
通过本文的介绍，我们展示了如何在Spring Data中配置和使用多个数据源。我们首先配置了数据源，然后为每个数据源创建了单独的配置类和JPA仓库，最后验证了多数据源配置的正确性。这个示例展示了Spring Boot在处理多数据源时的灵活性和强大功能，希望对大家有所帮助。
