SpringBoot操作多数据源（JPA+JdbcTemplate）

本文仅对如何在Springboot中使用Spring Data JPA和JdbcTemplate去操作多个HikariCP数据源进行简单示例和介绍，项目的完整目录层次如下图所示。

添加依赖与配置

为了使用Spring Data JPA和HikariCP数据源，需要在工程POM文件中引入它们的Maven依赖。

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.4.1.RELEASE</version>
	</parent>
	<dependencies>
		<!-- 添加MySQL依赖 -->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
		</dependency>
		<!-- 添加JDBC依赖 -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-jpa</artifactId>
			<exclusions>
				<!-- 排除Tomcat-JDBC依赖 -->
				<exclusion>
					<groupId>org.apache.tomcat</groupId>
					<artifactId>tomcat-jdbc</artifactId>
				</exclusion>
			</exclusions>
		</dependency>
		<!-- 添加HikariCP依赖 -->
		<dependency>
			<groupId>com.zaxxer</groupId>
			<artifactId>HikariCP</artifactId>
		</dependency>
	</dependencies>

在application.properties核心配置文件中除了要定义MYSQL数据库连接信息外，还需要添加如下JPA相关配置。

#########################################################
### Primary DataSource -- DataSource 1 configuration  ###
#########################################################
primary.datasource.jdbc-url=jdbc:mysql://localhost:3306/dev1?useUnicode=true&characterEncoding=utf8
primary.datasource.driverClassName=com.mysql.jdbc.Driver
primary.datasource.username=root
primary.datasource.password=123456

#########################################################
### Secondary DataSource -- DataSource 2 configuration ##
#########################################################
secondary.datasource.url=jdbc:mysql://localhost:3306/dev2?useUnicode=true&characterEncoding=utf8
secondary.datasource.driverClassName=com.mysql.jdbc.Driver
secondary.datasource.username=root
secondary.datasource.password=123456
secondary.datasource.type=com.zaxxer.hikari.HikariDataSource

#########################################################
### Java Persistence Api --  Spring jpa configuration ###
#########################################################
# Specify the DBMS
spring.jpa.database = MYSQL
# Show or not log for each sql query
spring.jpa.show-sql = true
# Hibernate ddl auto (create, create-drop, update)
spring.jpa.hibernate.ddl-auto = update
# Naming strategy
#[org.hibernate.cfg.ImprovedNamingStrategy  #org.hibernate.cfg.DefaultNamingStrategy]
spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy
# stripped before adding them to the entity manager)
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect

配置数据源与JdbcTemplate

首先，在DataSourceConfig配置类中定义两个数据源，同时为每一个数据源创建一个JdbcTemplate。

@Configuration
public class DataSourceConfig {

	/**
	 * 数据源 1
	 */
	@Primary
	@Bean(name = "primaryDataSource")
	@ConfigurationProperties(prefix = "primary.datasource")
	public DataSource primaryDataSource() {
		return DataSourceBuilder.create().build();
	}

	@Primary
	@Bean(name = "secondaryDataSourceProperties")
	@ConfigurationProperties(prefix = "secondary.datasource")
	public DataSourceProperties secondaryDataSourceProperties() {
		return new DataSourceProperties();
	}

	/**
	 * 数据源 2
	 */
	@Bean(name = "secondaryDataSource")
	public DataSource thirdDataSource(
			@Qualifier("secondaryDataSourceProperties") DataSourceProperties dataSourceProperties) {
		return dataSourceProperties.initializeDataSourceBuilder().build();
	}

	/**
	 * 数据源 1 的 JdbcTemplate
	 */
	@Bean(name = "primaryJdbcTemplate")
	public JdbcTemplate primaryJdbcTemplate(@Qualifier("primaryDataSource") DataSource dataSource) {
		return new JdbcTemplate(dataSource);
	}

	/**
	 * 数据源 2  的 JdbcTemplate
	 */
	@Bean(name = "secondaryJdbcTemplate")
	public JdbcTemplate secondaryJdbcTemplate(@Qualifier("secondaryDataSource") DataSource dataSource) {
		return new JdbcTemplate(dataSource);
	}
}

使用JdbcTemplate操作数据源

在Dao层中通过注入不同的JdbcTemplate来操作对应的数据源。

/**
 * 使用 JdbcTemplate 操作数据源 1 
 */
@Repository
public class UserDao {

	@Autowired
	@Qualifier("primaryJdbcTemplate")
	private JdbcTemplate jdbcTemplate;

	@Transactional
	public void addUser(Integer userAge, String userName) {
		String sql = "insert into tbl_user (age,name) values ('" + userAge + "','" + userName + "');";
		jdbcTemplate.execute(sql);
	}
}

/**
 * 使用 JdbcTemplate 操作数据源 2
 */
@Repository
public class DepartmentDao {

	@Autowired
	@Qualifier("secondaryJdbcTemplate")
	private JdbcTemplate jdbcTemplate;

	@Transactional
	public void addDept(String userName) {
		String sql = "insert into tbl_dept (name) values ('" + userName + "');";
		jdbcTemplate.execute(sql);
	}
}

配置JPA

通过注解@EnableJpaRepositories来为不同包下的Repository分别创建不同TransactionManager和EntityManagerFactory，用来操作不同的数据源。

/**
 * 数据源 1 JPA配置
 */
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(entityManagerFactoryRef = "primaryEntityManagerFactory", transactionManagerRef = "primaryTransactionManager", basePackages = {
		"com.pengjunlee.primary.repository" }) // 设置Repository所在位置
public class PrimaryConfig {

	@Autowired
	@Qualifier("primaryDataSource")
	private DataSource primaryDataSource;

	@Autowired
	private JpaProperties jpaProperties;

	@Primary
	@Bean(name = "primaryEntityManager")
	public EntityManager entityManager(EntityManagerFactoryBuilder builder) {
		return primaryEntityManagerFactory(builder).getObject().createEntityManager();
	}

	@Primary
	@Bean(name = "primaryEntityManagerFactory")
	public LocalContainerEntityManagerFactoryBean primaryEntityManagerFactory(EntityManagerFactoryBuilder builder) {
		return builder.dataSource(primaryDataSource).properties(getVendorProperties(primaryDataSource))
				.packages("com.pengjunlee.primary.entity") // 设置实体类所在位置
				.persistenceUnit("primaryPersistenceUnit").build();
	}

	private Map<String, String> getVendorProperties(DataSource dataSource) {
		return jpaProperties.getHibernateProperties(dataSource);
	}

	@Primary
	@Bean(name = "primaryTransactionManager")
	public PlatformTransactionManager primaryTransactionManager(EntityManagerFactoryBuilder builder) {
		return new JpaTransactionManager(primaryEntityManagerFactory(builder).getObject());
	}
}

/**
 * 数据源 2 JPA配置
 */
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(entityManagerFactoryRef = "secondaryEntityManagerFactory", transactionManagerRef = "secondaryTransactionManager", basePackages = {
		"com.pengjunlee.secondary.repository" }) // 设置Repository所在位置
public class SecondaryConfig {

	@Autowired
	@Qualifier("secondaryDataSource")
	private DataSource secondaryDataSource;

	@Autowired
	private JpaProperties jpaProperties;

	@Bean(name = "secondaryEntityManager")
	public EntityManager entityManager(EntityManagerFactoryBuilder builder) {
		return secondaryEntityManagerFactory(builder).getObject().createEntityManager();
	}

	@Bean(name = "secondaryEntityManagerFactory")
	public LocalContainerEntityManagerFactoryBean secondaryEntityManagerFactory(EntityManagerFactoryBuilder builder) {
		return builder.dataSource(secondaryDataSource).properties(getVendorProperties(secondaryDataSource))
				.packages("com.pengjunlee.secondary.entity") // 设置实体类所在位置
				.persistenceUnit("secondaryPersistenceUnit").build();
	}

	private Map<String, String> getVendorProperties(DataSource dataSource) {
		return jpaProperties.getHibernateProperties(dataSource);
	}

	@Bean(name = "secondaryTransactionManager")
	public PlatformTransactionManager secondaryTransactionManager(EntityManagerFactoryBuilder builder) {
		return new JpaTransactionManager(secondaryEntityManagerFactory(builder).getObject());
	}
}

使用JPA操作数据源

由于是通过包名来区分哪些Repository用来操作哪个数据源，故而需要将不同数据源的Entity和Repository类放入不同的包中。
此处定义了User（用户）和Department（部门）两个实体类，分别对应数据源一和数据源二。

@Entity
@Table(name = "tbl_user")
public class User {

	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	private Long id;

	private String name;

	private Integer age;

	// 此处省略get和set方法

}

@Entity
@Table(name = "tbl_dept")
public class Department {

	@Id
	@GeneratedValue(strategy = GenerationType.IDENTITY)
	private Long id;

	private String name;

	// 此处省略get和set方法

}

/**
 * 使用 JPA 操作数据源 1 
 */
@Repository
public interface UserRepository extends CrudRepository<User, Long> {

}

/**
 * 使用 JPA 操作数据源 2
 */
@Repository
public interface DepartmentRepository extends CrudRepository<Department, Long> {

}

启动类中测试

在启动类中进行数据源测试，并分别向两个数据库中添加记录。

@SpringBootApplication
@EnableTransactionManagement // 只会回滚运行期异常
public class MyApplication {

	public static void main(String[] args) throws SQLException {
		ConfigurableApplicationContext context = SpringApplication.run(MyApplication.class, args);

		Object ds1 = context.getBean("primaryDataSource");
		System.out.println(ds1.getClass().getName());

		Object ds2 = context.getBean("secondaryDataSource");
		System.out.println(ds2.getClass().getName());

		UserRepository userRepository = context.getBean(UserRepository.class);
		User user1 = new User();
		user1.setAge(21);
		user1.setName("Tracy");
		userRepository.save(user1);

		DepartmentRepository deptRepository = context.getBean(DepartmentRepository.class);
		Department dept1 = new Department();
		dept1.setName("集团事业部");
		deptRepository.save(dept1);

		UserDao userDao = context.getBean(UserDao.class);
		userDao.addUser(30, "pengjunlee");

		DepartmentDao deptDao = context.getBean(DepartmentDao.class);
		deptDao.addDept("总裁办公室");
	}
}

启动程序，两个数据库中的用户表和部门表中数据都能正常添加成功。
在实际项目中我们一般都会将定义好的Repository自动装配到Service层进行调用，此时要格外注意事务。

@Service
@Transactional("primaryTransactionManager")
public class UserServiceImpl implements UserService {

	@Autowired
	private UserRepository userRepository;

	public void deleteUserById(Long id) {
		userRepository.delete(id);
	}
}

本文项目源码已上传至CSDN，资源地址：https://download.csdn.net/download/pengjunlee/10382622