为了让spring知道DataSource与Repository的关系，你应该在@EnableJpaRepositories注解中定义它。假设我们有两个实体，Servers 实体和Domains 实体，每个实体都有自己的 Repo，然后每个 Repository 都有自己的 JpaDataSource 配置。
1.根据与它们相关的数据源对所有存储库进行分组。例如
Domains 实体的存储库（包：org.springdemo.multiple.datasources.repository.domains）：
package org.springdemo.multiple.datasources.repository.domains;
import org.springdemo.multiple.datasources.domain.domains.Domains;
import org.springframework.data.jpa.repository.JpaRepository;
public interface DomainsRepository extends JpaRepository<Domains,Long> {
}
Servers 实体的存储库（包：org.springdemo.multiple.datasources.repository.servers）
package org.springdemo.multiple.datasources.repository.servers;
import org.springdemo.multiple.datasources.domain.servers.Servers;
import org.springframework.data.jpa.repository.JpaRepository;
public interface ServersRepository extends JpaRepository<Servers,Long> {
}
2。您需要为每个 JPA 数据源定义一个配置，在此示例中，我将展示如何配置两个不同的数据源
Domains Jpa 配置：数据源和存储库之间的关系在basePackages 值中定义，这就是为什么需要根据每个存储库将要使用的实体管理器将存储库分组到不同包中的原因采用。
@Configuration
@EnableJpaRepositories(
entityManagerFactoryRef = "domainsEntityManager",
transactionManagerRef = "domainsTransactionManager",
basePackages = {"org.springdemo.multiple.datasources.repository.domains"}
)
public class DomainsConfig {
Servers 数据源配置：如您所见，basePackages 值具有Servers Repository 的包名称，并且entityManagerFactoryRef 和transactionManagerRef 的值也不同，以便让spring 分离每个entityManager .
@Configuration
@EnableJpaRepositories(
entityManagerFactoryRef = "serversEntityManager",
transactionManagerRef = "serversTransactionManager",
basePackages = {"org.springdemo.multiple.datasources.repository.servers"}
)
public class ServersConfig {
3.将一个数据源设置为主
为了避免错误消息：Parameter 0 of constructor in org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration required a single bean, but 2 were found: 只需将其中一个数据源设置为 @Primary，在此示例中，我选择 Servers 数据源作为主要数据源：
@Bean("serversDataSourceProperties")
@Primary
@ConfigurationProperties("app.datasource.servers")
public DataSourceProperties serversDataSourceProperties(){
return new DataSourceProperties();
}
@Bean("serversDataSource")
@Primary
@ConfigurationProperties("app.datasource.servers")
public DataSource serversDataSource(@Qualifier("serversDataSourceProperties") DataSourceProperties serversDataSourceProperties) {
return serversDataSourceProperties().initializeDataSourceBuilder().build();
}
如果您需要更多信息，请查看每个配置的完整示例：
ServersJPA 配置
@Configuration
@EnableJpaRepositories(
entityManagerFactoryRef = "serversEntityManager",
transactionManagerRef = "serversTransactionManager",
basePackages = {"org.springdemo.multiple.datasources.repository.servers"}
)
public class ServersConfig {
@Bean(name = "serversEntityManager")
public LocalContainerEntityManagerFactoryBean getServersEntityManager(EntityManagerFactoryBuilder builder,
@Qualifier("serversDataSource") DataSource serversDataSource){
return builder
.dataSource(serversDataSource)
.packages("org.springdemo.multiple.datasources.domain.servers")
.persistenceUnit("servers")
.properties(additionalJpaProperties())
.build();
}
Map<String,?> additionalJpaProperties(){
Map<String,String> map = new HashMap<>();
map.put("hibernate.hbm2ddl.auto", "create");
map.put("hibernate.dialect", "org.hibernate.dialect.MySQLDialect");
map.put("hibernate.show_sql", "true");
return map;
}
@Bean("serversDataSourceProperties")
@Primary
@ConfigurationProperties("app.datasource.servers")
public DataSourceProperties serversDataSourceProperties(){
return new DataSourceProperties();
}
@Bean("serversDataSource")
@Primary
@ConfigurationProperties("app.datasource.servers")
public DataSource serversDataSource(@Qualifier("serversDataSourceProperties") DataSourceProperties serversDataSourceProperties) {
return serversDataSourceProperties().initializeDataSourceBuilder().build();
}
@Bean(name = "serversTransactionManager")
public JpaTransactionManager transactionManager(@Qualifier("serversEntityManager") EntityManagerFactory serversEntityManager){
JpaTransactionManager transactionManager = new JpaTransactionManager();
transactionManager.setEntityManagerFactory(serversEntityManager);
return transactionManager;
}
}
DomainsJPA 配置
@Configuration
@EnableJpaRepositories(
entityManagerFactoryRef = "domainsEntityManager",
transactionManagerRef = "domainsTransactionManager",
basePackages = {"org.springdemo.multiple.datasources.repository.domains"}
)
public class DomainsConfig {
@Bean(name = "domainsEntityManager")
public LocalContainerEntityManagerFactoryBean getdomainsEntityManager(EntityManagerFactoryBuilder builder
,@Qualifier("domainsDataSource") DataSource domainsDataSource){
return builder
.dataSource(domainsDataSource)
.packages("org.springdemo.multiple.datasources.domain.domains")
.persistenceUnit("domains")
.properties(additionalJpaProperties())
.build();
}
Map<String,?> additionalJpaProperties(){
Map<String,String> map = new HashMap<>();
map.put("hibernate.hbm2ddl.auto", "create");
map.put("hibernate.dialect", "org.hibernate.dialect.H2Dialect");
map.put("hibernate.show_sql", "true");
return map;
}
@Bean("domainsDataSourceProperties")
@ConfigurationProperties("app.datasource.domains")
public DataSourceProperties domainsDataSourceProperties(){
return new DataSourceProperties();
}
@Bean("domainsDataSource")
public DataSource domainsDataSource(@Qualifier("domainsDataSourceProperties") DataSourceProperties domainsDataSourceProperties) {
return domainsDataSourceProperties.initializeDataSourceBuilder().build();
}
@Bean(name = "domainsTransactionManager")
public JpaTransactionManager transactionManager(@Qualifier("domainsEntityManager") EntityManagerFactory domainsEntityManager){
JpaTransactionManager transactionManager = new JpaTransactionManager();
transactionManager.setEntityManagerFactory(domainsEntityManager);
return transactionManager;
}
}
为了分离每个数据源，我将配置放在application.properties 文件中，如下所示：
app.datasource.domains.url=jdbc:h2:mem:~/test
app.datasource.domains.driver-class-name=org.h2.Driver
app.datasource.servers.driver-class-name=com.mysql.jdbc.Driver
app.datasource.servers.url=jdbc:mysql://localhost:3306/v?autoReconnect=true&useSSL=false
app.datasource.servers.username=myuser
app.datasource.servers.password=mypass
如果您需要更多信息，请参阅以下文档：
Spring Documentation: howto-two-datasources
如何配置两个不同数据库的类似示例：github example