我的应用程序具有多个数据源，因此我基于此URL创建了两个数据源配置类。
但是在运行spring boot应用程序时出现错误
从StackOverflow上的这个Question帮助我弄清楚了这个问题。我需要在我的JPA存储库上指定entityManagerFactoryRef。
但是我有许多存储库类，其中一些使用Entitymanager'A'，而另一些使用'B'。我当前的Spring Boot应用程序类是这样的
@SpringBootApplication(exclude = { DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class,
DataSourceTransactionManagerAutoConfiguration.class })
@EnableTransactionManagement
@EntityScan("com.info.entity")
@ComponentScan({"com.info.services","com.info.restcontroller"})
@EnableJpaRepositories("com.info.repositories")
public class CavionApplication {
public static void main(String[] args) {
SpringApplication.run(CavionApplication.class, args);
}
@Bean
public CommandLineRunner commandLineRunner(ApplicationContext ctx) {
return args -> {
System.out.println("Let's inspect the beans provided by Spring Boot:");
String[] beanNames = ctx.getBeanDefinitionNames();
Arrays.sort(beanNames);
for (String beanName : beanNames) {
System.out.println(beanName);
}
};
}}
请提出设置多个数据源的最佳方法。
最佳答案
为了让spring知道什么DataSource与什么Repository相关，您应该在@EnableJpaRepositories批注中对其进行定义。假设我们有两个实体，Servers实体和Domains实体，并且每个实体都有自己的存储库，那么每个存储库都有自己的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(软件包: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(软件包: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 Data Soruce定义一个配置，在此示例中，我将说明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，这就是为什么有必要根据每个存储库将使用的实体管理器将存储库分为不同包的原因。@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存储库的包名称，并且entityManagerFactoryRef和transactionManagerRef的值也不同，以便让spring分开每个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
为了避免出现错误消息:
Parameter 0 of constructor in org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration required a single bean, but 2 were found:只是将数据源之一设置为@Primary，在本示例中，我选择Servers数据源作为主数据:@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，请参见每种配置的完整示例:
Servers JPA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;
}
}
Domains JPA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
一个类似的示例，说明如何配置两个不同的数据库:github example