JPA EntityManager踩坑之更改PersistenceContext
一、原因
项目中配置两个Spring JPA的数据源，使用EntityManager的时候默认是选择第一个，导致查询不到第二个数据源的数据。
二、Spring JPA多数据源怎么使用EntityManager
1. Spring JPA多数据源的配置请查看此文章：SpringData JPA基本/高级/多数据源使用
2. 引入EntityManager：
@PersistenceContext(unitName = "primaryPersistenceUnit")
private EntityManager entityManager;@PersistenceContext中的unitName指的是使用哪一个数据源的persistenceUnit，persistenceUnit是在配置数据源的时候配置的，每一个数据源的persistenceUnit都是不一样的，这样就可以使用不同的数据源来查询数据了。
配置persistenceUnit：
@Bean(name = "entityManagerFactoryPrimary")
@Primary
public LocalContainerEntityManagerFactoryBean entityManagerFactoryPrimary (EntityManagerFactoryBuilder builder) {
return builder
.dataSource(primaryDataSource)
.properties(vendorProperties)
.packages("com.neo.model") //设置实体类所在位置
.persistenceUnit("primaryPersistenceUnit")
.build();
}三、使用EntityManager
String SQL = "select id ,code,name,'desc' from drgo_cd10_dx_code where name like ('%"+content.trim()+"%') "
logger.info("search getProductOwnerId SQL:"+SQL);
Query query = entityManager.createNativeQuery(SQL);
List<Object[]> dbList = query.getResultList();
List<ICD10CodeData> resultList = new ArrayList<ICD10CodeData>();
if (dbList!=null && dbList.size()>0){
for (int i =0;i<dbList.size();i++){
Object[] o = dbList.get(i);
String id = o[0]==null?"":o[0].toString();
String code = o[1]==null?"":o[1].toString();
String name = o[0]==null?"":o[2].toString();
String desc = o[1]==null?"":o[3].toString();
ICD10CodeData tempCode = new ICD10CodeData(Long.parseLong(id), code, name, desc);
resultList.add(tempCode);
}
}@PersistenceContext(unitName = "entityManagerFactory")
@Configuration
@EnableTransactionManagement(mode = AdviceMode.ASPECTJ, proxyTargetClass = true)
@ComponentScan({cn.com.appName.manager,cn.com.appName.dao,cn.com.appName.dao.jpa})
public class AppConfig extends AbstractManager
{
@Bean(name = "entityManagerFactory")
public LocalContainerEntityManagerFactoryBean entityManagerFactoryBean()
{
LocalContainerEntityManagerFactoryBean factoryBean = new LocalContainerEntityManagerFactoryBean();
factoryBean.setDataSource(dataSource(null));
factoryBean.setPackagesToScan(new String[] { "cn.com." + AppConfig.APP_NAME + ".entity" });
HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
vendorAdapter.setDatabasePlatform(hibernateDialect);
if (logger.isDebugEnabled())
{
// vendorAdapter.setShowSql(true);
// vendorAdapter.setGenerateDdl(true);
}
//vendorAdapter.setGenerateDdl(true);
factoryBean.setJpaVendorAdapter(vendorAdapter);
// factoryBean.setJpaProperties(this.additionlProperties());
return factoryBean;
}
}
public abstract class MyBaseDao<E extends BaseEntity> extends BaseDaoJpa<E>
{
protected MyBaseDao()
{ }
//unitName与LocalContainerEntityManagerFactoryBean类的容器对象的名称一致
@PersistenceContext(unitName = "entityManagerFactory")
public void setJpaEntityManager(EntityManager entityManager)
{
super.setEntityManager(entityManager);
}
}以上为个人经验，希望能给大家一个参考，也希望大家多多支持编程网。
