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：
|
1
2
|
@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：
|
1
2
3
4
5
6
7
8
9
10
|
@Bean(name = "entityManagerFactoryPrimary")@Primarypublic 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
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
|
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")
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
|
@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服务器之家。
原文链接：https://blog.csdn.net/jim_LoveQ/article/details/107494356
