我在我的DAOImpl文件中使用sessionFactory自动装配它。
在我开始面对某些DAO方法中的＆＃34;太多的数据库连接＆＃34; 问题之前，情况一直很好。在搜索了可能的原因和解决方案后，我意识到我可能错误地配置了applicationContext.xml和我使用EntityManager的方式不正确。
以下是我的 applicationContext.xml 文件内容：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx" xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">
<!-- Enables the Spring MVC @Controller programming model -->
<!-- enables cors (cross origin request) for all urls -->
<mvc:cors>
<mvc:mapping path="/**" />
</mvc:cors>
<!-- <mvc:annotation-driven /> -->
<mvc:annotation-driven>
<mvc:message-converters>
<!-- Use the HibernateAware mapper instead of the default -->
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="objectMapper">
<bean class="com.typjaipur.core.objectmapper.HibernateAwareObjectMapper" />
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
<context:component-scan base-package="com.typjaipur" />
<bean id="messageSource"
class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
<property name="basename" value="classpath:messages" />
<property name="defaultEncoding" value="UTF-8" />
</bean>
<bean id="propertyPlaceholder" class="com.typjaipur.core.config.EnvironmentPropertyPlaceholderConfigurer">
<property name="locations">
<list>
<value>classpath:jdbc.properties</value>
<value>classpath:core.properties</value>
<value>classpath:mailer.properties</value>
</list>
</property>
</bean>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
</bean>
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="${driver}" />
<property name="url" value="${url}" />
<property name="username" value="${username}" />
<property name="password" value="${password}" />
</bean>
<bean id="sessionFactory"
class="org.springframework.orm.hibernate5.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="packagesToScan" value="com.typjaipur.model" />
<property name="hibernateProperties">
<props>
<prop key="hibernate.max_fetch_depth">3</prop>
<prop key="hibernate.default_batch_fetch_size">4</prop>
<prop key="hibernate.jdbc.fetch_size">50</prop>
<prop key="hibernate.jdbc.batch_size">20</prop>
<prop key="hibernate.dialect">${hibernate.dialect}</prop>
<prop key="hibernate.show_sql">${hibernate.show_sql}</prop>
<prop key="hibernate.format_sql">${hibernate.format_sql}</prop>
</props>
</property>
</bean>
<bean id="hibernateTransactionManager"
class="org.springframework.orm.hibernate5.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
<tx:annotation-driven transaction-manager="hibernateTransactionManager" />
<mvc:interceptors>
<bean class="org.springframework.orm.hibernate5.support.OpenSessionInViewInterceptor">
<property name="sessionFactory">
<ref bean="sessionFactory" />
</property>
</bean>
<mvc:interceptor>
<mvc:mapping path="/**" />
<!-- excluded urls -->
<mvc:exclude-mapping path="/" />
<bean class="com.typjaipur.interceptor.ApiAuthenticationInterceptor" />
</mvc:interceptor>
</mvc:interceptors>
<!-- Enables swgger ui -->
<mvc:resources mapping="swagger-ui.html" location="classpath:/META-INF/resources/" />
<mvc:resources mapping="/webjars/**"
location="classpath:/META-INF/resources/webjars/" />
<!-- Include a swagger configuration -->
<bean name="/applicationSwaggerConfig" class="com.typjaipur.config.SwaggerConfig" />
<bean id="multipartResolver"
class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!-- one of the properties available; the maximum file size in bytes -->
<!-- <property name="maxUploadSize" value="100000"/> -->
</bean>
</beans>
以下是关于我如何使用EntityManager的DAOImpl代码示例，但是我觉得它不正确。
@Repository
public class BusinessDetailsDAOImpl extends BaseDAOImpl<BusinessDetails, Long> implements BusinessDetailsDAO {
@Autowired
private SessionFactory sessionFactory;
@Override
public List<BusinessDetails> searchBusiness(BusinessSearchDTO businessSearchDTO, List<Long> businessIds) {
EntityManager entityManager = sessionFactory.getCurrentSession().getEntityManagerFactory().createEntityManager();
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
CriteriaQuery<BusinessDetails> query = criteriaBuilder.createQuery(BusinessDetails.class);
Root<BusinessDetails> businessDetails = query.from(BusinessDetails.class);
List<Predicate> predicates = new ArrayList<Predicate>();
...//rest of code
此时我很难避免sessionFactory ，因为我已经在我的项目中使用了它。无论如何我可以配置我的xml文件以允许我一起使用EntityManager以及SessionFactory吗？
我看到了几个配置EntityManager的示例，但没有一个在SessionFactory的xml文件中添加任何行。所以我对此很困惑。
答案 0 :(得分：0)
使用LocalContainerEntityManagerFactoryBean创建EntityManager而不是使用LocalSessionFactoryBean，因此您没有致电sessionFactory.getCurrentSession().getEntityManagerFactory().createEntityManager()来获取entityManager：
<!-- Create a datasource -->
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="${driver}" />
<property name="url" value="${url}" />
<property name="username" value="${username}" />
<property name="password" value="${password}" />
</bean>
<!-- Create an Hibernate to Jpa adapter -->
<bean id="jpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="generateDdl" value="true" />
<property name="showSql" value="false" />
<property name="database" value="MYSQL" />
</bean>
<!-- persistenceUnitManager is optional -->
<bean id="persistenceUnitManager" class="org.springframework.orm.jpa.persistenceunit.DefaultPersistenceUnitManager">
<property name="defaultDataSource" ref="dataSource"/>
</bean>
<!-- create entityManagerFactory -->
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="persistenceUnitManager" ref="persistenceUnitManager"/>
<property name="jpaVendorAdapter" ref="jpaVendorAdapter" />
<property name="jpaProperties">
<props>
<prop key="hibernate.temp.use_jdbc_metadata_defaults">false</prop>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
</props>
</property>
</bean>
<!-- and create transactionManager -->
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>
@Repository
public class BusinessDetailsDAOImpl extends BaseDAOImpl<BusinessDetails, Long> implements BusinessDetailsDAO {
@PersistenceContext
protected EntityManager entityManager;
@Override
public List<BusinessDetails> searchBusiness(BusinessSearchDTO businessSearchDTO, List<Long> businessIds) {
// use directly entityManager instead of sessionFactory.getCurrentSession().getEntityManagerFactory().createEntityManager();
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
// ...
}
修改：按以下步骤更新您的配置：
<property name="jpaProperties">
<props>
<prop key="hibernate.temp.use_jdbc_metadata_defaults">false</prop>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
<!-- add this line -->
<prop key="hibernate.enable_lazy_load_no_trans">true</prop>
</props>
</property>