Spring data Jpa Entity not managed Exception when calling refresh

Question

I have a db code jar which I use in different application for accessing db. I am using spring data jpa. I need to call refresh to check for change in row in db from some other application. Here How I implement it. My StudentRepository interface:

public interface StudentRepository extends JpaRepository<StudentEntity, Integer>, StudentRepositoryCustom {}

My StudentRespositoryCustom interface

public interface StudentRepositoryCustom {
    void detach(StudentEntity studentEntity);
    void refresh(StudentEntity studentEntity);}

My StudentRepositoryCustomImpl class

public class StudentRepositoryImpl implements StudentRepositoryCustom {

@PersistenceContext
EntityManager entityManager;

@Override
@Transactional
public void detach(StudentEntity studentEntity) {
    entityManager.detach(studentEntity);
}

@Override
@Transactional
public void refresh(StudentEntity studentEntity) {
    entityManager.refresh(studentEntity);
}}

My Test

@Test
public void refreshTest(){
    StudentEntity studentEntity = studentRepository.findOne(6);
    studentRepository.refresh(studentEntity);
}

But it throws this exception:

org.springframework.dao.InvalidDataAccessApiUsageException: Entity not managed; nested exception is java.lang.IllegalArgumentException: Entity not managed

at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:384)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:492)
at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:59)

This line in hibernate-core-5.2.1.final SessionImpl class return null

EntityEntry entry = persistenceContext.getEntry( object );

It should return entity I think.

My persistence.xml file is

<persistence-unit name="testPersitanceUnit" transaction-type="RESOURCE_LOCAL">
    <provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
    <class>com.sample.dao.gen.StudentEntity</class>
    <properties>
        <property name="hibernate.archive.autodetection" value="class"/>
        <property name="hibernate.show_sql" value="true"/>
        <property name="hibernate.format_sql" value="true"/>
        <property name="hbm2ddl.auto" value="update"/>
        <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect" />
        <property name="hibernate.enable_lazy_load_no_trans" value="true" />
    </properties>
</persistence-unit>

My spring db config file is

 <jpa:repositories base-package="com.sample.dao.repos"
                  entity-manager-factory-ref="entityManagerFactory" transaction-manager-ref="transactionManager"/>

<!-- Enable the component scan (auto wiring etc) for the following package -->
<context:component-scan base-package="com.sample.dao" />

<!-- Make sure the following is specified to enable transaction  -->
<tx:annotation-driven />
<bean class="org.springframework.orm.jpa.JpaTransactionManager" id="transactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>

<!--  This defines the entity manager factory with some custom properties -->
<bean id='entityManagerFactory' primary="true" class='org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean'>
    <property name="persistenceUnitName" value="testPersitanceUnit"/>
    <property name='dataSource' ref='dataSource' />
    <property name="packagesToScan" value="com.sample.dao" />
enter code here

Answer 1

尝试在刷新之前使用合并。

public void refresh(T entity) {
        this.entityManager.refresh(this.entityManager.merge(entity));

  }

Answer 2

尝试

public StudentEntity refresh(StudentEntity studentEntity) {
    StudentEntity managedEntity = entityManager.find(StudentEntity.class, studentEntity.getId());
    entityManager.refresh(managedEntity);
    return managedEntity;
}}

您遇到问题的原因是在您的测试中，您的 studentEntity 在事务 (findOne) 之外传递，因此不再管理。当它被传递到一个新事务（刷新）时，它不受管理，因此会引发此错误。

或者，如果原始刷新是所需的行为，您可以将整个测试包装在一个事务中，这应该维护您的测试对象的管理。

Answer 3

其实这是一个查询问题。查询生成内部联接，因此返回空列表，因此引发异常。我更改了映射，以便它可以生成外连接，然后返回一行，并且成功了。