Question

我在SO上经历了很多类似的问题，通常答案是只将#include "myclass.h" MyClass::MyClass(QObject * parent) : QObject{parent} { connect(&timer, SIGNAL(timeout()), SLOT(on_timeout())); } void MyClass::timerStart() { timer.start(1000); } void MyClass::on_timeout() { msg.setText("updated"); msg.show(); }添加到类和方法中。但这对我不起作用，因此我假设我做错了什么？

MyRepository：

@Transactional

AbstractRepository：

@Repository
public class MyRepository extends AbstractRepository<MyEntity> implements org.springframework.data.repository.Repository<MyEntity, Long> {

    @PersistenceContext
    private EntityManager em;

    public MyRepository() {
        super(MyEnitiy.class);
    }

    @Override
    public EntityManager getEntityManager() {
        return em;
    }

    @SuppressWarnings("unchecked")
    @Transactional
    public List<MyEnitiy> getAllFor(Integer id) {        
        return getEntityManager().createQuery("SELECT k FROM MyEntity k WHERE k.otherid = :otherid ORDER BY k.something", MyEntity.class)
            .setParameter("otherid", id).getResultList();
    }
}

我的Sping网络控制器（代码段）：

@Transactional(readOnly = true)
public abstract class AbstractRepository<T> {

    ...
    @Modifying
    @Transactional
    public void edit(T entity) {
        getEntityManager().merge(entity);
    }
    ...
}

更新：

spring-database.xml（使用池试图尝试修复Tomcat内存泄漏）：

@Controller
public class MyController {
    @Autowired
    private MyRepository myRepository;

    @RequestMapping(value = {"/here/there"}, method = RequestMethod.GET)
    @ResponseBody
    @Transactional
    public String hereAndTherePage(@RequestParam(value = "id", required = true) Integer id,
            HttpServletRequest request, HttpSession session) {
        List<MyEntity> myEntities = myRepository.getAllFor(id);
        for(MyEntity myEntity : myEntities) {
            ...
            myEntity.setSomeValue(myEntity.getSomeValue() + 1);
            ...
            myRepository.edit(myEntity);

调用<bean class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory" /> </bean> <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="packagesToScan" value="com.example.*" /> <property name="jpaVendorAdapter"> <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"> <property name="database" value="MYSQL" /> <property name="generateDdl" value="true" /> </bean> </property> </bean> <bean id="poolProperties" class="org.apache.tomcat.jdbc.pool.PoolProperties"> <property name="url" value="jdbc:mysql://localhost:3306/bfwinkel?noAccessToProcedureBodies=true"/> <property name="driverClassName" value="com.mysql.jdbc.Driver"/> <property name="validationQuery" value="SELECT 1"/> <property name="testOnBorrow" value="true"/> <property name="jdbcInterceptors" value="org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer"/> <property name="maxActive" value="10"/> <property name="maxIdle" value="10"/> <property name="username" value="d[-.-]b"/> <property name="password" value="~!~"/> </bean> <bean id="dataSource" class="org.apache.tomcat.jdbc.pool.DataSource" destroy-method="close"> <property name="poolProperties" ref="poolProperties"/> </bean>时会抛出异常：

getEntityManager().merge(entity);

Answer 1

将以下行添加到spring-database.xml

<bean id="txManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory" />
    <property name="dataSource" ref="dataSource" />
    <property name="jpaDialect" ref="jpaDialect" />
</bean>

<tx:annotation-driven transaction-manager="txManager" />

Answer 2

此错误意味着，当您尝试合并实体时，它们没有可用的持久性上下文。

您有三个选项可以按优先级解决此问题。

1-您是否已将@EnableTransactionManagement添加到您的配置中？

2-如果你有一个persistence.xml文件，你应该为@PersistenceContext添加一个unitname属性。

3-使用扩展持久性上下文而不是事务范围的持久性上下文。

我希望我的回答会对你有帮助。

祝你好运

Spring Web App + JPA没有可用的事务性EntityManager

2 个答案: