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我有實體的這個例子：如何使用CrudRepository從數據庫中獲取'現在時間'？
@Entity
public class User {
private String name;
private Date creationDate;
public User(String name) {
this.name = name;
this.creationDate= Calendar.getInstance().getTime();
}
}
和回購的這個例子：
public interface UserRepository extends JpaRepository<User, Long>, JpaSpecificationExecutor<User> {
public User findByName(String name);
}
但是，當我需要做的：
User user = new User();
我不能從再得到creationDate：
Calendar.getInstance().getTime();
因爲有些人正在改變操作系統的時間，並且創建的時間被持續錯誤。所以我需要一些：
SELECT SYSDATE FROM DUAL;
SELECT now();
從用戶設置creationDate。
我需要一個新的回購獲得時間，或者我可以使用此UserRepository從數據庫中獲取creationDate？我試過創建一個UtilsRepository，在那裏我可能會從數據庫中得到日期：
public interface UtilsRepository extends JpaRepository<Date, String> {
@Modifying
@Transactional(readOnly = false)
@Query("select now()")
public Date getDataBaseDate();
}
但它不工作。我收到這個錯誤，我認爲這不是最好的方法。發生
Exception in Application init method
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.launcher.LauncherHelper$FXHelper.main(Unknown Source)
Caused by: java.lang.RuntimeException: Exception in Application init method
at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:912)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$155(LauncherImpl.java:182)
at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'utilsRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Not a managed type: class java.util.Date
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1578)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:757)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:861)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759)
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:369)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:313)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1185)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1174)
at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:841)
... 2 more
Caused by: java.lang.IllegalArgumentException: Not a managed type: class java.util.Date
at org.hibernate.jpa.internal.metamodel.MetamodelImpl.managedType(MetamodelImpl.java:210)
at org.springframework.data.jpa.repository.support.JpaMetamodelEntityInformation.<init>(JpaMetamodelEntityInformation.java:68)
at org.springframework.data.jpa.repository.support.JpaEntityInformationSupport.getEntityInformation(JpaEntityInformationSupport.java:67)
at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getEntityInformation(JpaRepositoryFactory.java:152)
at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository(JpaRepositoryFactory.java:99)
at org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository(JpaRepositoryFactory.java:81)
at org.springframework.data.repository.core.support.RepositoryFactorySupport.getRepository(RepositoryFactorySupport.java:199)
at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.initAndReturn(RepositoryFactoryBeanSupport.java:266)
at org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.afterPropertiesSet(RepositoryFactoryBeanSupport.java:252)
at org.springframework.data.jpa.repository.support.JpaRepositoryFactoryBean.afterPropertiesSet(JpaRepositoryFactoryBean.java:92)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574)
... 18 more
我會說，如果「有人」是允許的，並如果改變生產服務器的時間，你會遇到比創建日期錯誤更大的問題。從數據庫獲取當前tme不會有太大變化，因爲這些人可能也會更改數據庫服務器上的時間。 –
爲什麼該方法被標註爲修改並且只讀爲false？ –
@JBNizet，在這種情況下，有必要這樣做。 – laccf