@EntityListeners(AuditingEntityListener.class)介绍

@EntityListeners

源码

/**
 * Specifies the callback listener classes to be used for an
 * entity or mapped superclass. This annotation may be applied
 * to an entity class or mapped superclass.
 *
 * @since Java Persistence 1.0
 */
@Target({TYPE})
@Retention(RUNTIME)
public @interface EntityListeners {

    /** The callback listener classes */
    Class[] value();
}

分析

从源码的注释中可以很清楚的了解到该注解的作用，简单翻译如下：该注解用于指定Entity或者superclass上的回调监听类。该注解可以用于Entity或者superclass上。

AuditingEntityListener.class

源码

/**
 * JPA entity listener to capture auditing information on persiting and updating entities. To get this one flying be
 * sure you configure it as entity listener in your {@code orm.xml} as follows:
 * 
 * 
 * <persistence-unit-metadata>
 *     <persistence-unit-defaults>
 *         <entity-listeners>
 *             <entity-listener class="org.springframework.data.jpa.domain.support.AuditingEntityListener" />
 *         </entity-listeners>
 *     </persistence-unit-defaults>
 * </persistence-unit-metadata>
 * 
 * 
 * After that it's just a matter of activating auditing in your Spring config:
 * 
 * 
 * @Configuration
 * @EnableJpaAuditing
 * class ApplicationConfig {
 * 
 * }
 * 
 * 
 * 
 * <jpa:auditing auditor-aware-ref="yourAuditorAwarebean" />
 * 
 * 
 * @author Oliver Gierke
 * @author Thomas Darimont
 */
@Configurable
public class AuditingEntityListener {

	private ObjectFactory handler;

	/**
	 * Configures the {@link AuditingHandler} to be used to set the current auditor on the domain types touched.
	 * 
	 * @param auditingHandler must not be {@literal null}.
	 */
	public void setAuditingHandler(ObjectFactory auditingHandler) {

		Assert.notNull(auditingHandler, "AuditingHandler must not be null!");
		this.handler = auditingHandler;
	}

	/**
	 * Sets modification and creation date and auditor on the target object in case it implements {@link Auditable} on
	 * persist events.
	 * 
	 * @param target
	 */
	@PrePersist
	public void touchForCreate(Object target) {
		if (handler != null) {
			handler.getObject().markCreated(target);
		}
	}

	/**
	 * Sets modification and creation date and auditor on the target object in case it implements {@link Auditable} on
	 * update events.
	 * 
	 * @param target
	 */
	@PreUpdate
	public void touchForUpdate(Object target) {
		if (handler != null) {
			handler.getObject().markModified(target);
		}
	}
}

分析

同样的从该类的注释也可以了解到该类的作用：这是一个JPA Entity Listener，用于捕获监听信息，当Entity发生持久化和更新操作时。