JPA中EntityListeners注解的使用详解

Z时代
2024-01-10
分类：综合

使用场景

EntityListeners在jpa中使用，如果你是mybatis是不可以用的

它的意义

对实体属性变化的跟踪，它提供了保存前，保存后，更新前，更新后，删除前，删除后等状态，就像是拦截器一样，你可以在拦截方法里重写你的个性化逻辑。

它的使用

定义接口，如实体追踪


/**
 * 数据建立与更新.
 */
public interface DataEntity {
 Timestamp getDateCreated();
 void setDateCreated(Timestamp dateCreated);
 Timestamp getLastUpdated();
 void setLastUpdated(Timestamp lastUpdated);
 Long getDateCreatedOn();
 void setDateCreatedOn(Long dateCreatedOn);
 Long getLastUpdatedOn();
 void setLastUpdatedOn(Long lastUpdatedOn);
}

定义跟踪器


@Slf4j
@Component
@Transactional
public class DataEntityListener {
 @PrePersist
 public void prePersist(DataEntity object)
   throws IllegalArgumentException, IllegalAccessException {
  Timestamp now = Timestamp.from(Instant.now());
  object.setDateCreated(now);
  object.setLastUpdated(now);
  logger.debug("save之前的操作");
 }
 @PostPersist
 public void postpersist(DataEntity object)
   throws IllegalArgumentException, IllegalAccessException {
  logger.debug("save之后的操作");
 }
 @PreUpdate
 public void preUpdate(DataEntity object)
   throws IllegalArgumentException, IllegalAccessException {
  Timestamp now = Timestamp.from(Instant.now());
  object.setLastUpdated(now);
  logger.debug("update之前的操作");
 }
 @PostUpdate
 public void postUpdate(DataEntity object)
   throws IllegalArgumentException, IllegalAccessException {
  logger.debug("update之后的操作");
 }
 @PreRemove
 public void preRemove(DataEntity object) {
  logger.debug("del之前的操作");
 }
 @PostRemove
 public void postRemove(DataEntity object) {
  logger.debug("del之后的操作");
 }
}

实体去实现这个对应的跟踪接口


@EntityListeners(DataEntityListener.class)
public class Product implements DataEntity {
   @Override
 public Timestamp getDateCreated() {
  return createTime;
 }
 @Override
 public void setDateCreated(Timestamp dateCreated) {
  createTime = dateCreated;
 }
 @Override
 public Timestamp getLastUpdated() {
  return lastUpdateTime;
 }
 @Override
 public void setLastUpdated(Timestamp lastUpdated) {
  this.lastUpdateTime = lastUpdated;
 }
 @Override
 public Long getDateCreatedOn() {
  return createOn;
 }
 @Override
 public void setDateCreatedOn(Long dateCreatedOn) {
  createOn = dateCreatedOn;
 }
 @Override
 public Long getLastUpdatedOn() {
  return lastUpdateOn;
 }
 @Override
 public void setLastUpdatedOn(Long lastUpdatedOn) {
  this.lastUpdateOn = lastUpdatedOn;
 }
}