Hibernate 4字节码增强功能不适用于脏检查优化

小编典典

Hibernate 4字节码增强功能不适用于脏检查优化

java

我正在使用Hibernate
4.3.6，并且使用了最新的Maven字节码增强功能来检测所有实体是否具有自我污染意识。

我添加了Maven插件：

<build>
    <plugins>
        <plugin>
            <groupId>org.hibernate.orm.tooling</groupId>
            <artifactId>hibernate-enhance-maven-plugin</artifactId>
            <executions>
                <execution>
                    <phase>process-test-resources</phase>
                    <goals>
                        <goal>enhance</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

而且我看到我的实体得到了增强：

@Entity
public class EnhancedOrderLine
implements ManagedEntity, PersistentAttributeInterceptable, SelfDirtinessTracker
{
    @Id
  @GeneratedValue(strategy=GenerationType.AUTO)
  private Long id;
  private Long number;
  private String orderedBy;
  private Date orderedOn;

  @Transient
  private transient PersistentAttributeInterceptor $$_hibernate_attributeInterceptor;

  @Transient
  private transient Set $$_hibernate_tracker;

  @Transient
  private transient CollectionTracker $$_hibernate_collectionTracker;

  @Transient
  private transient EntityEntry $$_hibernate_entityEntryHolder;

  @Transient
  private transient ManagedEntity $$_hibernate_previousManagedEntity;

  @Transient
  private transient ManagedEntity $$_hibernate_nextManagedEntity;

  ...

调试时，我正在检查org.hibernate.event.internal.DefaultFlushEntityEventListener#dirtyCheck方法：

        if ( entity instanceof SelfDirtinessTracker ) {
            if ( ( (SelfDirtinessTracker) entity ).$$_hibernate_hasDirtyAttributes() ) {
                dirtyProperties = persister.resolveAttributeIndexes( ( (SelfDirtinessTracker) entity ).$$_hibernate_getDirtyAttributes() );
            }
        }

并且$$_hibernate_hasDirtyAttributes()始终返回 false 。

这是因为$$_hibernate_attributeInterceptor始终为null，因此在设置任何属性时：

private void $$_hibernate_write_number(Long paramLong)
{
 if (($$_hibernate_getInterceptor() == null) || ((this.number == null) || (this.number.equals(paramLong))))
  break label39;
 $$_hibernate_trackChange("number");
 label39: Long localLong = paramLong;
 if ($$_hibernate_getInterceptor() != null)
  localLong = (Long)$$_hibernate_getInterceptor().writeObject(this, "number", this.number, paramLong);
 this.number = localLong;
}

因为$$_hibernate_getInterceptor()为null，将绕过trackChange，因此字节码增强功能将无法解决脏属性，并且将使用默认的深度比较算法。

我想念什么？如何$$_hibernate_attributeInterceptor正确设置，以便字节码检测方法可以跟踪脏属性？

阅读 223

2020-12-03

共1个答案

小编典典

Hibernate 5解决了此问题，现在对setter的脏检查如下所示：

public void $$_hibernate_write_title(String paramString)
{
    if (!EqualsHelper.areEqual(this.title, paramString)) {
      $$_hibernate_trackChange("title");
    }
    this.title = paramString;
}

public void $$_hibernate_trackChange(String paramString)
{
    if (this.$$_hibernate_tracker == null) {
      this.$$_hibernate_tracker = new SimpleFieldTracker();
    }
    this.$$_hibernate_tracker.add(paramString);
}

因此，解决方案是对Hibernate 5的升级。

2020-12-03