云南省建设厅勘察设计处网站,wordpress静态化html,进度跟踪网站开发,迪庆网站建设介绍 既然您了解了Hibernate脏检查的基础知识 #xff0c;我们就可以研究增强的脏检查机制。 虽然默认的图遍历算法对于大多数用例可能已足够#xff0c;但有时您需要优化的脏检查算法#xff0c;并且检测方法比构建自己的自定义策略更方便。 使用Ant休眠工具 传统上#… 介绍 既然您了解了Hibernate脏检查的基础知识 我们就可以研究增强的脏检查机制。 虽然默认的图遍历算法对于大多数用例可能已足够但有时您需要优化的脏检查算法并且检测方法比构建自己的自定义策略更方便。 使用Ant休眠工具 传统上Hibernate Tools一直专注于Ant和Eclipse。 从Hibernate 3开始就可以进行字节码检测但是它需要Ant任务才能运行CGLIB或Javassist字节码增强例程。 Maven支持通过maven-antrun-plugin运行Ant任务 buildpluginspluginartifactIdmaven-antrun-plugin/artifactIdexecutionsexecutionidInstrument domain classes/idconfigurationtaskstaskdef nameinstrumentclassnameorg.hibernate.tool.instrument.javassist.InstrumentTaskclasspathpath refidmaven.dependency.classpath/path refidmaven.plugin.classpath//classpath/taskdefinstrument verbosetruefileset dir${project.build.outputDirectory}include name**/flushing/*.class//fileset/instrument/tasks/configurationphaseprocess-classes/phasegoalsgoalrun/goal/goals/execution/executionsdependenciesdependencygroupIdorg.hibernate/groupIdartifactIdhibernate-core/artifactIdversion${hibernate.version}/version/dependencydependencygroupIdorg.javassist/groupIdartifactIdjavassist/artifactIdversion${javassist.version}/version/dependency/dependencies/plugin/plugins
/build 因此对于以下实体源类 Entity
public class EnhancedOrderLine {IdGeneratedValue(strategy GenerationType.AUTO)private Long id;private Long number;private String orderedBy;private Date orderedOn;public Long getId() {return id;}public Long getNumber() {return number;}public void setNumber(Long number) {this.number number;}public String getOrderedBy() {return orderedBy;}public void setOrderedBy(String orderedBy) {this.orderedBy orderedBy;}public Date getOrderedOn() {return orderedOn;}public void setOrderedOn(Date orderedOn) {this.orderedOn orderedOn;}
} 在构建期间将生成以下类 Entity
public class EnhancedOrderLine implements FieldHandled {IdGeneratedValue(strategyGenerationType.AUTO)private Long id;private Long number;private String orderedBy;private Date orderedOn;private transient FieldHandler $JAVASSIST_READ_WRITE_HANDLER;public Long getId() {return $javassist_read_id();}public Long getNumber() {return $javassist_read_number();}public void setNumber(Long number) {$javassist_write_number(number);}public String getOrderedBy() {return $javassist_read_orderedBy();}public void setOrderedBy(String orderedBy) {$javassist_write_orderedBy(orderedBy);}public Date getOrderedOn() {return $javassist_read_orderedOn();}public void setOrderedOn(Date orderedOn) {$javassist_write_orderedOn(orderedOn);}public FieldHandler getFieldHandler() {return this.$JAVASSIST_READ_WRITE_HANDLER;}public void setFieldHandler(FieldHandler paramFieldHandler) {this.$JAVASSIST_READ_WRITE_HANDLER paramFieldHandler;}public Long $javassist_read_id() {if (getFieldHandler() null)return this.id;}public void $javassist_write_id(Long paramLong) {if (getFieldHandler() null) {this.id paramLong;return;}this.id ((Long)getFieldHandler().writeObject(this, id, this.id, paramLong));}public Long $javassist_read_number() {if (getFieldHandler() null)return this.number;}public void $javassist_write_number(Long paramLong) {if (getFieldHandler() null) {this.number paramLong;return;}this.number ((Long)getFieldHandler().writeObject(this, number, this.number, paramLong));}public String $javassist_read_orderedBy() {if (getFieldHandler() null)return this.orderedBy;}public void $javassist_write_orderedBy(String paramString) {if (getFieldHandler() null) {this.orderedBy paramString;return;}this.orderedBy ((String)getFieldHandler().writeObject(this, orderedBy, this.orderedBy, paramString));}public Date $javassist_read_orderedOn() {if (getFieldHandler() null)return this.orderedOn;}public void $javassist_write_orderedOn(Date paramDate) {if (getFieldHandler() null) {this.orderedOn paramDate;return;}this.orderedOn ((Date)getFieldHandler().writeObject(this, orderedOn, this.orderedOn, paramDate));}
} 尽管org.hibernate.bytecode.instrumentation.spi.AbstractFieldInterceptor设法拦截脏字段但在进行脏污跟踪时从未真正询问过此信息。 InstrumentTask字节码增强功能只能分辨一个实体是否脏了缺乏对指示已修改哪些属性的支持因此使InstrumentTask更适合“ No-proxy” LAZY提取策略 。 休眠增强Maven插件 Hibernate 4.2.8增加了对专用Maven字节码增强插件的支持 。 Maven字节码增强插件易于配置 buildpluginsplugingroupIdorg.hibernate.orm.tooling/groupIdartifactIdhibernate-enhance-maven-plugin/artifactIdexecutionsexecutionphasecompile/phasegoalsgoalenhance/goal/goals/execution/executions/plugin/plugins
/build 在项目构建期间将生成以下类 Entity
public class EnhancedOrderLineimplements ManagedEntity, PersistentAttributeInterceptable, SelfDirtinessTracker {IdGeneratedValue(strategy GenerationType.AUTO)private Long id;private Long number;private String orderedBy;private Date orderedOn;Transientprivate transient PersistentAttributeInterceptor $$_hibernate_attributeInterceptor;Transientprivate transient Set $$_hibernate_tracker;Transientprivate transient CollectionTracker $$_hibernate_collectionTracker;Transientprivate transient EntityEntry $$_hibernate_entityEntryHolder;Transientprivate transient ManagedEntity $$_hibernate_previousManagedEntity;Transientprivate transient ManagedEntity $$_hibernate_nextManagedEntity;public Long getId() {return $$_hibernate_read_id();}public Long getNumber() {return $$_hibernate_read_number();}public void setNumber(Long number) {$$_hibernate_write_number(number);}public String getOrderedBy() {return $$_hibernate_read_orderedBy();}public void setOrderedBy(String orderedBy) {$$_hibernate_write_orderedBy(orderedBy);}public Date getOrderedOn() {return $$_hibernate_read_orderedOn();}public void setOrderedOn(Date orderedOn) {$$_hibernate_write_orderedOn(orderedOn);}public PersistentAttributeInterceptor $$_hibernate_getInterceptor() {return this.$$_hibernate_attributeInterceptor;}public void $$_hibernate_setInterceptor(PersistentAttributeInterceptor paramPersistentAttributeInterceptor) {this.$$_hibernate_attributeInterceptor paramPersistentAttributeInterceptor;}public void $$_hibernate_trackChange(String paramString) {if (this.$$_hibernate_tracker null)this.$$_hibernate_tracker new HashSet();if (!this.$$_hibernate_tracker.contains(paramString))this.$$_hibernate_tracker.add(paramString);}private boolean $$_hibernate_areCollectionFieldsDirty() {return ($$_hibernate_getInterceptor() ! null) (this.$$_hibernate_collectionTracker ! null);}private void $$_hibernate_getCollectionFieldDirtyNames(Set paramSet) {if (this.$$_hibernate_collectionTracker null)return;}public boolean $$_hibernate_hasDirtyAttributes() {return ((this.$$_hibernate_tracker null) || (this.$$_hibernate_tracker.isEmpty())) ($$_hibernate_areCollectionFieldsDirty());}private void $$_hibernate_clearDirtyCollectionNames() {if (this.$$_hibernate_collectionTracker null)this.$$_hibernate_collectionTracker new CollectionTracker();}public void $$_hibernate_clearDirtyAttributes() {if (this.$$_hibernate_tracker ! null)this.$$_hibernate_tracker.clear();$$_hibernate_clearDirtyCollectionNames();}public SetString $$_hibernate_getDirtyAttributes() {if (this.$$_hibernate_tracker null)this.$$_hibernate_tracker new HashSet();$$_hibernate_getCollectionFieldDirtyNames(this.$$_hibernate_tracker);return this.$$_hibernate_tracker;}private Long $$_hibernate_read_id() {if ($$_hibernate_getInterceptor() ! null)this.id ((Long) $$_hibernate_getInterceptor().readObject(this, id, this.id));return this.id;}private void $$_hibernate_write_id(Long paramLong) {if (($$_hibernate_getInterceptor() null) || ((this.id null) || (this.id.equals(paramLong))))break label39;$$_hibernate_trackChange(id);label39:Long localLong paramLong;if ($$_hibernate_getInterceptor() ! null)localLong (Long) $$_hibernate_getInterceptor().writeObject(this, id, this.id, paramLong);this.id localLong;}private Long $$_hibernate_read_number() {if ($$_hibernate_getInterceptor() ! null)this.number ((Long) $$_hibernate_getInterceptor().readObject(this, number, this.number));return this.number;}private void $$_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;}private String $$_hibernate_read_orderedBy() {if ($$_hibernate_getInterceptor() ! null)this.orderedBy ((String) $$_hibernate_getInterceptor().readObject(this, orderedBy, this.orderedBy));return this.orderedBy;}private void $$_hibernate_write_orderedBy(String paramString) {if (($$_hibernate_getInterceptor() null) || ((this.orderedBy null) || (this.orderedBy.equals(paramString))))break label39;$$_hibernate_trackChange(orderedBy);label39:String str paramString;if ($$_hibernate_getInterceptor() ! null)str (String) $$_hibernate_getInterceptor().writeObject(this, orderedBy, this.orderedBy, paramString);this.orderedBy str;}private Date $$_hibernate_read_orderedOn() {if ($$_hibernate_getInterceptor() ! null)this.orderedOn ((Date) $$_hibernate_getInterceptor().readObject(this, orderedOn, this.orderedOn));return this.orderedOn;}private void $$_hibernate_write_orderedOn(Date paramDate) {if (($$_hibernate_getInterceptor() null) || ((this.orderedOn null) || (this.orderedOn.equals(paramDate))))break label39;$$_hibernate_trackChange(orderedOn);label39:Date localDate paramDate;if ($$_hibernate_getInterceptor() ! null)localDate (Date) $$_hibernate_getInterceptor().writeObject(this, orderedOn, this.orderedOn, paramDate);this.orderedOn localDate;}public Object $$_hibernate_getEntityInstance() {return this;}public EntityEntry $$_hibernate_getEntityEntry() {return this.$$_hibernate_entityEntryHolder;}public void $$_hibernate_setEntityEntry(EntityEntry paramEntityEntry) {this.$$_hibernate_entityEntryHolder paramEntityEntry;}public ManagedEntity $$_hibernate_getPreviousManagedEntity() {return this.$$_hibernate_previousManagedEntity;}public void $$_hibernate_setPreviousManagedEntity(ManagedEntity paramManagedEntity) {this.$$_hibernate_previousManagedEntity paramManagedEntity;}public ManagedEntity $$_hibernate_getNextManagedEntity() {return this.$$_hibernate_nextManagedEntity;}public void $$_hibernate_setNextManagedEntity(ManagedEntity paramManagedEntity) {this.$$_hibernate_nextManagedEntity paramManagedEntity;}
} 很容易意识到新的字节码增强逻辑与以前的InstrumentTask生成的逻辑不同。 与自定义脏检查机制类似新的字节码增强版本记录了已更改的属性而不仅仅是一个简单的脏布尔标志。 更改时增强逻辑会标记脏字段。 这种方法比必须将所有当前属性值与加载时快照数据进行比较要有效得多。 我们到了吗 即使实体类字节码得到了增强使用Hibernate 4.3.6 仍然以某种方式缺少一些拼图 。 例如当调用setNumberLong number时 将执行以下拦截方法 private void $$_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;} 在我的示例中$$ _ hibernate_getInterceptor始终为null从而绕过$$ _ hibernate_trackChange“ number”调用。 因此将不会记录任何脏属性从而迫使Hibernate退回到默认的深度比较脏检查算法 。 因此即使Hibernate在该特定领域取得了长足的进步肮脏检查的增强仍然需要额外的工作才能变得容易获得。 代码可在GitHub上获得 。 翻译自: https://www.javacodegeeks.com/2014/09/hibernate-bytecode-enhancement.html
