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JPA提供商遠程調用的Hessian爲什麼JPA的FetchType.LAZY不起作用？
服務器側EJB + JPA 客戶端側平原搖擺的EclipseLink 2.3 AS的glassfish 3.1.1 B12 二進制協議。
JPA映射
@Entity
@Table(name = "FATHER", catalog = "CAT", schema = "dbo")
public class Father implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(generator = "FATHERUID", strategy = GenerationType.TABLE)
@TableGenerator(name = "FATHERUID", table = "FAMILY_UID", catalog = "LSDB", schema = "dbo", pkColumnName = "PRIM", pkColumnValue = "father_uid", valueColumnName = "UID", allocationSize = 1, initialValue = 0)
private Long id;
@OneToOne(mappedBy = "father", fetch = FetchType.LAZY)
private Mother mother;
@OneToMany(mappedBy = "father", fetch = FetchType.LAZY)
private List<Friend> friendList;
}
@Entity
@Table(name = "FRIEND", catalog = "CAT", schema = "dbo")
@NamedQueries({
@NamedQuery(name = "Friend.findAll", query = "SELECT f FROM Friend f")})
public class Friend implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(generator = "FRIENDUID", strategy = GenerationType.TABLE)
@TableGenerator(name = "FRIENDUID", table = "FAMILY_UID", catalog = "LSDB", schema = "dbo", pkColumnName = "PRIM", pkColumnValue = "friend_uid", valueColumnName = "UID", allocationSize = 1, initialValue = 0)
private Long id;
@JoinColumn(name = "FATHERID", referencedColumnName = "ID")
@ManyToOne(optional = false,fetch= FetchType.LAZY)
private Father father;
}
EJB方法
public Father findFather(long id) {
Father fath = em.find(Father.class, id);
PersistenceUnitUtil util = em.getEntityManagerFactory().getPersistenceUnitUtil();
System.out.println("mother isloaded="+util.isLoaded(fath,"mother"));
System.out.println("friendList isloaded="+util.isLoaded(fath,"friendList"));
return fath;
}
客戶端調用了黑森州
public void findFather() {
try {
IManager manager = ProxyHelper.getStub();
//find by father id
Father father = manager.findFather(3500L);
System.out.println("Father=" + father);
System.out.println("father's friends=" + father.getFriendList());
System.out.println("mother=" + father.getMother());
} catch (MalformedURLException ex) {
}
}
一切工作正常，但是當查看服務器日誌和Father實體相關方時，我發現 LazyLoaded anotated字段是從數據庫中填充的。
服務器日誌
FINEST: Begin deploying Persistence Unit test; session file:/C:/netbeans/projects/JPATestServer/build/web/WEB-INF/classes/_test; state Predeployed; factoryCount 1
INFO: Instantiated an instance of org.hibernate.validator.engine.resolver.JPATraversableResolver.
FINEST: property=eclipselink.target-server; value=SunAS9; translated value=org.eclipse.persistence.platform.server.sunas.SunAS9ServerPlatform
FINEST: property=eclipselink.logging.level; value=FINEST; translated value=FINEST
FINEST: property=eclipselink.logging.parameters; value=true
FINEST: property=eclipselink.logging.level; value=FINEST; translated value=FINEST
FINEST: property=eclipselink.logging.parameters; value=true
FINEST: property=eclipselink.cache.shared.default; value=false; translated value=false
INFO: EclipseLink, version: Eclipse Persistence Services - 2.3.2.v20111125-r10461
FINEST: Database platform: org.eclipse.persistence.platform.database.oracle.Oracle11Platform, regular expression: (?i)oracle.*11
FINEST: Database platform: org.eclipse.persistence.platform.database.oracle.Oracle10Platform, regular expression: (?i)oracle.*10
FINEST: Database platform: org.eclipse.persistence.platform.database.oracle.Oracle9Platform, regular expression: (?i)oracle.*9
FINEST: Database platform: org.eclipse.persistence.platform.database.oracle.OraclePlatform, regular expression: (?i)oracle.*
FINEST: Database platform: org.eclipse.persistence.platform.database.SQLAnywherePlatform, regular expression: SQL\ Anywhere.*
FINEST: Database platform: org.eclipse.persistence.platform.database.SybasePlatform, regular expression: (?i)(sybase.*)|(adaptive\ server\ enterprise.*)|(SQL\ Server.*)
FINEST: Database platform: org.eclipse.persistence.platform.database.SQLServerPlatform, regular expression: (?i)microsoft.*
FINE: Detected database platform: org.eclipse.persistence.platform.database.SQLServerPlatform
CONFIG: connecting(DatabaseLogin(
platform=>DatabasePlatform
user name=> ""
connector=>JNDIConnector datasource name=>null
))
CONFIG: Connected: jdbc:jtds:sqlserver:
User: user
Database: Microsoft SQL Server Version: 10.50.1600
Driver: jTDS Type 4 JDBC Driver for MS SQL Server and Sybase Version: 1.2.5
FINEST: Connection acquired from connection pool [read].
FINEST: Connection released to connection pool [read].
CONFIG: connecting(DatabaseLogin(
platform=>SQLServerPlatform
user name=> ""
connector=>JNDIConnector datasource name=>null
))
CONFIG: Connected: jdbc:jtds:sqlserver:
User: user
Database: Microsoft SQL Server Version: 10.50.1600
Driver: jTDS Type 4 JDBC Driver for MS SQL Server and Sybase Version: 1.2.5
FINEST: sequencing connected, state is Preallocation_Transaction_NoAccessor_State
FINEST: sequence child_uid: preallocation size 1
FINEST: sequence friend_uid: preallocation size 1
FINEST: sequence father_uid: preallocation size 1
FINEST: sequence mother_uid: preallocation size 1
INFO: file:/C:/netbeans/projects/JPATestServer/build/web/WEB-INF/classes/_test login successful
WARNING: Multiple [2] JMX MBeanServer instances exist, we will use the server at index [0] : [[email protected]].
FINER: JMX MBeanServer instance found: [[email protected]], # of beans: [21], domain: [DefaultDomain] at index: [0].
WARNING: JMX MBeanServer in use: [[email protected]] from index [0]
FINER: JMX MBeanServer instance found: [[email protected]], # of beans: [24], domain: [DefaultDomain] at index: [1].
WARNING: JMX MBeanServer in use: [[email protected]] from index [1]
FINEST: Registered MBean: org.eclipse.persistence.services.mbean.MBeanDevelopmentServices[TopLink:Name=Development-file_/C_/netbeans/projects/JPATestServer/build/web/WEB-INF/classes/_test,Type=Configuration] on server [email protected]
FINEST: Registered MBean: org.eclipse.persistence.services.glassfish.MBeanGlassfishRuntimeServices[TopLink:Name=Session(file_/C_/netbeans/projects/JPATestServer/build/web/WEB-INF/classes/_test)] on server [email protected]
FINEST: EclipseLink JMX Runtime Services is referencing the [Platform ConversionManager] ClassLoader at: [WebappClassLoader (delegate=true; repositories=WEB-INF/classes/)]
FINEST: The applicationName for the MBean attached to session [file:/C:/netbeans/projects/JPATestServer/build/web/WEB-INF/classes/_test] is [unknown]
FINEST: The moduleName for the MBean attached to session [file:/C:/netbeans/projects/JPATestServer/build/web/WEB-INF/classes/_test] is [unknown]
FINER: Canonical Metamodel class [org.dima.model.Child_] not found during initialization.
FINER: Canonical Metamodel class [org.dima.model.Friend_] not found during initialization.
FINER: Canonical Metamodel class [org.dima.model.Father_] not found during initialization.
FINER: Canonical Metamodel class [org.dima.model.Mother_] not found during initialization.
FINEST: End deploying Persistence Unit test; session file:/C:/netbeans/projects/JPATestServer/build/web/WEB-INF/classes/_test; state Deployed; factoryCount 1
FINER: client acquired: 50658177
FINER: TX binding to tx mgr, status=STATUS_ACTIVE
FINER: acquire unit of work: 1008456627
FINEST: Execute query ReadObjectQuery(name="readObject" referenceClass=Father sql="SELECT ID, NAME, SURNAME FROM LSDB.dbo.FATHER WHERE (ID = ?)")
FINEST: Connection acquired from connection pool [read].
FINEST: reconnecting to external connection pool
FINE: SELECT ID, NAME, SURNAME FROM LSDB.dbo.FATHER WHERE (ID = ?)
bind => [3500]
FINEST: Connection released to connection pool [read].
INFO: mother isloaded=false
INFO: friendList isloaded=false
FINER: TX beforeCompletion callback, status=STATUS_ACTIVE
FINER: begin unit of work commit
FINER: TX afterCompletion callback, status=COMMITTED
FINER: end unit of work commit
FINER: release unit of work
FINER: client released
FINEST: Execute query ReadAllQuery(name="file:/C:/netbeans/projects/JPATestServer/build/web/WEB-INF/classes/_test" referenceClass=Friend)
FINEST: Connection acquired from connection pool [read].
FINEST: reconnecting to external connection pool
**FINE: SELECT ID, NAME, SURNAME, FATHERID FROM LSDB.dbo.FRIEND WHERE (FATHERID = ?)
bind => [3500]**
FINEST: Connection released to connection pool [read].
FINEST: Register the existing object org.dima.model.Friend[ id=17496 ]
FINEST: Register the existing object org.dima.model.Friend[ id=17497 ]
FINEST: Register the existing object org.dima.model.Friend[ id=17498 ]
FINEST: Register the existing object org.dima.model.Friend[ id=17499 ]
FINEST: Register the existing object org.dima.model.Friend[ id=17500 ]
爲什麼JPA提供商執行該 SELECT ID，名字，姓氏，FATHERID FROM LSDB.dbo.FRIEND WHERE（FATHERID =？） 綁定=> [3500]
有什麼想法？
是不是（觸發）列表的toString（）方法觸發延遲加載的（隱式）調用？ – 2011-12-14 15:17:01
另外，我發現這種行爲（事務提交後的延遲加載）可疑：如果事務具有READ_COMMITTED（或更嚴格）隔離級別，則在事務結束後延遲加載列表允許查看不存在的子項當事務運行時，並且不顯示事務運行但已被刪除的子項。你在ACID中失去了I和C. – 2011-12-14 15:21:24