我正在使用Hibernate 4.0.1.Final。如果该对象已通过org.hibernate.Session.load(Class clazz,Serializable id)方法加载并且没有活动的会话,是否可以访问该对象的字段?
我使用此代码通过id访问对象…
protected Object find(Class clazz, Serializable id) { Object obj = null; try { startOperation(); obj = session.load(clazz, id); tx.commit(); } catch (HibernateException e) { handleException(e); } finally { session.close(); } return obj; }
但是如果我的对象没有活动的会话,例如这段代码……
final Organization foundOrg = orgDao.findById(org.getOrganizationId()); System.out.println(foundOrg.getName());
我在“ System.out”行上收到此错误…
org.hibernate.LazyInitializationException: could not initialize proxy - no Session at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:149) at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:195) at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:185) at org.myco.myproject.orgsclient.model.Organization_$$_javassist_0.getName(Organization_$$_javassist_0.java) at org.myco.myproject.orgsclient.dao.OrganizationDAOTest.testInsertSchool(OrganizationDAOTest.java:43) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20) at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184) at org.junit.runners.ParentRunner.run(ParentRunner.java:236) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
使用session.get(Class, Serializable)代替session.load(Class, Serializable)
session.get(Class, Serializable)
session.load(Class, Serializable)
加载会将代理返回给该对象,当您首次访问代理上的属性时,将从数据库中加载该对象。如果使用session.get(),则可以保证会返回完全初始化的对象。
session.get()
加载和获取之间的另一个区别是找不到对象的结果。Get将返回null,而load将始终返回代理。访问属性时,此代理将引发异常。