Java hibernate条件上的LazyInitializationException错误+;限制(弹簧)
在使用hibernate获取查询时,我遇到了这个错误Java hibernate条件上的LazyInitializationException错误+;限制(弹簧),java,spring,hibernate,jakarta-ee,spring-mvc,Java,Spring,Hibernate,Jakarta Ee,Spring Mvc,在使用hibernate获取查询时,我遇到了这个错误 org.hibernate.LazyInitializationException: could not initialize proxy - no Session at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:167) at org.hibernate.proxy.AbstractLazyIniti
org.hibernate.LazyInitializationException: could not initialize proxy - no Session
at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:167)
at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:215)
at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:190)
at com.javalabs.web.dao.Task_$$_javassist_1.toString(Task_$$_javassist_1.java)
at java.lang.String.valueOf(Unknown Source)
at java.lang.StringBuilder.append(Unknown Source)
at com.javalabs.web.dao.TaskAction.toString(TaskAction.java:175)
at java.lang.String.valueOf(Unknown Source)
at java.lang.StringBuilder.append(Unknown Source)
at java.util.AbstractCollection.toString(Unknown Source)
at java.lang.String.valueOf(Unknown Source)
at org.junit.Assert.format(Assert.java:752)
at org.junit.Assert.failNotEquals(Assert.java:743)
at org.junit.Assert.assertEquals(Assert.java:118)
at com.javalabs.web.test.tests.TaskActionDaoTests.testTaskActionCreate(TaskActionDaoTests.java:120)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:88)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
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:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
抛出错误的JUnit测试
@Test
public void testTaskActionCreate() {
taskPriorityDao.saveOrUpdate(priority);
taskCategoryDao.saveOrUpdate(category);
taskStateDao.saveOrUpdate(state);
userDao.saveOrUpdate(user);
Date rightnow = Calendar.getInstance().getTime();
Task t1 = new Task("My first task", "This is a task", rightnow,
rightnow, category, priority, state, user, user, "okey", 0);
TaskAction ta1 = new TaskAction(t1, rightnow, "Task action 1",
"Task action 1 description", user);
TaskAction ta2 = new TaskAction(t1, rightnow, "Task action 2",
"Task action 2 description", user);
TaskAction ta3 = new TaskAction(t1, rightnow, "Task action 3",
"Task action 3 description", user);
TaskAction ta4 = new TaskAction(t1, rightnow, "Task action 4",
"Task action 4 description", user);
t1.addAction(ta1);
t1.addAction(ta2);
t1.addAction(ta3);
t1.addAction(ta4);
taskDao.save(t1);
Task t2 = taskDao.get(t1.getIdTask());
assertEquals("Should be 4 taskActions with getAllTaskActions.", 4,
taskActionDao.getAllTaskActions(t2.getIdTask()));
}
TaskActionDao.java
...
@SuppressWarnings("unchecked")
public List<TaskAction> getAllTaskActions(long idTask) {
Criteria crit = session().createCriteria(TaskAction.class);
crit.add(Restrictions.eq("task.idTask", idTask)); //error task.idTask?
return crit.list();
}
...
@Entity
@Table(name = "t_taskaction")
public class TaskAction {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "idTaskAction")
private long idTaskAction;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "idTask", nullable = false)
private Task task;
private Date date;
private String actionname;
private String description;
private int duration;
@ManyToOne
@JoinColumn(name = "idUser", nullable = false)
private User user;
private Date timestamp;
...
@Entity
@Table(name = "t_task")
public class Task {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "idTask")
private long idTask;
...
Task.java
...
@SuppressWarnings("unchecked")
public List<TaskAction> getAllTaskActions(long idTask) {
Criteria crit = session().createCriteria(TaskAction.class);
crit.add(Restrictions.eq("task.idTask", idTask)); //error task.idTask?
return crit.list();
}
...
@Entity
@Table(name = "t_taskaction")
public class TaskAction {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "idTaskAction")
private long idTaskAction;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "idTask", nullable = false)
private Task task;
private Date date;
private String actionname;
private String description;
private int duration;
@ManyToOne
@JoinColumn(name = "idUser", nullable = false)
private User user;
private Date timestamp;
...
@Entity
@Table(name = "t_task")
public class Task {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "idTask")
private long idTask;
...
您可以得到一个
lazyiinitializationexception
。由于您在TaskAction
上隐式使用toString
,task
正在尝试被访问,而该任务是延迟加载的
如果尝试
assertEquals(“应该是4个taskActions和getAllTaskActions。”,4个taskActionDao.getAllTaskActions(t2.getIdTask()).size())代码>你能提供完整的堆栈跟踪吗?而且,列表不可能等于4。我只是为了简单起见,放了一行,但有4个任务操作。你可以得到一个LazyInitializationException
。由于您在TaskAction
上隐式地使用toString
,task
正在尝试被延迟加载的访问。如果尝试assertEquals(“应该是4个taskActions和getAllTaskActions。”,4个taskActionDao.getAllTaskActions(t2.getIdTask()).size())代码>你应该很好。让我知道什么happens@Joe我添加了它作为未来读者看到的答案