我对 Spring + Hibernate 非常陌生，我正在运行测试以查看我的 DAO 是否正常工作。我收到以下错误，在 Google 中搜索时会产生很多不同的答案(主要是我检查过的错别字)。我希望你能帮我解决这个问题:
java.lang.IllegalStateException: Failed to load ApplicationContext
at org.springframework.test.context.TestContext.getApplicationContext(TestContext.java:308)
at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:109)
at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:75)
at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:321)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:220)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:301)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:303)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:240)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49)
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.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:180)
at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:71)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:199)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:62)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'nominationDao' defined in file [C:\IdeaProjects\Projects\branch\dev\test-dataacess\target\classes\com\dev\test\data\dao\hibernate\NominationHibernateDAO.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.dev.test.data.dao.hibernate.NominationHibernateDAO]: Constructor threw exception; nested exception is java.lang.ClassCastException: sun.reflect.generics.reflectiveObjects.TypeVariableImpl cannot be cast to java.lang.Class
at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:288)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1003)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:907)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:485)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:580)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:900)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:455)
at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:84)
at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:1)
at org.springframework.test.context.TestContext.loadApplicationContext(TestContext.java:280)
at org.springframework.test.context.TestContext.getApplicationContext(TestContext.java:304)
... 27 more
Caused by: org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.dev.test.data.dao.hibernate.NominationHibernateDAO]: Constructor threw exception; nested exception is java.lang.ClassCastException: sun.reflect.generics.reflectiveObjects.TypeVariableImpl cannot be cast to java.lang.Class
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:162)
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:108)
at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:280)
... 42 more
Caused by: java.lang.ClassCastException: sun.reflect.generics.reflectiveObjects.TypeVariableImpl cannot be cast to java.lang.Class
at com.dev.test.data.dao.hibernate.AbstractHibernateDAO.<init>(AbstractHibernateDAO.java:50)
at com.dev.test.data.dao.hibernate.NominationHibernateDAO.<init>(NominationHibernateDAO.java:36)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:147)
... 44 more
什么可能导致这种情况？如果我在 AbstractHibernateDAO 和 NominationHibernateDAO 中进行了编辑，请告诉我。
谢谢!
编辑这里是片段:
这是 AbstractHibernateDAO 的片段，第 50 行是注释:
public abstract class AbstractHibernateDAO<T, K extends Serializable>
implements DAO<T, K> {
protected Logger logger = LoggerFactory.getLogger(this.getClass());
private SessionFactory sessionFactory;
private Class<T> persistentClass;
protected AbstractHibernateDAO(SessionFactory sessionFactory) {
this.sessionFactory = sessionFactory;
this.persistentClass = (Class<T>) ((ParameterizedType) //LINE 50
getClass().getGenericSuperclass()).getActualTypeArguments()[0];
}
第 36 行之后是对 NominationHibernateDAO 的这个片段的评论:
@Repository("nominationDao")
public class NominationHibernateDAO<T extends Nomination>
extends AbstractHibernateDAO<T,Integer>
implements NominationDAO<T> {
@Autowired(required = true)
public NominationHibernateDAO(SessionFactory sessionFactory) {
super(sessionFactory); //LINE 36
}
最佳答案
表达方式
getClass().getGenericSuperclass()).getActualTypeArguments()[0]
指代替换为
AbstractHibernateDAO 的第一个类型参数的值(在 AbstractHibernateDAO.java 中由 T 表示)。子类 NominationHibernateDAO 替代的类型还是不具体，是 T extends Nomination ，绝对不是 java.lang.Class 实例，而是 Type 实例( TypeVariableImpl 是 Type 的实现)。如果
NominationHibernateDAO 是这样声明的:class NominationHibernateDAO extends AbstractHibernateDAO<Nomination, Integer> { ...
那么
AbstractHibernateDAO 构造函数魔术就会起作用。或者，您可以(或者您甚至应该？)实例化一个 NominationHibernateDAO 的子类，声明如下:class ConcreteNominationHibernateDAO
extends NominationHibernateDAO<ConcreteNominationSubclass> { ...
或者
new NominationHibernateDAO<ConcreteNominationSubclass>() {}
这同样不会引发问题。
您确定
NominationHibernateDAO 类是用作 Spring bean 的吗？关于java - 错误测试 DAO : sun. reflect.generics.reflectiveObjects.TypeVariableImpl 不能转换为 java.lang.Class，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/8917733/