添加@Transactional导致＆＃34; java.lang.ClassCastException - ＆gt; java.lang.Class无法强制转换为java.lang.reflect.ParameterizedType＆＃34;例外

时间：2015-02-09 21:40:05

标签： spring dao autowired transactional

我正在使用Spring 3.2.11.RELEASE。我有一个类似下面的课...... 

@Repository("AssessmentImageDao")
@Transactional
public class MyObjectDao extends GenericDAO<MyObject> 
{

其中超类有

public GenericDAO() {
    this.persistentClass = (Class<T>) ((ParameterizedType) this.getClass().getGenericSuperclass()).getActualTypeArguments()[0];
}

然而，这导致以下例外...... 

[ERROR]: org.springframework.test.context.TestContextManager - Caught exception while allowing TestExecutionListener [org.springframework.test.context.support.DependencyInjectionTestExecutionListener@62b9a65b] to prepare test instance [com.myco.MyTest@7a252cf1]
java.lang.IllegalStateException: Failed to load ApplicationContext
    at org.springframework.test.context.CacheAwareContextLoaderDelegate.loadContext(CacheAwareContextLoaderDelegate.java:99)
    at org.springframework.test.context.TestContext.getApplicationContext(TestContext.java:122)
    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:211)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:288)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:284)
    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.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:264)
    at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:153)
    at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:124)
    at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:200)
    at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:153)
    at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:103)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'MyObjectDao' defined in file [/Users/davea/Dropbox/workspace/core/target/classes/org/mainco/subco/myproject/dao/MyObjectDao.class]: Initialization of bean failed; nested exception is org.springframework.aop.framework.AopConfigException: Could not generate CGLIB subclass of class [class org.mainco.subco.myproject.dao.MyObjectDao]: Common causes of this problem include using a final class or a non-visible class; nested exception is org.springframework.cglib.core.CodeGenerationException: java.lang.ClassCastException-->java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:529)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:293)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:290)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:191)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:636)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:934)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
    at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:120)
    at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:60)
    at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.delegateLoading(AbstractDelegatingSmartContextLoader.java:102)
    at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.loadContext(AbstractDelegatingSmartContextLoader.java:246)
    at org.springframework.test.context.CacheAwareContextLoaderDelegate.loadContextInternal(CacheAwareContextLoaderDelegate.java:64)
    at org.springframework.test.context.CacheAwareContextLoaderDelegate.loadContext(CacheAwareContextLoaderDelegate.java:91)
    ... 25 more

有没有办法重写构造函数以避免这种异常或做一些其他全局配置来解决问题？我正在尝试重新编码GenericDao类的每个子类的发票。

2 个答案:

答案 0 :(得分：2)

问题在于@Transactional注释是通过向类层次结构添加另一个层来实现的 - 一个扩展MyObjectDao以实现事务行为的代理类。对于此代理类的对象，this.getClass()是代理类，其getGenericSuperclass()是MyObjectDao本身，而不是参数化类型GenericDAO<MyObject>。

您可以稍微更改一下逻辑，这样您就可以继续查找getGenericSuperclass链，直到找到ParameterizedType - 如果父亲是Class您尝试祖父母，并且等等。

或者，看看是否可以推迟超类查找直到第一次实际需要它（当调用其中一个GenericDAO方法时）而不是在构造函数中执行它。虽然生成的代理类扩展了MyObjectDao，但它实际上从未在this上调用任何超类方法。代理拦截所有方法调用，执行事务逻辑，然后将业务逻辑委托给一个单独的目标对象，该目标对象是MyObjectDao的一个实例，而不是子类。

答案 1 :(得分：0)

您还可以使用多态并在public abstract Class<? extends MyObject> getHandledType()中创建GenericDAO方法，并使每个实现自我介绍。

或使用Spring Data。

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