我使用泛型创建了接口和类的层次结构，并搞砸了所有内容。
最顶级的类是AbstractJpaEntity，它由所有域实体
@MappedSuperclass
@EntityListeners({AbstractJpaEntity.AbstractEntityListener.class})
@SuppressWarnings("serial")
public class AbstractJpaEntity implements Serializable
ProductTypeDomain类就像用于分隔少数表实体的标记类。
@SuppressWarnings("serial")
@MappedSuperclass
@EntityListeners({ ProductTypeDomain.AbstractEntityListener.class })
public class ProductTypeDomain extends AbstractJpaEntity{}
Interface＆＃34; GenericDao＆＃34;定义
public interface GenericDao<T> {...
抽象类GenericDaoImpl（此类具有通用函数，如persist，merge）
public abstract class GenericDaoImpl<T extends AbstractJpaEntity> implements GenericDao<T> {...
接口ProductTypeDao
public interface ProductTypeDao<T extends ProductTypeDomain> extends GenericDao<T> {
Spring存储库类ProductTypeDaoImpl
@Repository("productTypeDao")
public class ProductTypeDaoImpl extends GenericDaoImpl implements ProductTypeDao
{....
在Spring服务类ProductManagerServiceimpl中，我正在自动装配存储库productTypeDao
@Service("productManager")
public class ProductManagerServiceimpl implements ProductManagerService{
@Autowired
ProductTypeDao productTypeDao;
在运行代码时，它会给我以下错误
引起：org.springframework.beans.factory.BeanCreationException：无法自动装配字段：com.jodo.cms.service.ProductManagerService com.jodo.cms.controllers.ProductController.productManager;嵌套异常是org.springframework.beans.factory.BeanCreationException：创建名为＆＃39; productManager＆＃39;的注册自动连接依赖项失败;嵌套异常是org.springframework.beans.factory.BeanCreationException：无法自动装配字段：com.jodo.cms.dao.ProductTypeDao com.jodo.cms.service.impl.ProductManagerServiceimpl.productTypeDao;嵌套异常是org.springframework.beans.factory.BeanCreationException：创建名称为＆＃39; productTypeDao＆＃39;的bean时出错。在文件[/home/jodo/Server/Tomcat/webapps/jodocms/WEB-INF/classes/com/jodo/cms/dao/impl/ProductTypeDaoImpl.class]中定义：bean的实例化失败;嵌套异常是org.springframework.beans.BeanInstantiationException：无法实例化bean类[com.jodo.cms.dao.impl.ProductTypeDaoImpl]：构造函数抛出异常;嵌套异常是java.lang.ClassCastException：java.lang.Class无法强制转换为java.lang.reflect.ParameterizedType
Full Stacktrace is
-------------------------------
09:24:29,443 INFO XmlWebApplicationContext:1020 - Closing Root WebApplicationContext: startup date [Tue Apr 15 08:38:10 IST 2014]; root of context hierarchy
09:24:29,445 INFO DefaultListableBeanFactory:433 - Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@153a859b: defining beans [org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.internalPersistenceAnnotationProcessor,productTypeDao,productEntityDao,productCategoryDao,categoryTreeDao,categoryEntityDao,categoryManager,productManager,dataSource,entityManagerFactory,transactionManager,org.springframework.aop.config.internalAutoProxyCreator,org.springframework.transaction.annotation.AnnotationTransactionAttributeSource#0,org.springframework.transaction.interceptor.TransactionInterceptor#0,org.springframework.transaction.config.internalTransactionAdvisor,log4jInitialization,org.springframework.context.annotation.ConfigurationClassPostProcessor$ImportAwareBeanPostProcessor#0]; root of factory hierarchy
09:24:29,460 INFO LocalContainerEntityManagerFactoryBean:441 - Closing JPA EntityManagerFactory for persistence unit 'default'
09:24:29,461 INFO SessionFactoryImpl:927 - closing
09:24:41,129 INFO DefaultListableBeanFactory:433 - Destroying singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@c27de92: defining beans [productController,categoryController,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.internalPersistenceAnnotationProcessor,org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping#0,org.springframework.format.support.FormattingConversionServiceFactoryBean#0,org.springframework.validation.beanvalidation.LocalValidatorFactoryBean#0,org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#0,org.springframework.web.servlet.handler.MappedInterceptor#0,org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver#0,org.springframework.web.servlet.mvc.annotation.ResponseStatusExceptionResolver#0,org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver#0,org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping,org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter,org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter,org.springframework.context.annotation.ConfigurationClassPostProcessor$ImportAwareBeanPostProcessor#0]; parent: org.springframework.beans.factory.support.DefaultListableBeanFactory@5803bbcc
09:24:41,134 ERROR DispatcherServlet:457 - Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.jodo.cms.service.ProductManagerService com.jodo.cms.controllers.ProductController.productManager; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productManager': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.jodo.cms.dao.ProductTypeDao com.jodo.cms.service.impl.ProductManagerServiceimpl.productTypeDao; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productTypeDao' defined in file [/home/jodo/Server/Tomcat/webapps/jodocms/WEB-INF/classes/com/jodo/cms/dao/impl/ProductTypeDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class
[com.jodo.cms.dao.impl.ProductTypeDaoImpl]: Constructor threw exception; nested exception is java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:287)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1106)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:585)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:913)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:464)
at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:631)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:588)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:645)
at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:508)
at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:449)
at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:133)
at javax.servlet.GenericServlet.init(GenericServlet.java:158)
at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1279)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1192)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1087)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5210)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5493)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:632)
at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:1073)
at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1857)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:744)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.jodo.cms.service.ProductManagerService com.jodo.cms.controllers.ProductController.productManager; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productManager': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.jodo.cms.dao.ProductTypeDao com.jodo.cms.service.impl.ProductManagerServiceimpl.productTypeDao; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productTypeDao' defined in file [/home/jodo/Server/Tomcat/webapps/jodocms/WEB-INF/classes/com/jodo/cms/dao/impl/ProductTypeDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.jodo.cms.dao.impl.ProductTypeDaoImpl]: Constructor threw exception; nested exception is java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:506)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:284)
... 33 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productManager': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.jodo.cms.dao.ProductTypeDao com.jodo.cms.service.impl.ProductManagerServiceimpl.productTypeDao; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productTypeDao' defined in file [/home/jodo/Server/Tomcat/webapps/jodocms/WEB-INF/classes/com/jodo/cms/dao/impl/ProductTypeDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.jodo.cms.dao.impl.ProductTypeDaoImpl]: Constructor threw exception; nested exception is java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:287)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1106)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:517)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:269)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:848)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:790)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:707)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:478)
... 35 more
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.jodo.cms.dao.ProductTypeDao com.jodo.cms.service.impl.ProductManagerServiceimpl.productTypeDao; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productTypeDao' defined in file [/home/jodo/Server/Tomcat/webapps/jodocms/WEB-INF/classes/com/jodo/cms/dao/impl/ProductTypeDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.jodo.cms.dao.impl.ProductTypeDaoImpl]: Constructor threw exception; nested exception is java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:506)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:284)
... 48 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productTypeDao' defined in file [/home/jodo/Server/Tomcat/webapps/jodocms/WEB-INF/classes/com/jodo/cms/dao/impl/ProductTypeDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.jodo.cms.dao.impl.ProductTypeDaoImpl]: Constructor threw exception; nested exception is java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:997)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:943)
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$1.getObject(AbstractBeanFactory.java:294)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:848)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:790)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:707)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:478)
... 50 more
Caused by: org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.jodo.cms.dao.impl.ProductTypeDaoImpl]: Constructor threw exception; nested exception is java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:162)
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:76)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:990)
... 61 more
Caused by: java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType
at com.jodo.cms.dao.impl.GenericDaoImpl.<init>(GenericDaoImpl.java:42)
at com.jodo.cms.dao.impl.ProductTypeDaoImpl.<init>(ProductTypeDaoImpl.java:19)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:147)
... 63 more
类GenericDaoImpl详细信息
public abstract class GenericDaoImpl<T extends AbstractJpaEntity> implements GenericDao<T> {
protected Class<T> entityClass;
Logger logger = Logger.getLogger(GenericDaoImpl.class);
@PersistenceContext
protected EntityManager em;
public EntityManager getEntityManager() {
return this.em;
}
@SuppressWarnings("unchecked")
public GenericDaoImpl() {
ParameterizedType genericSuperclass = (ParameterizedType) getClass().getGenericSuperclass();
this.entityClass = (Class<T>) genericSuperclass.getActualTypeArguments()[0];
}
public void persist(T entity) throws JodoException {
try {
em.persist(entity);
em.flush();
} catch (ConstraintViolationException cve) {
throw new JodoException(cve.getCause(), "constraints violated", cve);
}
}...
我无法更改AbstractJpaEntity，GenericDao和GenericDaoImpl，因为它已经用于合并许多其他未扩展ProductTypeDomain的实体。
由于
答案 0 :(得分：6)
在此课程声明中
public class ProductTypeDaoImpl extends GenericDaoImpl implements ProductTypeDao
您使用GenericDaoImpl和ProductTypeDao作为原始类型。 Start by reading why you shouldn't use them.
您使用原始类型会导致问题
ParameterizedType genericSuperclass = (ParameterizedType) getClass().getGenericSuperclass();
其中getGenericSuperclass()将返回Class以后的GenericDaoImpl个实例，
public class ProductTypeDaoImpl extends GenericDaoImpl implements ProductTypeDao
未参数化，因此不是ParameterizedType。演员随后失败了。
解决方案是在类声明中参数化两种类型。从您的代码中可以直接看出这些类型参数应该是什么，但GenericTypeDao应该采用ProductTypeDomain
public class ProductTypeDaoImpl extends GenericDaoImpl<ProductTypeDomain> implements ProductTypeDao
并且您的界面ProductTypeDao可能应该声明为
public interface ProductTypeDao extends GenericDao<ProductTypeDomain> {
答案 1 :(得分：-1)
这是一个解决方案
public TO getTo() throws Exception {
if(to == null) {
try {
to = ((Class<TO>) ((ParameterizedType) this.getClass().getGenericSuperclass())
.getActualTypeArguments()[0]).newInstance();
} catch(ClassCastException cce) {
cce.printStackTrace();
to = ((Class<TO>) ((ParameterizedType) (((Class<TO>) this.getClass()
.getAnnotatedSuperclass().getType()).getGenericSuperclass()))
.getActualTypeArguments()[0]).newInstance();
}
}
return to;
}