Spring AOP，声明父母强制转换异常

问题描述

我有:

• 接口GenericDao
• 类GenericDaoImpl实现GenericDao
• 类UserDao

• an interface GenericDao
• a class GenericDaoImpl implements GenericDao
• a class UserDao

UserDao userDao;
public void setUserDao(UserDao val) { userDao = val; }
...
((GenericDao) userDao).update(user);

---

我的Beans.xml看起来像:

---

My Beans.xml looks like:

<bean id="genericUserDao" class="dao.GenericDaoImpl">
  ...
  <property name="sessionFactory" ref="hibernateSessionFactory" />
</bean>

<bean id="userDao" class="dao.user.UserDao">
  <property name="sessionFactory" ref="hibernateSessionFactory" />
</bean>

<aop:config>
  <aop:aspect>
    <aop:declare-parents
            types-matching="dao.user.UserDao"
            implement-interface="dao.GenericDao"
            default-impl="genericUserDao" />
  </aop:aspect>
</aop:config>

这是导致

java.lang.ClassCastException: dao.user.UserDao cannot be cast to dao.GenericDao

我还尝试将default-impl设置为:dao.user.UserDao，但结果相同.

I also tried setting default-impl to: dao.user.UserDao but result is the same.

我找不到任何好的文档或示例来说明正确的xml配置.

I couldn't find any good documentation or examples showing proper xml configuration.

我的XML有什么问题?

What is wrong with my XML?

这里是完整的错误堆栈:

Here is full error stack:

Exception in thread "Thread-3" java.lang.ClassCastException: dao.user.UserDao cannot be cast to dao.GenericDao
    at dao.GenericDao$$FastClassBySpringCGLIB$$d43da5ef.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:717)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
    at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:133)
    at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:121)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:653)
    at dao.user.UserDao$$EnhancerBySpringCGLIB$$957148da.update(<generated>)

推荐答案

我找到了解决方案.

  <aop:config>
    <aop:aspect>
      <aop:declare-parents
              types-matching="dao.user.UserDao+"
              implement-interface="dao.GenericDao"
              delegate-ref="genericUserDao" />
    </aop:aspect>
  </aop:config>

需要在类型匹配中添加加号(+)，并将default-impl更改为委托引用.

Needed to add plus sign (+) to types-matching and change default-impl to delegate-ref.

这篇关于Spring AOP，声明父母强制转换异常的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！