Spring注入bean失败Failed to convert property value of type 不指定

Heck post in Web开发 2014/03/28 00:36 评论(0) 阅读(737) | |
Failed to convert property value of type [$Proxy13
Failed to convert property value of type [$Proxy13] to required type

PropertyAccessException 1: org.springframework.beans.TypeMismatchException: Failed to convert property value of type [$Proxy13] to required type [tk.hecks.dao.AuthorDaoImp] for property 'authorDaoImp'; nested exception is java.lang.IllegalArgumentException: Cannot convert value of type [$Proxy13] to required type [tk.hecks.dao.AuthorDaoImp] for property 'authorDaoImp': no matching editors or conversion strategy found  
Caused by:  
org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessException details (1) are:  
PropertyAccessException 1:  
org.springframework.beans.TypeMismatchException: Failed to convert property value of type [$Proxy13] to required type [tk.hecks.dao.AuthorDaoImp] for property 'authorDaoImp'; nested exception is java.lang.IllegalArgumentException: Cannot convert value of type [$Proxy13] to required type [tk.hecks.dao.AuthorDaoImp] for property 'authorDaoImp': no matching editors or conversion strategy found  
Caused by:  
java.lang.IllegalArgumentException: Cannot convert value of type [$Proxy13] to required type [tk.hecks.dao.AuthorDaoImp] for property 'authorDaoImp': no matching editors or conversion strategy found  
at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:231)  
at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:138)  
at org.springframework.beans.BeanWrapperImpl.setPropertyValue(BeanWrapperImpl.java:815)

当系统出现类似上面的异常信息时,很可能你引用了已经实现了自动代理的Bean,  Cannot convert value of type [$Proxy13] to required type [tk.hecks.dao.AuthorDaoImp] for property 'authorDaoImp' 提示的意思:你将authorDaoImp注入到一个spring受管Bean中,  但是spring容器提示你注入的Bean类型不对,它说你注入的是 [$Proxy13] 类型,这就说明你可能在无意中将authorDaoImp实现了代理, 此时你再在spring容器中引用 authorDaoImp时得到的将是代理类型。示例如下(在数据源,事务管理器配置完整的前提下):

<bean id="authorDaoImp" class="tk.hecks.dao.AuthorDaoImp">  
          <property name="hibernateTemplate">  
                  <ref bean="hibernateTemplate"/>  
          </property>  
    </bean>  
      
    <bean id="userLoginBo" class="tk.hecks.bo.UserLoginBo">  
<property name="authorDaoImp">  
                  <ref bean="authorDaoImp"/>  
           </property>

          
    </bean>  
    
         <!-- 配置事务管理器 -->
       <bean id="transactionManager"  class="org.springframework.orm.hibernate3.HibernateTransactionManager">  
          <property name="sessionFactory" ref="sessionFactory"/>  
       </bean>  
        
      
       <!-- 配置事务拦截bean -->
       <bean id="transactionInterceptor"  class="org.springframework.transaction.interceptor.TransactionInterceptor">

       <!-- 事务拦截bean需要注入一个事务管理器 -->
             <property name="transactionManager" ref="transactionManager"/>  
             <property name="transactionAttributes">  
                   <props>  
                       <prop key="insert*">PROPAGATION_REQUIRED</prop>  
                       <prop key="find*">PROPAGATION_REQUIRED</prop>  
                       <prop key="add*">PROPAGATION_REQUIRED</prop>  
                        <prop key="save">PROPAGATION_REQUIRED</prop>  
                        <prop key="Print*">PROPAGATION_REQUIRED</prop>  
                   </props>  
             </property>  
       </bean>  
      
        <bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">    
                <property name="beanNames">  
                    <value>validateUserBean,authorDaoImp</value>  
                </property>  
                <property name="interceptorNames">    
                        <list>    
                                <value>transactionInterceptor</value>    
                                <!--    
                                此处增加新的Interceptor  
                                -->    
                        </list>    
                </property>    
        </bean>    
      

上面红色显示的authorDaoImp对象注入给了userLoginBo受管Bean, 但是下面的配置中spring为authorDaoImp生成了自动代理,所以在上面的注入中注入的将是代理对象(提示信息中的 [$Proxy13] )而不是原来的authorDaoImp对象,这就产生了上面错误信息。

这种异常根据其产生的原因可以用下面二种方法解决:
如果异常产生原因是你将代理Bean注入给了其它受管Bean
1. 将自动生成代理的authorDaoImp的配置去掉.
2. 在接受注入的Bean中,将注入Bean类型改为它的接口类型.
3.不要将自动生成了代理的Bean注入给其它受管Bean.
如果异常产生原因是使用getBean("")方法产生时
2.不获得自动生成了代理的Bean.
3 . 在使用XXX.getBean("")方法得到生成了自动代理的受管Bean时, 使用它的接口为其造型.

来源:Heck's Blog
地址:http://www.hecks.tk/post/419/
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