java.lang.ClassNotFoundException : com. springhibernatemvc.dao.PersonDAOImpl

Question

我的 servlet-context.xml 中出现错误。据说可以找到以下类，但实际上存在于project文件夹中。

<beans:bean id="personDAO" class="com.springhibernatemvc.dao.PersonDAOImpl">
        <beans:property name="sessionFactory" ref="hibernate4AnnotatedSessionFactory" />
    </beans:bean>
    <beans:bean id="personService" class="com.springbibernate.services.PersonServiceImpl">
        <beans:property name="personDAO" ref="personDAO"></beans:property>
    </beans:bean>

它说找不到这个类

- Class 'com.springbibernate.services.PersonServiceImpl' 

我的 servlet-context 文件也在我的 web.xml 文件中定义

<servlet>
        <servlet-name>appServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/spring/appServlet/servlet-context.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

我已将 servlet-context.xml 添加到我的 Web 应用程序的根文件夹中，但错误仍然存​​在。

完整的堆栈跟踪

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping#0': Invocation of init method failed; nested exception is org.springframework.beans.factory.CannotLoadBeanClassException: Cannot find class [com.springhibernatemvc.dao.PersonDAOImpl] for bean with name 'personDAO' defined in ServletContext resource [/WEB-INF/spring/appServlet/servlet-context.xml]; nested exception is java.lang.ClassNotFoundException: com.springhibernatemvc.dao.PersonDAOImpl
Related cause: org.springframework.beans.factory.CannotLoadBeanClassException: Cannot find class [com.springhibernatemvc.dao.PersonDAOImpl] for bean with name 'personDAO' defined in ServletContext resource [/WEB-INF/spring/appServlet/servlet-context.xml]; nested exception is java.lang.ClassNotFoundException: com.springhibernatemvc.dao.PersonDAOImpl

可能出了什么问题？

Answer 1

来自 Java 文档

Thrown when an application tries to load in a class through its string name using:

• The forName method in class Class.
• The findSystemClass method in class ClassLoader .
• The loadClass method in class ClassLoader.

but no definition for the class with the specified name could be found.

这里的问题不在于servlet-context.xml，而在于其中定义的bean。确保完整的规范类名正确，并且相应的类文件存在于 WEB-INF 或该目录下的某个库下。

从第一个高层次来看，您似乎将 class 的 bean 定义为 'com.springbibernate.services.PersonServiceImpl'

其中正确的名称似乎是“com.springhibernate.services.PersonServiceImpl”

所以 xml 内容应该是这样的:

<beans:bean id="personDAO" class="com.springhibernatemvc.dao.PersonDAOImpl">
        <beans:property name="sessionFactory" ref="hibernate4AnnotatedSessionFactory" />
    </beans:bean>
    <beans:bean id="personService" class="com.springhibernate.services.PersonServiceImpl">
        <beans:property name="personDAO" ref="personDAO"></beans:property>
    </beans:bean>