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java.lang.ClassCastException: com.sun.proxy.$Proxy13 cannot be cast to sm.dao.UserDao

2024-08-10 04:35:20   219人阅读

在Spring中添加事物管理以后出现的问题

源代码

ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");UserDao userDao = (UserDao) applicationContext.getBean("UserDao");

 错误原因对于Spring AOP 采用两种代理方法，一种是常规JDK，一种是CGLIB，我的UserDao了一个接口IUserDao，当代理对象实现了至少一个接口时，默认使用JDK动态创建代理对象，当代理对象没有实现任何接口时，就会使用CGLIB方法。具体介绍文章 

解决方法：

因为基于JDK的代理是面向接口的，所以我们自己修改代码如下

   ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");    IUserDao userDao = (IUserDao) applicationContext.getBean("UserDao");

附上applicationContext.xml配置

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:jdbc="http://www.springframework.org/schema/jdbc"       xmlns:tx="http://www.springframework.org/schema/tx"       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">    <bean id="dataSoure" class="org.apache.commons.dbcp.BasicDataSource">        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>        <property name="url" value="jdbc:mysql://localhost:3306/sm"></property>        <property name="username" value="root"></property>        <property name="password" value="genji"></property>    </bean>    <bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">        <property name="dataSource">            <ref bean="dataSoure"></ref>        </property>        <property name="hibernateProperties">            <props>                <prop key="hibernate.dialect">                    org.hibernate.dialect.MySQL5Dialect                </prop>                <prop key="hibernate.current_session_context_class">                    org.springframework.orm.hibernate4.SpringSessionContext                </prop>            </props>        </property>        <property name="mappingResources">            <list>                <value>sm/po/Studentinfo.hbm.xml</value>                <value>sm/po/User.hbm.xml</value>            </list>        </property>    </bean>    <bean id="UserDao" class="sm.dao.UserDao">        <property name="sessionFactory">            <ref bean="sessionFactory"></ref>        </property>    </bean>    <bean id="SinfoDao" class="sm.dao.SinfoDao">        <property name="sessionFactory">            <ref bean="sessionFactory"></ref>        </property>    </bean>
//就是在这里实现了事务代理
    <bean id="txManager"          class="org.springframework.orm.hibernate4.HibernateTransactionManager">        <property name="sessionFactory" ref="sessionFactory" />    </bean>    <tx:annotation-driven />    <tx:advice id="txAdvice" transaction-manager="txManager">        <tx:attributes>            <tx:method name="add" read-only="true" propagation="REQUIRED" />            <tx:method name="read" propagation="REQUIRED" />            <tx:method name="del" propagation="REQUIRED" />            <tx:method name="mod" propagation="REQUIRED" />            <tx:method name="sameId" propagation="REQUIRED" />            <tx:method name="findUser" propagation="REQUIRED"/>            <tx:method name="addUser" propagation="REQUIRED"></tx:method>        </tx:attributes>    </tx:advice></beans>

 相关文章

http://cheneyjuu.blog.163.com/blog/static/41917640201051042941159/

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java.lang.ClassCastException: com.sun.proxy.$Proxy13 cannot be cast to sm.dao.UserDao


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