SSH构架的java系统,换数据库后,如何配置才能不重新新建表结构

SSH构架的java系统,换数据库后,怎么配置才能不重新新建表结构?
hibernate是交给spring来管理的.
大家帮我一下
怎么配置spring上的属性呢

------解决方案--------------------
applicationContext.xml(/WEB-INF/applicationContext.xml)

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN" "http://www.springframework.org/dtd/spring-beans-2.0.dtd">

<beans>
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="org.gjt.mm.mysql.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/stud"/>
<property name="username" value="root" />
<property name="password" value="root" />
</bean> 
<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
<prop key="hibernate.show_sql">true</prop>
</props>
</property>
<property name="mappingResources">
<list>
<value>com/ex/model/Employee.hbm.xml</value>
</list>
</property>
</bean>
 
 <bean id="employeeDao" class="com.ex.dao.impl.EmployeeDaoImpl">
<property name="sessionFactory" ref="sessionFactory" />
 </bean>

 <bean id="employeeManager" class="com.ex.service.impl.EmployeeManagerImpl">
<property name="employeeDao" ref="employeeDao" />
 </bean>
 
 <bean id="addBean" class="com.ex.action.EmployeeAction" scope="prototype">
<property name="employeeManager" ref="employeeManager" />
 </bean>

 <bean id="editBean" class="com.ex.action.EmployeeAction" scope="prototype">
<property name="employeeManager" ref="employeeManager" />
 </bean>
 
 <bean id="updateBean" class="com.ex.action.EmployeeAction" scope="prototype">
<property name="employeeManager" ref="employeeManager" />
 </bean>
  
 <bean id="deleteBean" class="com.ex.action.EmployeeAction" scope="prototype">
<property name="employeeManager" ref="employeeManager" />
 </bean>
 
 <bean id="saveOrUpdateBean" class="com.ex.action.EmployeeAction" scope="prototype">
<property name="employeeManager" ref="employeeManager" />
 </bean>
 
 <bean id="listBean" class="com.ex.action.EmployeeAction" scope="prototype"> 
<property name="employeeManager" ref="employeeManager" />
 </bean> 

 <bean id="loginBean" class="com.ex.action.EmployeeAction" scope="prototype">
<property name="employeeManager" ref="employeeManager" />
 </bean>
 
 

</beans>

------解决方案--------------------