spring security配置，web.xml顺序问题

今天在学习spring security时遇到一个问题：

        <context-param>
                <param-name>contextConfigLocation</param-name>
		<param-value>
			/WEB-INF/classes/JDBC-context.xml
			/WEB-INF/classes/spring-security.xml 
		</param-value>
       </context-param>

security配置文件spring-security.xml放在后面时报错：

org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [com.spring.security.IChangePassword] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

而将配置文件spring-security.xml放在前面时则正常。