Spring AOP配置文件

Multiple annotations found at this line:
- cvc-complex-type.2.4.c: The matching wildcard is strict, but no declaration can be found for element 'aop:aspectj-autoproxy'.
- schema_reference.4: Failed to read schema document 'http://www.springframework.org/schema/aop/spring-aop-3.0.xsd', because 1) could not find the
document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.

　　http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd[/code] 
　　有个小疑问，为啥加入之后，再删掉代码。又不会报错！？？？