So old version:
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:security="http://www.springframework.org/schema/security" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.0.xsd"> <security:http auto-config="true" use-expressions="true"> .... </security:http> </beans>
And new version:
<beans:beans xmlns:beans="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/security" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.0.xsd"> <http auto-config="true" use-expressions="true"> .... </http> </beans:beans>
One thing I don't understand is why change beans to beans:beans. Why does the top element need a namespace?
Then I try to remove the namespace, the XML complains "Cannot find the declaration of element 'beans'".
Well, after reading the article XML Schema: Understanding Namespaces, I come to understand that the scope of a namespace begins at the element where it is declared. Therefore, in the old version, the element beans is associated with the default namespace (http://www.springframework.org/schema/beans), in the new version, if we remove the namespace for the beans element, the element will be associated with the security namespace. But of course, the security schema doesn't define a beans element. Hence the complaint of the XML.
Let me rename the prefix of the beans namespace so that it looks more clear.
<bean123:beans xmlns:bean123="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/security" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.0.xsd"> <http auto-config="true" use-expressions="true"> .... </http> </bean123:beans>
