多个xmlns 为毛只有一个xsd约束？？

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd">

<bean name="john-classic" class="com.example.Person">
    <property name="name" value="John Doe"/>
    <property name="spouse" ref="jane"/>
</bean>

<bean name="john-modern"
    class="com.example.Person"
    p:name="John Doe"
    p:spouse-ref="jane"/>

<bean name="jane" class="com.example.Person">
    <property name="name" value="Jane Doe"/>
</bean>

http://www.springframework.org/schema/beans
http://www.springframework.org/schema/p
这两个约束 只有beans有 p没有约束的吗？？ p的xsd在哪里的

https://blog.csdn.net/dingqinghu/article/details/46758671