spring 约束详解

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    //上面两个是基础IOC的约束，必备
    xmlns:context="http://www.springframework.org/schema/context"
    //上面一个是开启注解管理Bean对象的约束
    xmlns:aop="http://www.springframework.org/schema/aop"
    //aop的注解约束
    xmlns:tx="http://www.springframework.org/schema/tx"
    //事务的约束
    xsi:schemaLocation="http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans.xsd
    //上面两个是基础IOC的约束，必备
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context.xsd
    //上面一个是开启注解管理Bean对象的约束
    http://www.springframework.org/schema/aop
    http://www.springframework.org/schema/aop/spring-aop.xsd
    //aop的注解约束
    http://www.springframework.org/schema/tx
    http://www.springframework.org/schema/tx/spring-tx.xsd">
    //事务的约束
</beans>