找到了一个解决方案。文件spring.schemas将https://www.springframework.org/schema/security/spring-security-oauth2-2.0.xsd链接到spring-security-oauth2.jar中的spring-security-oauth2-2.0.xsd。该文件在解析Spring XML配置时使用。
因此，您只需将架构位置设置为https URL：
https://www.springframework.org/schema/security/spring-security-oauth2-2.0.xsd
而不是http URL：
http://www.springframework.org/schema/security/spring-security-oauth2-2.0.xsd
在XML配置文件中。
就像这个例子中的最后两行：

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:oauth="http://www.springframework.org/schema/security/oauth2"
       xmlns:sec="http://www.springframework.org/schema/security"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans-4.1.xsd
       http://www.springframework.org/schema/security
       http://www.springframework.org/schema/security/spring-security-3.2.xsd
       http://www.springframework.org/schema/security/oauth2
       https://www.springframework.org/schema/security/spring-security-oauth2-2.0.xsd">