如何在Spring4中创建PropertySourcesPropertyResolver的子类？

public class CustomPropertyResolver extends PropertySourcesPropertyResolver {
    // 实现自定义的逻辑
}

public class CustomPropertyResolver extends PropertySourcesPropertyResolver {
    
    public CustomPropertyResolver(PropertySources propertySources) {
        super(propertySources);
    }
    
    // 实现自定义的逻辑
}

public class CustomPropertyResolver extends PropertySourcesPropertyResolver {
    
    public CustomPropertyResolver(PropertySources propertySources) {
        super(propertySources);
    }
    
    @Override
    public String getProperty(String key) {
        // 自定义逻辑
        // 返回指定key对应的属性值
    }
    
    // 实现其他自定义的方法
}

<bean id="propertyResolver" class="com.example.CustomPropertyResolver">
    <constructor-arg ref="propertySources" />
</bean>