关于list<Pen> 注入对象问题；

public class Pen {
    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

相关代码：

public class SchoolBag {
    private String color;
    private List<Pen> pencilCase;

    public SchoolBag() {
    }

    public SchoolBag(String color, List<Pen> pencilCase) {
        this.color = color;
        this.pencilCase = pencilCase;
    }

    public String getColor() {
        return color;
    }

    public void setColor(String color) {
        this.color = color;
    }

    public List<Pen> getPencilCase() {
        return pencilCase;
    }

    public void setPencilCase(List<Pen> pencilCase) {
        this.pencilCase = pencilCase;
    }
}

相关代码：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                      http://www.springframework.org/schema/beans/spring-beans.xsd">


    <bean id="redSchoolBag" class="com.acumen.spring.ioc.entity.SchoolBag">
        <property name="color" value="红色"/>
        <property name="pencilCase">
            <list>
               <bean class="com.acumen.spring.ioc.entity.Pen">
                   <property name="name" value="2B铅笔"/>
               </bean>
                <bean class="com.acumen.spring.ioc.entity.Pen">
                    <property name="name" value="2H铅笔"/>
                </bean>
                <bean class="com.acumen.spring.ioc.entity.Pen">
                    <property name="name" value="钢笔"/>
                </bean>
            </list>
        </property>
    </bean>
</beans>

问题描述：

几乎是自己乱摸索出来的；List<Pen> 还有啥方法注入对象？

我看其他同学可以通过<list><value>钢笔</value><list>赋值，到我这来就一直报错？