1. 案例环境

@Data
public class Car {
    private String name;
    private Double price;
}

@Data
public class Person {
    private Car car;
    private Object[] arr;
}

2. 内部Bean不可获取

内部Bean不可获取，只供内部使用，外部不能获取。因此内部Bean设置id是没有意义的，相当于没有设置

2.1. 测试从容器中取出内部Bean

<bean id="person" class="bean.Person">
    <property name="car">
        <bean id="carInner" class="bean.Car">
            <property name="name" value="carInner" />
            <property name="price" value="5000.0" />
        </bean>
    </property>
</bean>

@Test
public void testIoc() throws Exception {
    ApplicationContext ioc = new ClassPathXmlApplicationContext("applicationContext.xml");
    Car car = (Car) ioc.getBean("carInner");
    System.out.println(car);
}

运行，抛出异常。虽然定义了内部Bean，并设置了ID，但是根据ID获取内部Bean时，还是提示Bean没有定义（注册）过，因此可知内部Bean是无法获取的

1	org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'carInner' available

2.2. 测试使用ref引用内部Bean

<bean id="person" class="bean.Person">
    <property name="car">
        <bean id="carInner" class="bean.Car">
            <property name="name" value="carInner" />
            <property name="price" value="5000.0" />
        </bean>
    </property>
    <property name="arr">
       <array>
           <!-- ref引用内部Bean -->
           <ref bean="carInner"/>
       </array>
    </property>
</bean>

@Test
public void testIoc() throws Exception {
    ApplicationContext ioc = new ClassPathXmlApplicationContext("applicationContext.xml");
    Person person = ioc.getBean(Person.class);
    System.out.println(person);
}

运行，也是提示Bean没有定义

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'person' defined in class path resource [applicationContext.xml]: Cannot resolve reference to bean 'carInner' while setting bean property 'arr' with key [0]; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'carInner' available