这课我们来讲自动装配，或者叫自动注入，Autowired
Spring容器可以自动装配协作bean之间的关系。不扯淡，直接看代码
autowire属性的几个可选值:
default: 就是no
byName: 根据属性名称使用getBean(String name)方法装配bean
byType: 根据属性类型使用getBean(Class reuiredType)方法装配bean
constructor: 根据该类的构造器自动装配bean
no: 默认值，不进行自动装配
byName
<bean id="father" class="com.ioc.bean.Father"> <property name="name" value="父亲"></property> </bean> <bean id="mother" class="com.ioc.bean.Mother"> <property name="name" value="母亲"></property> </bean> <bean id="child" class="com.ioc.bean.Daughtor"> <property name="name" value="女儿"></property> </bean> <!--<bean id="child2" class="com.ioc.bean.Son">--> <!--<property name="name" value="儿子"></property>--> <!--</bean>--> <!-- public class Family { private Father father; private Mother mother; private Child child; } 可以看到Family各个属性的名字和上面的bean的id一样，所以可以自动装配成功 当getBean(String name)无法匹配到合适的bean时就会返回null，这时Family的child属性就为null了 --> <bean id="family" class="com.ioc.bean.Family" autowire="default"> </bean>
byType
<bean id="father" class="com.ioc.bean.Father"> <property name="name" value="父亲"></property> </bean> <bean id="mother" class="com.ioc.bean.Mother"> <property name="name" value="母亲"></property> </bean> <bean id="child1" class="com.ioc.bean.Daughtor"> <property name="name" value="女儿"></property> </bean> <bean id="child2" class="com.ioc.bean.Son"> <property name="name" value="儿子"></property> </bean>
<!-- public class Family { private Father father; private Mother mother; private Child child; } byType则直接根据属性的类型进行匹配,但如果根据类型匹配到多个bean则会抛出异常 --> <bean id="family" class="com.ioc.bean.Family" autowire="default"> </bean>
no和default
<bean id="father" class="com.ioc.bean.Father"> <property name="name" value="父亲"></property> </bean> <bean id="mother" class="com.ioc.bean.Mother"> <property name="name" value="母亲"></property> </bean> <bean id="child1" class="com.ioc.bean.Daughtor"> <property name="name" value="女儿"></property> </bean> <bean id="child2" class="com.ioc.bean.Son"> <property name="name" value="儿子"></property> </bean>
<!--
public class Family {
private Father father;
private Mother mother;
private Child child;
}
no就是不进行自动装配 default也是no
--> <bean id="family" class="com.ioc.bean.Family" autowire="no"> </bean>
constructor一般不用
