<bean id="mappings"
    class="...">
    <property name="properties">
        <value>
            name=jianglei
            love=dengyi
            age=18
        </value>
    </property>
</bean>

Spring容器会把<value/>内置的文本转换为java.util.Properties实例通过使用PropertyEditor机制。

The idref element

<bean id="theTargetBean" class="..."/>

<bean id="theClientBean" class="..."/>
    <property name="targetName">
        <idref bean=theTargetBean"/>
    </property>
</bean>

等价于

<bean id="theTargetBean" class="..." />

<bean id="client" class="...">
    <property name="targetName" value="theTargetBean"/>
</bean>

idref引用bean的名字,如果引用的bean的名字不存在会抛出异常

Inner beans

<bean id="outer" class="...">
    <property name="target">
        <bean class="com.example.Person">
            <property name="name" value="Fiona Apple/>
            <property name="age" value="25"/>
        <bean>
    </property>
</bean>

内置bean不需要id或者name;如果指定了，容器也不会使用此值作为标识符。容器在创建时也会忽略scope。

内置的bean永远是匿名的，他永远由外部bean创建。

内置的bean不能注入到别的

？？？

As a corner case, it is possible to receive destruction callbacks from a custom scope, e.g. for a request-scoped inner bean contained within a singleton bean: The creation of the inner bean instance will be tied to its containing bean, but destruction callbacks allow it to participate in the request scope’s lifecycle. This is not a common scenario; inner beans typically simply share their containing bean’s scope.

集合

<list/> <set/> <map/> <props/> 元素

对应

List, Set, Map 和 Properties

<bean id="moreComplexObject" class="example.ComplexObject">
    <property name="adminEmails">
        <props>
            <prop key="admin>[email protected]</prop>
            <prop key="support">[email protected]</prop>
            <prop key="dev">[email protected]</prop>
        </props>
    </property>

    <property name="someList">
        <list>
            <value>a list element followed by a reference</value>
            <ref bean="myDataSource"/>
        </list>
    </property>

    <property name="someMap">
        <map>
            <entry key="an entry" value="just some string"/>
            <entry key="a ref" value-ref="myDataSource"/>
        </map>
    </property>

    <property name="someSet">
        <set>
            <value>just some string</value>
            <ref bean="myDataSource" />
        </set>
    </property>
</bean>

map的键和值 或者set的值可以是下列元素中的任何一个

bean | ref | idref | list | set | map | props | value | null

集合合并

<list/>, <map/>, <set/> 或者 <props/>元素可以支持合并

<beans>
    <bean id="parent" abstract="true" class="example.ComplexObject">
        <property name="adminEmails">
            <props>
                <prop key="admin">[email protected]</prop>
                <prop key="support">[email protected]</prop>
            </props>
        </property>
    <bean>
    <bean id="child" parent="parent">
        <property name="adminEmails>
            <props merge="true">
                <prop key="sales">[email protected]</prop>
                <prop key="support">[email protected]</prop>
            </props>
        </property>
</beans>

集合合并的限制

你不能合并两种不同类型的集合（比如Map和List)，如果你这么做了将会抛出相应的异常。

merge属性必须在继承的子bean中定义。定义在父bean的集合属性上指定的merge属性是多余的并且得不到期望的合并结果

强类型集合（泛型集合）

public class Foo{
    private Map<String, Float> accounts;

    public void setAccount(Map<String, Float> accounts){
        this.accounts = accounts;
    }
}

<beans>
    <bean id="foo" class="x.y.Foo">
        <property name="accounts">
            <map>
                <entry key="one" value="9.99"/>
                <entry key="two" value="2.75"/>
                <entry key="six" value="3.99/>
            </map>
        </property>
    </bean>
</beans>

容器会获取属性的泛型信息，并把相应的值转换为相应的类型。如果类型不一致，则会抛出异常

Null 和 空字符串

空字符串

<bean class="ExampleBean">
    <property name="email" value=""/>
</bean>

等价于

exampleBean.setEmail("")

null值

<bean class="ExampleBean">
    <property name="email">
        <null/>
    </property>
</bean>

等价于

exampleBean.setEmail(null)