spring提供了filed的值注入和method的返回值注入。
1、Field值的注入
filed值注入需要使用org.springframework.beans.factory.config.FieldRetrievingFactoryBean来获取类的静态变量。
例如，我们通常在接口中定义常量：
view plaincopy to clipboardprint?package com.baobaotao.fb;
public interface CarBrandType {
String HONG_QI = "红旗";
String JI_LI = "吉利";
}
package com.baobaotao.fb;
public interface CarBrandType {
String HONG_QI = "红旗";
String JI_LI = "吉利";
}
下面利用FieldRetrievingFactoryBean获取CarBandType接口中定义的常量，并注入到某个bean的属性中：
view plaincopy to clipboardprint?<bean id="car" class="com.baobaotao.fb.Car">
<property name="brand" ref="hongQi"/>
</bean>
<bean id="hongQi" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean"
<property name="staticField" value="com.baobaotao.fb.CarBrandType.HONG_QI"/>
</bean>
<bean id="car" class="com.baobaotao.fb.Car">
<property name="brand" ref="hongQi"/>
</bean>
<bean id="hongQi" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean"
<property name="staticField" value="com.baobaotao.fb.CarBrandType.HONG_QI"/>
</bean>
Spring还允许用户用常量的全限定名作为FieldRetrievingFactoryBean的id，其效果和通过配置staticField属性是一样的：
view plaincopy to clipboardprint?<bean id="car" class="com.baobaotao.fb.Car">
<property name="brand" ref="com.baobaotao.fb.CarBrandType.HONG_QI"/>
</bean>
<bean id="com.baobaotao.fb.CarBrandType.HONG_QI" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean" />
<bean id="car" class="com.baobaotao.fb.Car">
<property name="brand" ref="com.baobaotao.fb.CarBrandType.HONG_QI"/>
</bean>
<bean id="com.baobaotao.fb.CarBrandType.HONG_QI" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean" />
当然，也可以直接将FieldRetrievingFactoryBean以内置bean的方式对brand属性进行赋值，这样在配置上更紧凑一些：
view plaincopy to clipboardprint?<bean id="car" class="com.baobaotao.fb.Car">
<property name="brand">
<bean id="com.baobaotao.fb.CarBrandType.HONG_QI" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean">
</bean>
</property>
</bean>
<bean id="car" class="com.baobaotao.fb.Car">
<property name="brand">
<bean id="com.baobaotao.fb.CarBrandType.HONG_QI" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean">
</bean>
</property>
</bean>
2、Method返回值的注入
Method返回值的注入需要使用MethodInvokingFactoryBean来完成。
在xml配置中，需要设定targetObject和targetMethod来指定目标bean和方法。如果使用静态方法，则需要指定targetClass和targetMethod
配置文件如下：
view plaincopy to clipboardprint?<bean id="bdog" class="com.baobaotao.fb.Dog">
<property name="age">
<bean class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
<property name="targetObject">
<ref local="randomAge"/>
</property>
<property name="targetMethod">
<value>getAge</value>
</property>
</bean>
</property>
</bean>
<bean id="randomAge" class="com.baobaotao.fd.RandomAge" />
<bean id="bdog" class="com.baobaotao.fb.Dog">
<property name="age">
<bean class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
<property name="targetObject">
<ref local="randomAge"/>
</property>
<property name="targetMethod">
<value>getAge</value>
</property>
</bean>
</property>
</bean>
<bean id="randomAge" class="com.baobaotao.fd.RandomAge" />
对于静态方法：
view plaincopy to clipboardprint?<bean id="bdog" class="com.baobaotao.fb.Dog">
<property name="age">
<bean class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
<property name="targetClass">
<value>com.baobaotao.fb.RandomAge</value>
</property>
<property name="targetMethod">
<!-- getAge必须是静态方法 -->
<value>getAges</value>
</property>
</bean>
</property>
</bean>