1、构造函数
<bean id="accountService" class="com.itheima.service.impl.AccountServiceImpl">
2、普通方法
<bean id="instanceFactory" class="com.itheima.factory.InstanceFactory">
<bean id="accountService" factory-bean="instanceFactory" factory-method="getAccountService">
3、静态方法
<bean id="accountService" class="com.itheima.factory.StaticFactory" factory-method="getAccountService">