In Spring, the inheritance is supported in bean configuration for a bean to share common values, properties or configurations.
A child bean or inherited bean can inherit its parent bean configurations, properties and some attributes. In additional, the child beans are allow to override the inherited value.
例子如下：
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public class Customer {
private int type;
private String action;
private String Country;
//...
} |
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<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean id="BaseCustomerMalaysia" class="com.mkyong.common.Customer">
<property name="country" value="Malaysia" />
</bean>
<bean id="CustomerBean" parent="BaseCustomerMalaysia">
<property name="action" value="buy" />
<property name="type" value="1" />
</bean>
</beans>
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public class App{ public static void main( String[] args )
{
ApplicationContext context =
new ClassPathXmlApplicationContext("SpringBeans.xml");
Customer cust = (Customer)context.getBean("CustomerBean");
System.out.println(cust);
}
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运行结果为：Customer [type=1, action=buy, Country=Malaysia]
In above example, the ‘BaseCustomerMalaysia’ is still able to instantiate, for example,
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Customer cust = (Customer)context.getBean("BaseCustomerMalaysia");
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类似于java的抽象类，我们可以有：(注意abstract="true")
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<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean id="BaseCustomerMalaysia" class="com.mkyong.common.Customer" abstract="true">
<property name="country" value="Malaysia" />
</bean>
<bean id="CustomerBean" parent="BaseCustomerMalaysia">
<property name="action" value="buy" />
<property name="type" value="1" />
</bean>
</beans>
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现在当你运行：
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Customer cust = (Customer)context.getBean("BaseCustomerMalaysia");
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将会出现：
org.springframework.beans.factory.BeanIsAbstractException: Error creating bean with name 'BaseCustomerMalaysia': Bean definition is abstract
Pure Inheritance Template
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<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean id="BaseCustomerMalaysia" abstract="true">
<property name="country" value="Malaysia" />
</bean>
<bean id="CustomerBean" parent="BaseCustomerMalaysia"
class="com.mkyong.common.Customer">
<property name="action" value="buy" />
<property name="type" value="1" />
</bean>
</beans>
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也可以重写值：
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<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean id="BaseCustomerMalaysia" class="com.mkyong.common.Customer" abstract="true">
<property name="country" value="Malaysia" />
</bean>
<bean id="CustomerBean" parent="BaseCustomerMalaysia">
<property name="country" value="Japan" />
<property name="action" value="buy" />
<property name="type" value="1" />
</bean>
</beans>
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==============================================================================
本文转自被遗忘的博客园博客，原文链接：http://www.cnblogs.com/rollenholt/archive/2012/12/27/2835130.html，如需转载请自行联系原作者