Spring AOP 创建额外的 bean [英] Spring AOP creates extra bean
问题描述
我在玩 Spring AOP.
I 'm playing with Spring AOP.
这是一个简单的类
public class CModel extends Car {
private double torqueMeasure = 1;
public CModel() {
System.out.println(" C-Model constructor");
}
}
而Spring的配置是这样的
And Spring configuration is like this
<aop:config>
<aop:aspect ref="audit">
<aop:before pointcut="execution(* com.test.main..*(..))" method="firstControl"/>
...
</aop:aspect>
</aop:config>
现在好了;当我添加 aop:config 并拦截 CModel 时,Spring 会调用 CModel 构造函数两次.这意味着 Spring 创建了 2 个 CModel 对象,对吗?
Ok now; when i add aop:config and intercepts CModel then Spring calls CModel constructor twice. It means Spring creates 2 CModel object, right ?
如果我删除 AOP 配置,那么 Spring 只会创建一个 CModel 对象.
If I delete AOP config then Spring creates only one CModel object.
知道为什么会这样吗?
谢谢.
推荐答案
虽然我不确定,但我的猜测是 spring 先实例化常规类,然后再做一个 CGLIB 代理,它是一个子类.注意初始化应该使用@PostConstruct
,保证使用一次.
Though I'm not sure, my guess is that spring first instantiates the regular class, and then makes a CGLIB proxy, which is a subclass. Note that for initialization you should use @PostConstruct
, which is guaranteed to be used once.
为了验证我的假设,在构造函数中添加一个断点并查看它何时被调用 - 有一次它应该在 CModel$EnhancedByCGLIB
之后
To verify my hypothesis, add a breakpoint in the constructor and see when it is invoked - one of the times it should be right after the CModel$EnhancedByCGLIB
something
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