Spring 当beanPostProcessor 依赖target 时BeanPostProcessor 不能创建代理？

Question

我在这个问题上卡了一段时间无法解决sleep:C

当我使用 beanPostProcessor 为 beanA 创建代理时（beanPostProcessor 不依赖于 beanA），代理工作 well.But 如果 beanPostProcessor 依赖于 beanA，则它不工作 work.And 我发现 beanA 没有被代理Spring beanPostProcessor 依赖时的 ApplicationContext

目标人脸：

public interface TargetIface {
    void work();
}

目标A：

public class TargetA implements TargetIface {
    public void work() {
        System.out.println("targetA is working...");
    }
}

目标B：

public class TargetB implements TargetIface {
    public void work() {
        System.out.println("targetB is working...");
    }
}

简单顾问：

public class SimpleAdvisor extends DefaultPointcutAdvisor {

private TargetIface targetIface;

private final Advice advice = new MethodInterceptor() {
    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
        System.out.println("advice intercept....");
        if (invocation.getThis().equals(targetIface)) {
            System.out.println("my advice");
        }
        //no adivce
        return invocation.proceed();
    }
};

public SimpleAdvisor() {
    setAdvice(advice);
}

public void setTargetIface(TargetIface targetIface) {
    this.targetIface = targetIface;
}
}

beanPostProcessor:

public class ProxyProcessor implements BeanPostProcessor {


private List<Advisor> advisors;

@Override
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
    return bean;
}

@Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
    if (bean instanceof TargetIface) {
        ProxyFactory proxyFactory = new ProxyFactory();
        proxyFactory.setTarget(bean);
        proxyFactory.addAdvisors(advisors);

        return proxyFactory.getProxy();
    }
    return bean;
}

public void setAdvisors(List<Advisor> advisors) {
    this.advisors = advisors;
}
}

主类：

ApplicationContext context = new ClassPathXmlApplicationContext("classpath:spring/Application-context.xml");
    TargetA targetA = context.getBean(TargetA.class);
    targetA.work();

首先case:proxyBeanProcessor不依赖targetA

<bean id="proxyBeanProcessor" class="net.fendar.test.spring.processor.ProxyProcessor">
    <property name="advisors">
        <list>
            <bean class="net.fendar.test.spring.advisor.SimpleAdvisor">
                <!--<property name="targetIface" ref="targetA"/>-->
            </bean>
        </list>
    </property>
</bean>

<bean id="targetA" class="net.fendar.test.spring.bean.TargetA"/>
<bean id="targetB" class="net.fendar.test.spring.bean.TargetB"/>

输出：

advice intercept....
targetA is working...

applicationContext 中的 beanenter image description here

秒 case:proxyBeanProcessor 取决于目标，

<bean id="proxyBeanProcessor" class="net.fendar.test.spring.processor.ProxyProcessor">
    <property name="advisors">
        <list>
            <bean class="net.fendar.test.spring.advisor.SimpleAdvisor">
                <property name="targetIface" ref="targetA"/>
            </bean>
        </list>
    </property>
</bean>

<bean id="targetA" class="net.fendar.test.spring.bean.TargetA"/>
<bean id="targetB" class="net.fendar.test.spring.bean.TargetB"/>

<bean id="proxyBeanProcessor" class="net.fendar.test.spring.processor.ProxyProcessor">
    <property name="Target" ref="Target"/>
</bean>

输出：

targetA is working...

应用程序中的 bean：

enter image description here

Answer 1

如果您的 BeanPostProcessor bean 取决于您要代理的 bean

<bean id="proxyBeanProcessor" class="net.fendar.test.spring.processor.ProxyProcessor">
    <property name="Target" ref="Target"/>
</bean>

那么必须在您的 ProxyProcessor bean 准备好之前创建该 bean。而且，如果它还没有准备好，那么它就无法 post 处理任何其他 bean，包括您的目标 bean。

当 Spring 初始化您的 bean 时，它会通过所有已注册的 BeanPostProcessor bean 实例传递它们。这意味着 BeanPostProcesser beans 已经被初始化。您的案例演示了一个场景，其中一个 bean 在 BeanPostProcessor 之前被初始化，因此无法处理它。

Spring 当beanPostProcessor 依赖target 时BeanPostProcessor 不能创建代理？

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