Question

我写了简单的Spring应用程序使用xml中的配置：

  <bean id="flyingDelegate" class="pl.marcindebski.spring.aspects.LowFlyingKnight"></bean>

  <aop:config>
    <aop:aspect ref="usageTracking">
        <aop:declare-parents
            types-matching="pl.marcindebski.spring.aspects.Knight+"
            implement-interface="pl.marcindebski.spring.aspects.FlyingKnight"
            delegate-ref="flyingDelegate"
            />
    </aop:aspect>
  </aop:config>

当我使用代码运行app时：

    Knight knight = context.getBean(Knight.class);

    if (knight instanceof FlyingKnight)
    {
        FlyingKnight flyingKnight =(FlyingKnight)knight;                                                
        flyingKnight.fly();
    }

context.close();

在我flyingKnight.fly();的行上：

Exception in thread "main" org.springframework.aop.AopInvocationException: AOP configuration seems to be invalid: tried calling method [public abstract void pl.marcindebski.spring.aspects.FlyingKnight.fly()] on target [pl.marcindebski.spring.aspects.BraveKnight@5e82df6a]; nested exception is java.lang.IllegalArgumentException: object is not an instance of declaring class

问题：

1）类LowFlyingKnight从fly()接口实现FlyingKnight方法。为什么Spring认为Knight FlyingKnight（knight instanceof FlyingKnight）是正确的，但是在调用fly()方法时失败了。

2）BraveKnight类是Knight接口的一个实现，所以为什么knight instanceof BraveKnight为false，但是knight.embarkOnQuest从BraveKnight执行实现

主要课程 - ＆gt; App.java

package pl.marcindebski.spring.aspects;

import org.springframework.context.support.FileSystemXmlApplicationContext;

public class App {

    public static void main(String[] args) throws Exception {
        FileSystemXmlApplicationContext context = new FileSystemXmlApplicationContext(
                new String[] {
                        "E:/dev/eclipse-workspaces/1-aspects/flying.xml",
                        "E:/dev/eclipse-workspaces/1-aspects/minstrel.xml" });

        Knight braveKnight = context.getBean(Knight.class);
        if (braveKnight instanceof BraveKnight) { // FALSE!
            braveKnight.embarkOnQuest();
        }

        braveKnight.embarkOnQuest(); // Working!

        if (braveKnight instanceof FlyingKnight) // true
        {
            FlyingKnight flyingKnight = (FlyingKnight) braveKnight;
            flyingKnight.fly();// why its not working ?
        }

        context.close();
    }

}

方面：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:aop="http://www.springframework.org/schema/aop"
  xsi:schemaLocation="http://www.springframework.org/schema/aop 
      http://www.springframework.org/schema/aop/spring-aop.xsd
        http://www.springframework.org/schema/beans 
      http://www.springframework.org/schema/beans/spring-beans.xsd">


  <bean id="flyingDelegate" class="pl.marcindebski.spring.aspects.LowFlyingKnight"></bean>

  <aop:config>
    <aop:aspect>
        <aop:declare-parents
            types-matching="pl.marcindebski.spring.aspects.Knight+"
            implement-interface="pl.marcindebski.spring.aspects.FlyingKnight"
            delegate-ref="flyingDelegate"
            />
    </aop:aspect>
  </aop:config>

</beans>

bean定义：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:aop="http://www.springframework.org/schema/aop"
  xsi:schemaLocation="http://www.springframework.org/schema/aop 
      http://www.springframework.org/schema/aop/spring-aop.xsd
        http://www.springframework.org/schema/beans 
      http://www.springframework.org/schema/beans/spring-beans.xsd">

  <bean id="knight" class="pl.marcindebski.spring.aspects.BraveKnight">
    <constructor-arg ref="quest" />
  </bean>

  <bean id="quest" class="pl.marcindebski.spring.aspects.SlayDragonQuest">
    <constructor-arg value="#{T(System).out}" />
  </bean>

  <bean id="minstrel" class="pl.marcindebski.spring.aspects.Minstrel">
    <constructor-arg value="#{T(System).out}" />
  </bean>

  <aop:config>
    <aop:aspect ref="minstrel">
      <aop:pointcut id="embark"
          expression="execution(* *.embarkOnQuest(..))"/>

      <aop:before pointcut-ref="embark" 
          method="singBeforeQuest"/>

      <aop:after pointcut-ref="embark" 
          method="singAfterQuest"/>
    </aop:aspect>
  </aop:config>

</beans>

Spring：object不是声明类的实例

0 个答案: