after-throwing
是一種通知類型,只有在方法通過拋出異常退出時才能確保方法執行後才能運行通知。 以下是after-throwing
通知的語法:
語法
<aop:config>
<aop:aspect id="log" ref="logging">
<aop:pointcut id="pointcut-id" expression="execution( expression )"/>
<aop:after-throwing pointcut-ref="pointcut-id" throwing="ex" method="methodName"/>
</aop:aspect>
</aop:config>
在上面配置中,
pointcut-id
- 切入點的id。ex
- 要被被拋出例外。methodName
- 在調用函數之前調用的函數的方法名稱。
要瞭解上述與之後拋出通知(After Throwing Advice)相關的概念,寫一個在實現之後拋出通知(After Throwing Advice)的示例。為了簡單,可直接複製之前上一篇文章中的例子,打開並使用Eclipse IDE,並按照以下步驟創建一個Spring應用程式:
- 更新在Spring AOP應用實例中創建過的
Student
專案。 - 更新bean配置並運行應用程式,如下所述。
整個專案的目錄結構如下所示 -
下麵是Logging.java
檔的內容。 這實際上是一個Aspect
模組的樣本,它定義了在各個點被調用的方法。
package com.zaixian;
public class Logging {
/**
* This is the method which I would like to execute
* if there is an exception raised.
*/
public void afterThrowingAdvice(IllegalArgumentException ex){
System.out.println("[afterThrowingAdvice] There has been an exception: " + ex.toString());
}
}
以下是Student.java檔的內容:
package com.zaixian;
public class Student {
private Integer age;
private String name;
public void setAge(Integer age) {
this.age = age;
}
public Integer getAge() {
System.out.println("Age : " + age );
System.out.println("Exception raised");
throw new IllegalArgumentException();
return age;
}
public void setName(String name) {
this.name = name;
}
public String getName() {
System.out.println("Name : " + name );
return name;
}
public void printThrowException(){
System.out.println("Exception raised");
throw new IllegalArgumentException();
}
}
以下是MainApp.java
檔的內容:
package com.zaixian;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class MainApp {
public static void main(String[] args) {
ApplicationContext context =
new ClassPathXmlApplicationContext("Beans.xml");
Student student = (Student) context.getBean("student");
student.printThrowException();
}
}
以下是配置檔Beans.xml檔的內容:
<?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/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd ">
<aop:config>
<aop:aspect id="log" ref="logging">
<aop:pointcut id="selectAll"
expression="execution(* com.zaixian.*.*(..))"/>
<aop:after-throwing pointcut-ref="selectAll" throwing="ex" method="afterThrowingAdvice"/>
</aop:aspect>
</aop:config>
<!-- Definition for student bean -->
<bean id="student" class="com.zaixian.Student">
<property name="name" value="maxsu" />
<property name="age" value="25" />
</bean>
<!-- Definition for logging aspect -->
<bean id="logging" class="com.zaixian.Logging"/>
</beans>
運行專案
完成創建源代碼和配置檔後,運行應用程式。右鍵單擊應用程式中的MainApp.java
,並使用運行方式作為Java應用程式命令。 如果您的應用程式一切正常,這將列印以下消息:
Exception raised
[afterThrowingAdvice] There has been an exception: java.lang.IllegalArgumentException
Exception in thread "main" java.lang.IllegalArgumentException
at com.zaixian.Student.printThrowException(Student.java:27)
at com.zaixian.Student$$FastClassBySpringCGLIB$$e9280b4b.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:717)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.aop.aspectj.AspectJAfterThrowingAdvice.invoke(AspectJAfterThrowingAdvice.java:58)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:653)
at com.zaixian.Student$$EnhancerBySpringCGLIB$$47620070.printThrowException(<generated>)
at com.zaixian.MainApp.main(MainApp.java:13)