@AfterThrowing 没有按预期工作 [英] @AfterThrowing not work as expected
问题描述
我想用AOP拦截服务层抛出的所有运行时异常，并作为域异常重新抛出.
I want to use AOP to intercept all runtime exceptions thrown in service layer and rethrow as domain exceptions.
@Aspect
@Component
public class ExceptionWrapperInterceptor {
@Pointcut("within(*.service.*)")
public void onlyServiceClasses() {}
@AfterThrowing(pointcut = "onlyServiceClasses()", throwing = "ex")
public void intercept(DataAccessException ex) throws Exception {
//throw DatabaseException
}
@AfterThrowing(pointcut = "onlyServiceClasses()", throwing = "ex")
public void intercept(RuntimeException ex) throws Exception {
//throw ServiceException
}
}
这里的问题是，对于 DataAccessException 的子类，运行时执行了错误的方法.有一个优雅的解决方案吗?
The problem here is that, with a subclass of DataAccessException, the runtime execute the wrong method. There is an elegant solution to this?
Spring 版本:4.2.4.RELEASE
Spring Version: 4.2.4.RELEASE
附言具有大量 instanceof 的单个通用方法(从其他问题中读取)对我来说并不优雅;-)
P.S. A single generic method (read from other questions) with a lot of instanceof is not elegant for me ;-)
谢谢弗朗切斯科
推荐答案
我相信，你的期望是错误的(只有一个拦截方法会与方法重载类似).
I believe, that your expectation is wrong (that only one intercept method will match similarly as for method overloading).
但是当 RuntimeException 是 DataAccessException 的父级时，两个方法都被执行了...
But while RuntimeException is parent of DataAccessException both methods are executed...
spring.xml
<?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"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.2.xsd">
<context:component-scan base-package="test" />
<aop:aspectj-autoproxy />
</beans>
AopTest
package test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class AopTest {
public static void main(String[] args) {
ApplicationContext ac = new ClassPathXmlApplicationContext("classpath:spring.xml");
MyService ms = ac.getBean(MyService.class);
try {
ms.throw1();
} catch (Exception e) {
// e.printStackTrace();
}
try {
ms.throw2();
} catch (Exception e) {
// e.printStackTrace();
}
}
}
我的方面
package test;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.dao.DataAccessException;
import org.springframework.stereotype.Component;
@Aspect
@Component
public class MyAspect {
@AfterThrowing(pointcut = "execution(public * *(..))", throwing = "ex")
public void intercept(DataAccessException ex) throws Exception {
//throw DatabaseException
System.out.println("DAE");
}
@AfterThrowing(pointcut = "execution(public * *(..))", throwing = "ex")
public void intercept(RuntimeException ex) throws Exception {
//throw ServiceException
System.out.println("RE - " + ex.getClass());
}
}
我的服务
package test;
import org.springframework.dao.DataAccessException;
import org.springframework.stereotype.Service;
@Service
public class MyService {
public void throw1() throws DataAccessException {
throw new MyDataAccessException("test");
}
public void throw2() {
throw new NullPointerException();
}
static class MyDataAccessException extends DataAccessException {
public MyDataAccessException(String msg) {
super(msg);
}
}
}
在日志中有:
DAE
RE - class test.MyService$MyDataAccessException
RE - class java.lang.NullPointerException
Maven 依赖项:
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aspects</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
当在同一个方面定义的两条通知都需要在同一个连接点运行时，排序是未定义的(因为对于 javac 编译的类，无法通过反射检索声明顺序).考虑将这些通知方法合并为每个方面类中每个连接点的一个通知方法，或者将这些通知部分重构为单独的方面类 - 可以在方面级别进行排序.
When two pieces of advice defined in the same aspect both need to run at the same join point, the ordering is undefined (since there is no way to retrieve the declaration order via reflection for javac-compiled classes). Consider collapsing such advice methods into one advice method per join point in each aspect class, or refactor the pieces of advice into separate aspect classes - which can be ordered at the aspect level.
当我尝试对 MyAspect 进行以下修改时:
When I tried following modification of MyAspect:
package test;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.dao.DataAccessException;
import org.springframework.stereotype.Component;
@Aspect
@Component
public class MyAspect {
@AfterThrowing(pointcut = "execution(public * *(..))", throwing = "ex")
public void intercept(DataAccessException ex) throws Exception {
//throw DatabaseException
System.out.println("DAE");
throw new IllegalArgumentException("DAE"); // added
}
@AfterThrowing(pointcut = "execution(public * *(..))", throwing = "ex")
public void intercept(RuntimeException ex) throws Exception {
//throw ServiceException
System.out.println("RE - " + ex.getClass());
throw new IllegalArgumentException("RE"); // added
}
}
日志更改为:
DAE
RE - class java.lang.IllegalArgumentException
RE - class java.lang.NullPointerException
当修改为 Exception 时，我得到了:
and when modified to Exception I got:
package test;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.dao.DataAccessException;
import org.springframework.stereotype.Component;
@Aspect
@Component
public class MyAspect {
@AfterThrowing(pointcut = "execution(public * *(..))", throwing = "ex")
public void intercept(DataAccessException ex) throws Exception {
//throw DatabaseException
System.out.println("DAE");
throw new Exception("DAE2"); // changed
}
@AfterThrowing(pointcut = "execution(public * *(..))", throwing = "ex")
public void intercept(RuntimeException ex) throws Exception {
//throw ServiceException
System.out.println("RE - " + ex.getClass());
throw new Exception("RE2"); // changed
}
}
日志是
DAE
RE - class java.lang.NullPointerException
我相信，解决您的问题"的方法是有两个方面而不是一个方面并定义排序:
I believe, that solution to your "problem" is to have two Aspects instead of one and define the ordering:
package test;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.core.Ordered;
import org.springframework.dao.DataAccessException;
import org.springframework.stereotype.Component;
@Aspect
@Component
public class DaeAspect implements Ordered {
public int getOrder() {
return 200;
}
@AfterThrowing(pointcut = "execution(public * *(..))", throwing = "ex")
public void intercept(DataAccessException ex) throws Exception {
//throw DatabaseException
System.out.println("DAE");
throw new IllegalAccessException("DAE2"); // based on my testing, this stops second aspect to apply
}
}
和
package test;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.core.Ordered;
import org.springframework.dao.DataAccessException;
import org.springframework.stereotype.Component;
@Aspect
@Component
public class ReAspect implements Ordered {
public int getOrder() {
return 100;
}
@AfterThrowing(pointcut = "execution(public * *(..))", throwing = "ex")
public void intercept(RuntimeException ex) throws Exception {
//throw ServiceException
System.out.println("RE - " + ex.getClass());
throw new IllegalAccessException("RE2");
}
}
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