@AfterThrowing不能按預期工作

我想使用AOP來攔截在服務層中拋出的所有運行時異常，並將其重新拋出爲域例外。@AfterThrowing不能按預期工作

@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 
    } 

}

這裏的問題是，在DataAccessException的子類中，運行時執行錯誤的方法。有一個優雅的解決方案呢？

Spring版本：4.2.4.RELEASE

P.S.一個通用的方法（從其它問題讀取）有很多的instanceof是不優雅，我;-)

感謝弗朗西斯

來源

2016-01-05 Francesco

通過「方法不對」你的意思是，這兩種方法都執行的，對不對？ – Betlista

不。只有'攔截（RuntimeException）'方法。 – Francesco

你能檢查我的答案，並分享你的情況有什麼不同嗎？你沒有分享Spring版本，'onlyServiceClasses'和其他細節的定義... – Betlista

我相信，你的預期是錯誤的（只有一個監聽方法將匹配類似於方法重載）。

不過，雖然RuntimeException是執行這兩種方法的DataAccessException父...

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(); 
     } 
    } 
}

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"); 
    } 

    @AfterThrowing(pointcut = "execution(public * *(..))", throwing = "ex") 
    public void intercept(RuntimeException ex) throws Exception { 
     //throw ServiceException 
     System.out.println("RE - " + ex.getClass()); 
    } 

}

爲MyService

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); 
     } 

    } 
}

和在日誌有：

DAE 
RE - class test.MyService$MyDataAccessException 
RE - class java.lang.NullPointerException

Maven依賴：

<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>

From Spring documentation：

當在同一方面都需要在同一連接點運行定義的兩點建議，順序是不確定的（因爲沒有方法來檢索通過反射的聲明順序爲javac-編譯類）。考慮將這些通知方法分解爲每個方面類中每個連接點的一個通知方法，或者將通知重構爲單獨的方面類 - 可以在方面級別進行排序。

當我嘗試以下的MyAspect修改：

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 
    } 

}

日誌改爲：

DAE 
RE - class java.lang.IllegalArgumentException 
RE - class java.lang.NullPointerException

，並在修改爲Exception我：

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 
    } 

}

日誌是

DAE 
RE - class java.lang.NullPointerException

我相信，解決您的「問題」是要有的，而不是一個兩個方面定義排序：

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"); 
    } 

}

來源

2016-01-05 15:15:52 Betlista

我認爲這裏的流程與我的不同。您只需登錄並執行攔截器即可。我在第一種方法中拋出另一個與第二種方法不匹配的異常。 – Francesco

正如我寫的，你沒有分享重要的細節。我試圖拋出'IllegalArgumentException'，但它非常相似，我會在回答中提到這一點... – Betlista

有關使用@Around如何建議？你可以簡單地使用類型安全try-catch其中，無需使用任何instanceof或反射。

下面是使用AspectJ代替Spring AOP的，因爲我不是一個Spring用戶，我整理了一些示例代碼。無論如何，切入點應該是一樣的。

Helper類：

package de.scrum_master.service; 

public class DatabaseException extends RuntimeException { 
    public DatabaseException(Throwable arg0) { 
     super(arg0); 
    } 
}

package de.scrum_master.service; 

public class ServiceException extends RuntimeException { 
    public ServiceException(Throwable arg0) { 
     super(arg0); 
    } 
}

驅動程序（普通的Java，沒有必要使用Spring）：

package de.scrum_master.service; 

import java.util.Random; 
import org.springframework.jdbc.datasource.init.ScriptParseException; 

public class Application { 
    private static final Random RANDOM = new Random(); 

    public static void main(String[] args) { 
     Application application = new Application(); 
     for (int i = 0; i < 10; i++) { 
      try { 
       application.doSomething(); 
      } 
      catch (Exception e) { 
       System.out.println(e); 
      } 
     } 
    } 

    public void doSomething() { 
     switch (RANDOM.nextInt(3)) { 
      case 1: throw new ScriptParseException("uh-oh", null); 
      case 2: throw new IllegalArgumentException("WTF"); 
      default: System.out.println("doing something"); 
     } 
    } 
}

看點：

package de.scrum_master.aspect; 

import org.aspectj.lang.ProceedingJoinPoint; 
import org.aspectj.lang.annotation.Around; 
import org.aspectj.lang.annotation.Aspect; 
import org.aspectj.lang.annotation.Pointcut; 
import org.springframework.dao.DataAccessException; 
import org.springframework.stereotype.Component; 
import de.scrum_master.service.DatabaseException; 
import de.scrum_master.service.ServiceException; 

@Aspect 
@Component 
public class ExceptionWrapperInterceptor { 
    @Pointcut("within(*..service..*) && execution(* *(..))") 
    public void onlyServiceClasses() {} 

    @Around("onlyServiceClasses()") 
    public Object intercept(ProceedingJoinPoint thisJoinPoint) { 
     try { 
      return thisJoinPoint.proceed(); 
     } 
     catch (DataAccessException dae) { 
      throw new DatabaseException(dae); 
     } 
     catch (RuntimeException re) { 
      throw new ServiceException(re); 
     } 
    } 
}

控制檯日誌：

doing something 
de.scrum_master.service.DatabaseException: org.springframework.jdbc.datasource.init.ScriptParseException: Failed to parse SQL script from resource [<unknown>]: uh-oh 
doing something 
de.scrum_master.service.DatabaseException: org.springframework.jdbc.datasource.init.ScriptParseException: Failed to parse SQL script from resource [<unknown>]: uh-oh 
doing something 
de.scrum_master.service.ServiceException: java.lang.IllegalArgumentException: WTF 
de.scrum_master.service.ServiceException: java.lang.IllegalArgumentException: WTF 
de.scrum_master.service.ServiceException: java.lang.IllegalArgumentException: WTF 
de.scrum_master.service.ServiceException: java.lang.IllegalArgumentException: WTF 
doing something

來源

2016-01-10 11:13:37 kriegaex

@AfterThrowing不能按預期工作

回答

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