java - spring 3.0 aop 切入点格式不正确 : expecting 'name pattern' error

Question

以下是我的切入点和advise声明

//PointCut on A method which takes two parameters and is in a DAO
@Pointcut("execution(backend.repository.QuestionsRepository.AnswerQuestion (..))")
public void answerQuestionPointCut() {}


@Around(
   value="web.activity.advisors.UserActivityAdvisor.answerQuestionPointCut()",
   argNames="question,answer"
)

 // Do something

}

出现以下错误

Initialization of bean failed; nested exception is java.lang.IllegalArgumentException: Pointcut is not well-formed: expecting 'name pattern' at character position 65
execution(backend.repository.QuestionsRepository.AnswerQuestion (..))
                                                                 ^

我坚持这个，任何指针

Answer 1

您缺少返回类型:

@Pointcut("execution(* backend.repository.QuestionsRepository.AnswerQuestion (..))")

并且您必须绑定(bind)参数名称，如下所示:

@Pointcut("execution(* backend.repository.QuestionsRepository.AnswerQuestion (..)) 
&& args(question, answer)") // wrapped for readability only

示例解决方案

服务接口(interface):

package foo.bar.service;
public interface Service{
    void whack(String thing, Integer thang);
}

实现类:

package foo.bar.service;
public class DefaultService implements Service{
    @Override
    public void whack(final String thing, final Integer thang){
        System.out.println(
            "Inside thing: " + thing + ", inside thang: " + thang
        );
    }
}

Spring AOP 方面:

@Aspect
public class ServiceAspect{

    @Pointcut("execution(* foo.bar.service.*.*(..))")
    public void serviceMethodExecution(){
    }

    @Around(value = "serviceMethodExecution() && args(param1, param2)")
    public void aroundServiceMethodExecution(final ProceedingJoinPoint pjp,
        final String param1,
        final Integer param2) throws Throwable{

        System.out.println("Before thing: " + param1 + ", before thang: "
            + param2);
        pjp.proceed();
        System.out.println("After thing: " + param1 + ", after thang: "
            + param2);
    }

}

Spring 上下文 XML:

<aop:aspectj-autoproxy proxy-target-class="false"  />
<bean class="foo.bar.service.DefaultService" />
<bean class="foo.bar.aspects.ServiceAspect" />

测试主类:

下面介绍一个测试整个过程的主要方法。它启动了一个 Spring ApplicationContext without XML configuration，上面的 XML 定义了服务 bean 和方面(事实证明，没有 XML 的解决方案只有效，因为我打开了 AspectJ 编织，我不知道我必须包含哪些 bean 才能启用 aspectj-autoproxy，所以我现在使用 ClassPathXmlApplicationContext 和这个最小的 XML):

public static void main(final String[] args){
    final ApplicationContext applicationContext =
        new ClassPathXmlApplicationContext("classpath:/aspectContext.xml");
    final Service service = applicationContext.getBean(Service.class);
    service.whack("abc", 123);
}

输出:

Before thing: abc, before thang: 123
Inside thing: abc, inside thang: 123
After thing: abc, after thang: 123

这应该可以帮助您入门。基本上:如果你使用 JDK 代理(spring 默认)，你需要检查你拦截的方法是否由服务接口(interface)支持。在这里阅读关于 Spring AOP proxy mechanisms 的信息.

注意:

如您所见，我将方法参数绑定(bind)到方面，而不是切入点，因此使切入点可重用于具有不同参数签名的方法。但也可以将它们绑定(bind)在切入点中，如下所示:

@Pointcut(value = "execution(* foo.bar.service.*.*(..)) && args(a,b)",
          argNames = "a,b")
public void serviceMethodExecution(final String a, final Integer b){
}

@Around(value = "serviceMethodExecution(param1, param2)",
        argNames = "param1,param2")
public void aroundServiceMethodExecution(final String param1,
    final Integer param2,
    final ProceedingJoinPoint pjp) throws Throwable{

    System.out.println("Before thing: " + param1 + ", before thang: "
        + param2);
    pjp.proceed();
    System.out.println("After thing: " + param1 + ", after thang: "
        + param2);
}