带方面参数的注释

Question

我有一个可用于注释的方面：

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface DumpToFile {

}

连接点：

@Aspect
@Component
public class DumpToFileAspect {

  @Around("@annotation(DumpToFile)")
  public Object logExecutionTime(ProceedingJoinPoint joinPoint) throws Throwable {

    ...
    // I likte to read out a parameter from the annotation...
    Object proceed = joinPoint.proceed();

    ...

    return proceed;
  }
}

我可以在具有@DumpToFile的方法上成功使用方面；然而，我想将一个参数传递给注释，并在我的方面中检索它的值
例如@DumpToFile（fileName=“mydump”）。谁能告诉我怎么做吗？




Answer 1

匿名用户

您可以使用：

 @Around("@annotation(dumpFile)")
  public Object logExecutionTime(ProceedingJoinPoint joinPoint,DumpToFile dumpFile) 

< code>@annotation内部必须是< code>DumpToFile参数名。

详情看留档

Answer 2

将@Around改为：

@Aspect
@Component
public class DumpToFileAspect {

  @Around("@annotation(dumpToFileAspect)")
  public Object logExecutionTime(ProceedingJoinPoint joinPoint, DumpToFile dumpToFileAspect) throws Throwable {

    ...
    // I likte to read out a parameter from the annotation...
    String fileName = dumpToFileAspect.getFileName();
    Object proceed = joinPoint.proceed();

    ...

    return proceed;
  }
}

Answer 3

您应该能够将注释接口传递给拦截器方法。不过我自己还没有尝试过。

Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface DumpToFile {

      String fileName() default "default value";

}

在转储到文件检查中 -

@Aspect
@Component
public class DumpToFileAspect {

  @Around("@annotation(dtf)")
  public Object logExecutionTime(ProceedingJoinPoint joinPoint, DumpToFile dtf) throws Throwable {

    ...
    // I likte to read out a parameter from the annotation...

    System.out.println(dtf.fileName); // will print "fileName"

    Object proceed = joinPoint.proceed();

    ...

    return proceed;
  }
}