如何将AOP与AspectJ一起使用进行日志记录？

Question

我想将“跟踪”消息添加到我的所有公共方法中，如下所示：

public void foo（s：String，n：int）{//日志是log4j记录器或任何其他库

  log.trace（String.format（“使用s输入foo：％s，n：％d”，s，n））

  ...

  log.trace（“退出foo”） 

}

现在，我想log.trace使用AOP（和字节码检测）将所有这些自动添加到我的方法中。我在想AspectJ。是否有意义？您知道开源吗？

Answer 1

我创建了一个简单的方面来捕获公共方法的执行。该AspectJ代码的核心是切入点定义：pointcut publicMethodExecuted(): execution(public * *(..));在这里，我们将捕获具有任何返回类型，任何包和任何类，具有任意数量的参数的所有公共方法。建议的执行情况可以在下面的代码段中看到：after(): publicMethodExecuted() {&nbsp; &nbsp; System.out.printf("Enters on method: %s. \n", thisJoinPoint.getSignature());&nbsp; &nbsp; Object[] arguments = thisJoinPoint.getArgs();&nbsp; &nbsp; for (int i =0; i < arguments.length; i++){&nbsp; &nbsp; &nbsp; &nbsp; Object argument = arguments[i];&nbsp; &nbsp; &nbsp; &nbsp; if (argument != null){&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; System.out.printf("With argument of type %s and value %s. \n", argument.getClass().toString(), argument);&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; }&nbsp; &nbsp; System.out.printf("Exits method: %s. \n", thisJoinPoint.getSignature());}该建议使用thisJoinPoint获取方法签名和参数。就是这样。这是方面代码：public aspect LogAspect {pointcut publicMethodExecuted(): execution(public * *(..));after(): publicMethodExecuted() {&nbsp; &nbsp; System.out.printf("Enters on method: %s. \n", thisJoinPoint.getSignature());&nbsp; &nbsp; Object[] arguments = thisJoinPoint.getArgs();&nbsp; &nbsp; for (int i =0; i < arguments.length; i++){&nbsp; &nbsp; &nbsp; &nbsp; Object argument = arguments[i];&nbsp; &nbsp; &nbsp; &nbsp; if (argument != null){&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; System.out.printf("With argument of type %s and value %s. \n", argument.getClass().toString(), argument);&nbsp; &nbsp; &nbsp; &nbsp; }&nbsp; &nbsp; }&nbsp; &nbsp; System.out.printf("Exits method: %s. \n", thisJoinPoint.getSignature());}对于更复杂的示例，我会推荐《AspectJ：在行动》一书。