你不能通过args()AspectJ 中的任意位置绑定参数,因为这可能会导致歧义。试想一下,你有两个或多个相同类型的参数(在这种情况下,使用相同的注释类型进行了注释)。应将其中哪一个绑定到命名args()参数?所以当
execution(public * (.., @Deprecated (), ..)) 可以作为独立的表达式(请注意星号的括号),不能与组合使用args()。因此,如果你不仅要拦截方法本身的执行,而且要查找具有给定批注的第一个或所有参数,则需要执行我在另一篇文章中所展示的。我有点重复自己,但是为了不再次删除答案是这样的:
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
@Retention(RetentionPolicy.RUNTIME)
public @interface Constraint {}
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class Application {
public void method1(@Constraint int i) {}
public void method2(String id, @Constraint float f) {}
public void method3(int i, @Constraint List<String> strings, @Constraint String s) {}
public void method4(int i, @Constraint Set<Integer> numbers, float f, boolean b) {}
public void method5(boolean b, String s, @Constraint String s2, float f, int i) {}
public void notintercepted(boolean b, String s, String s2, float f, int i) {}
public static void main(String[] args) {
List<String> strings = new ArrayList<String>();
strings.add("foo");
strings.add("bar");
Set<Integer> numbers = new HashSet<Integer>();
numbers.add(11);
numbers.add(22);
numbers.add(33);
Application app = new Application();
app.method1(1);
app.method2("foo", 1f);
app.method3(1, strings, "foo");
app.method4(1, numbers, 1f, true);
app.method5(false, "foo", "bar", 1f, 1);
app.notintercepted(false, "foo", "bar", 1f, 1);
}
}
import java.lang.annotation.Annotation;
import org.aspectj.lang.softException;
import org.aspectj.lang.reflect.MethodSignature;
public aspect ArgCatcherAspect {
before() : execution(public * *(.., @Constraint (*), ..)) {
System.out.println(thisJoinPointStaticPart);
MethodSignature signature = (MethodSignature) thisJoinPoint.getSignature();
String methodName = signature.getmethod().getName();
Class<?>[] parameterTypes = signature.getmethod().getParameterTypes();
Annotation[][] annotations;
try {
annotations = thisJoinPoint.getTarget().getClass().
getmethod(methodName, parameterTypes).getParameterAnnotations();
} catch (Exception e) {
throw new SoftException(e);
}
int i = 0;
for (Object arg : thisJoinPoint.getArgs()) {
for (Annotation annotation : annotations[i]) {
if (annotation.annotationType() == Constraint.class)
System.out.println(" " + annotation + " -> " + arg);
}
i++;
}
}
}