Improve annotation aspect to support throwing original exception in fallback and blockHandler (#986)

- extract the original exception from InvocationTargetException

sentinel-extension/sentinel-annotation-aspectj/src/main/java/com/alibaba/csp/sentinel/annotation/aspectj/AbstractSentinelAspectSupport.java

@@ -21,10 +21,10 @@ import com.alibaba.csp.sentinel.log.RecordLog;
 import com.alibaba.csp.sentinel.slots.block.BlockException;
 import com.alibaba.csp.sentinel.util.MethodUtil;
 import com.alibaba.csp.sentinel.util.StringUtil;
-
 import org.aspectj.lang.ProceedingJoinPoint;
 import org.aspectj.lang.reflect.MethodSignature;
 
+import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.util.Arrays;
@@ -100,10 +100,16 @@ public abstract class AbstractSentinelAspectSupport {
                 args = Arrays.copyOf(originArgs, originArgs.length + 1);
                 args[args.length - 1] = ex;
             }
-            if (isStatic(fallbackMethod)) {
-                return fallbackMethod.invoke(null, args);
+
+            try {
+                if (isStatic(fallbackMethod)) {
+                    return fallbackMethod.invoke(null, args);
+                }
+                return fallbackMethod.invoke(pjp.getTarget(), args);
+            } catch (InvocationTargetException e) {
+                // throw the actual exception
+                throw e.getTargetException();
             }
-            return fallbackMethod.invoke(pjp.getTarget(), args);
         }
         // If fallback is absent, we'll try the defaultFallback if provided.
         return handleDefaultFallback(pjp, defaultFallback, fallbackClass, ex);
@@ -116,10 +122,15 @@ public abstract class AbstractSentinelAspectSupport {
         if (fallbackMethod != null) {
             // Construct args.
             Object[] args = fallbackMethod.getParameterTypes().length == 0 ? new Object[0] : new Object[] {ex};
-            if (isStatic(fallbackMethod)) {
-                return fallbackMethod.invoke(null, args);
+            try {
+                if (isStatic(fallbackMethod)) {
+                    return fallbackMethod.invoke(null, args);
+                }
+                return fallbackMethod.invoke(pjp.getTarget(), args);
+            } catch (InvocationTargetException e) {
+                // throw the actual exception
+                throw e.getTargetException();
             }
-            return fallbackMethod.invoke(pjp.getTarget(), args);
         }
 
         // If no any fallback is present, then directly throw the exception.
@@ -137,10 +148,15 @@ public abstract class AbstractSentinelAspectSupport {
             // Construct args.
             Object[] args = Arrays.copyOf(originArgs, originArgs.length + 1);
             args[args.length - 1] = ex;
-            if (isStatic(blockHandlerMethod)) {
-                return blockHandlerMethod.invoke(null, args);
+            try {
+                if (isStatic(blockHandlerMethod)) {
+                    return blockHandlerMethod.invoke(null, args);
+                }
+                return blockHandlerMethod.invoke(pjp.getTarget(), args);
+            } catch (InvocationTargetException e) {
+                // throw the actual exception
+                throw e.getTargetException();
             }
-            return blockHandlerMethod.invoke(pjp.getTarget(), args);
         }
 
         // If no block handler is present, then go to fallback.