@ExceptionHandler support for non-@Controller handlers

Closes gh-22619

spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerExceptionResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -180,8 +180,16 @@ public abstract class AbstractHandlerExceptionResolver implements HandlerExcepti
 				}
 			}
 		}
-		// Else only apply if there are no explicit handler mappings.
-		return (this.mappedHandlers == null && this.mappedHandlerClasses == null);
+		return !hasHandlerMappings();
+	}
+
+	/**
+	 * Whether there are any handler mappings registered via
+	 * {@link #setMappedHandlers(Set)} or {@link #setMappedHandlerClasses(Class[])}.
+	 * @since 5.3
+	 */
+	protected boolean hasHandlerMappings() {
+		return (this.mappedHandlers != null || this.mappedHandlerClasses != null);
 	}
 
 	/**

spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerMethodExceptionResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -48,17 +48,31 @@ public abstract class AbstractHandlerMethodExceptionResolver extends AbstractHan
 			handler = handlerMethod.getBean();
 			return super.shouldApplyTo(request, handler);
 		}
+		else if (hasGlobalExceptionHandlers() && hasHandlerMappings()) {
+			return super.shouldApplyTo(request, handler);
+		}
 		else {
 			return false;
 		}
 	}
 
+	/**
+	 * Whether this resolver has global exception handlers, e.g. not declared in
+	 * the same class as the {@code HandlerMethod} that raised the exception and
+	 * therefore can apply to any handler.
+	 * @since 5.3
+	 */
+	protected boolean hasGlobalExceptionHandlers() {
+		return false;
+	}
+
 	@Override
 	@Nullable
 	protected final ModelAndView doResolveException(
 			HttpServletRequest request, HttpServletResponse response, @Nullable Object handler, Exception ex) {
 
-		return doResolveHandlerMethodException(request, response, (HandlerMethod) handler, ex);
+		HandlerMethod handlerMethod = (handler instanceof HandlerMethod ? (HandlerMethod) handler : null);
+		return doResolveHandlerMethodException(request, response, handlerMethod, ex);
 	}
 
 	/**

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ExceptionHandlerExceptionResolver.java

@@ -380,6 +380,10 @@ public class ExceptionHandlerExceptionResolver extends AbstractHandlerMethodExce
 		return handlers;
 	}
 
+	@Override
+	protected boolean hasGlobalExceptionHandlers() {
+		return !this.exceptionHandlerAdviceCache.isEmpty();
+	}
 
 	/**
 	 * Find an {@code @ExceptionHandler} method and invoke it to handle the raised exception.