Improve performance of FormContentFilter

Improve the performance of `FormContentFilter` by checking directly if
`contentType` is empty. This saves the need for an exception to thrown
then immediately caught.

Closes gh-23216

Author: philwebb

spring-web/src/main/java/org/springframework/web/filter/FormContentFilter.java

@@ -109,16 +109,17 @@ public InputStream getBody() throws IOException {
 	}
 
 	private boolean shouldParse(HttpServletRequest request) {
-		if (!HTTP_METHODS.contains(request.getMethod())) {
-			return false;
-		}
-		try {
-			MediaType mediaType = MediaType.parseMediaType(request.getContentType());
-			return MediaType.APPLICATION_FORM_URLENCODED.includes(mediaType);
-		}
-		catch (IllegalArgumentException ex) {
-			return false;
+		String contentType = request.getContentType();
+		String method = request.getMethod();
+		if (StringUtils.hasLength(contentType) && HTTP_METHODS.contains(method)) {
+			try {
+				MediaType mediaType = MediaType.parseMediaType(contentType);
+				return MediaType.APPLICATION_FORM_URLENCODED.includes(mediaType);
+			}
+			catch (IllegalArgumentException ex) {
+			}
 		}
+		return false;
 	}