Improve efficiency of UrlPathHelper#getSanitizedPath

See gh-27623

spring-web/src/main/java/org/springframework/web/util/UrlPathHelper.java

@@ -405,17 +405,18 @@ public class UrlPathHelper {
 	 * </ul>
 	 */
 	private static String getSanitizedPath(final String path) {
-		int index = path.indexOf("//");
+		if (path.length() == 0) {
-		if (index >= 0) {
-			StringBuilder sanitized = new StringBuilder(path);
-			while (index != -1) {
-				sanitized.deleteCharAt(index);
-				index = sanitized.indexOf("//", index);
-			}
-			return sanitized.toString();
-		}
 			return path;
 		}
+		char[] arr = path.toCharArray();
+		int slowIndex = 0;
+		for (int fastIndex = 1; fastIndex < arr.length; fastIndex++) {
+			if (arr[fastIndex] != '/' || arr[slowIndex] != '/') {
+				arr[++slowIndex] = arr[fastIndex];
+			}
+		}
+		return new String(arr, 0, slowIndex + 1);
+	}
 
 	/**
 	 * Return the request URI for the given request, detecting an include request

spring-web/src/test/java/org/springframework/web/util/UrlPathHelperTests.java

@@ -246,6 +246,12 @@ class UrlPathHelperTests {
 		request.setRequestURI("/SPR-12372/foo/bar//");
 
 		assertThat(helper.getLookupPathForRequest(request)).isEqualTo("/foo/bar//");
+
+		// "enhance" case
+		request.setServletPath("/foo/bar//");
+		request.setRequestURI("/SPR-12372////////////////////////foo//////////////////bar////////////////////");
+
+		assertThat(helper.getLookupPathForRequest(request)).isEqualTo("/foo/bar//");
 	}
 
 	@Test