Improve StringUtils.cleanPath

Issue: SPR-11793

spring-core/src/main/java/org/springframework/util/StringUtils.java

@@ -622,7 +622,12 @@ public abstract class StringUtils {
 		String prefix = "";
 		if (prefixIndex != -1) {
 			prefix = pathToUse.substring(0, prefixIndex + 1);
-			pathToUse = pathToUse.substring(prefixIndex + 1);
+			if (prefix.contains("/")) {
+				prefix = "";
+			}
+			else {
+				pathToUse = pathToUse.substring(prefixIndex + 1);
+			}
 		}
 		if (pathToUse.startsWith(FOLDER_SEPARATOR)) {
 			prefix = prefix + FOLDER_SEPARATOR;

spring-core/src/test/java/org/springframework/util/StringUtilsTests.java

@@ -299,6 +299,8 @@ public class StringUtilsTests extends TestCase {
 		assertEquals("../mypath/myfile", StringUtils.cleanPath("../mypath/../mypath/myfile"));
 		assertEquals("../mypath/myfile", StringUtils.cleanPath("mypath/../../mypath/myfile"));
 		assertEquals("/../mypath/myfile", StringUtils.cleanPath("/../mypath/myfile"));
+		assertEquals("/mypath/myfile", StringUtils.cleanPath("/a/:b/../../mypath/myfile"));
+		assertEquals("file:///c:/path/to/the%20file.txt", StringUtils.cleanPath("file:///c:/some/../path/to/the%20file.txt"));
 	}
 
 	public void testPathEquals() {