Fix URL normalization when replacing /./ with /

Previously, a regular expression of /./ was used to replace /./ with
/.  The '.'' in the expression matches any single character so the
replacement was more broadly applicable than it should have been. For
example, /a/ would be replaced with /.

This commit uses Pattern.LITERAL to compile the regular expression
from the CURRENT_DIR (/./) contant. This allows the constant to be
used to check for occurances of /./ in the string before attempting
replacement, while also ensuring that the '.' is treated literally.

Closes gh-17341

spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/Handler.java

@@ -51,7 +51,7 @@ public class Handler extends URLStreamHandler {
 
 	private static final String CURRENT_DIR = "/./";
 
-	private static final Pattern CURRENT_DIR_PATTERN = Pattern.compile(CURRENT_DIR);
+	private static final Pattern CURRENT_DIR_PATTERN = Pattern.compile(CURRENT_DIR, Pattern.LITERAL);
 
 	private static final String PARENT_DIR = "/../";
 

spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/HandlerTests.java

@@ -130,7 +130,7 @@ public class HandlerTests {
 	@Test
 	public void urlWithSpecReferencingParentDirectory() throws MalformedURLException {
 		assertStandardAndCustomHandlerUrlsAreEqual("file:/test.jar!/BOOT-INF/classes!/xsd/folderA/a.xsd",
-				"../folderB/b.xsd");
+				"../folderB/c/d/e.xsd");
 	}
 
 	@Test
@@ -142,7 +142,7 @@ public class HandlerTests {
 	@Test
 	public void urlWithSpecReferencingCurrentDirectory() throws MalformedURLException {
 		assertStandardAndCustomHandlerUrlsAreEqual("file:/test.jar!/BOOT-INF/classes!/xsd/folderA/a.xsd",
-				"./folderB/./b.xsd");
+				"./folderB/c/d/e.xsd");
 	}
 
 	@Test