Escape URL characters in JAR URLs

Update the spring-boot-loader JarURLConnection class to decode entry
names in the same way as the stock JDK class. This allows encoded
entry names in the form `%c3%ab` to be loaded.

Fixes gh-556

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

@@ -16,9 +16,11 @@
 
 package org.springframework.boot.loader.jar;
 
+import java.io.ByteArrayOutputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.UnsupportedEncodingException;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.jar.Manifest;
@@ -64,7 +66,7 @@ class JarURLConnection extends java.net.JarURLConnection {
 		 */
 		if (separator + SEPARATOR.length() != spec.length()) {
 			this.jarFileUrl = new URL("jar:" + spec);
-			this.jarEntryName = spec.substring(separator + 2);
+			this.jarEntryName = decode(spec.substring(separator + 2));
 		}
 		else {
 			// The root of the archive (!/)
@@ -162,4 +164,39 @@ class JarURLConnection extends java.net.JarURLConnection {
 		return builder.toString();
 	}
 
+	private static String decode(String source) {
+		int length = source.length();
+		if ((length == 0) || (source.indexOf('%') < 0)) {
+			return source;
+		}
+		try {
+			ByteArrayOutputStream bos = new ByteArrayOutputStream(length);
+			for (int i = 0; i < length; i++) {
+				int ch = source.charAt(i);
+				if (ch == '%') {
+					if ((i + 2) >= length) {
+						throw new IllegalArgumentException("Invalid encoded sequence \""
+								+ source.substring(i) + "\"");
+					}
+					ch = decodeEscapeSequence(source, i);
+					i += 2;
+				}
+				bos.write(ch);
+			}
+			return new String(bos.toByteArray(), "UTF-8");
+		}
+		catch (UnsupportedEncodingException ex) {
+			throw new IllegalStateException(ex);
+		}
+	}
+
+	private static char decodeEscapeSequence(String source, int i) {
+		int hi = Character.digit(source.charAt(i + 1), 16);
+		int lo = Character.digit(source.charAt(i + 2), 16);
+		if (hi == -1 || lo == -1) {
+			throw new IllegalArgumentException("Invalid encoded sequence \""
+					+ source.substring(i) + "\"");
+		}
+		return ((char) ((hi << 4) + lo));
+	}
 }

spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/TestJarCreator.java

@@ -43,6 +43,8 @@ public abstract class TestJarCreator {
 			writeEntry(jarOutputStream, "2.dat", 2);
 			writeDirEntry(jarOutputStream, "d/");
 			writeEntry(jarOutputStream, "d/9.dat", 9);
+			writeDirEntry(jarOutputStream, "special/");
+			writeEntry(jarOutputStream, "special/\u00EB.dat", '\u00EB');
 
 			JarEntry nestedEntry = new JarEntry("nested.jar");
 			byte[] nestedJarData = getNestedJarData();
@@ -68,6 +70,7 @@ public abstract class TestJarCreator {
 		writeManifest(jarOutputStream, "j2");
 		writeEntry(jarOutputStream, "3.dat", 3);
 		writeEntry(jarOutputStream, "4.dat", 4);
+		writeEntry(jarOutputStream, "\u00E4.dat", '\u00E4');
 		jarOutputStream.close();
 		return byteArrayOutputStream.toByteArray();
 	}

spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/archive/ExplodedArchiveTests.java

@@ -100,7 +100,7 @@ public class ExplodedArchiveTests {
 	@Test
 	public void getEntries() throws Exception {
 		Map<String, Archive.Entry> entries = getEntriesMap(this.archive);
-		assertThat(entries.size(), equalTo(7));
+		assertThat(entries.size(), equalTo(9));
 	}
 
 	@Test

spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/archive/JarFileArchiveTests.java

@@ -62,7 +62,7 @@ public class JarFileArchiveTests {
 	@Test
 	public void getEntries() throws Exception {
 		Map<String, Archive.Entry> entries = getEntriesMap(this.archive);
-		assertThat(entries.size(), equalTo(7));
+		assertThat(entries.size(), equalTo(9));
 	}
 
 	@Test

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

@@ -21,6 +21,7 @@ import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.URL;
+import java.net.URLClassLoader;
 import java.util.Enumeration;
 import java.util.jar.JarEntry;
 import java.util.jar.Manifest;
@@ -50,6 +51,7 @@ import static org.mockito.Mockito.verify;
  * Tests for {@link JarFile}.
  * 
  * @author Phillip Webb
+ * @author Martin Lau
  */
 public class JarFileTests {
 
@@ -70,6 +72,26 @@ public class JarFileTests {
 		this.jarFile = new JarFile(this.rootJarFile);
 	}
 
+	@Test
+	public void jdkJarFile() throws Exception {
+		// Sanity checks to see how the default jar file operates
+		java.util.jar.JarFile jarFile = new java.util.jar.JarFile(this.rootJarFile);
+		Enumeration<java.util.jar.JarEntry> entries = jarFile.entries();
+		assertThat(entries.nextElement().getName(), equalTo("META-INF/"));
+		assertThat(entries.nextElement().getName(), equalTo("META-INF/MANIFEST.MF"));
+		assertThat(entries.nextElement().getName(), equalTo("1.dat"));
+		assertThat(entries.nextElement().getName(), equalTo("2.dat"));
+		assertThat(entries.nextElement().getName(), equalTo("d/"));
+		assertThat(entries.nextElement().getName(), equalTo("d/9.dat"));
+		assertThat(entries.nextElement().getName(), equalTo("special/"));
+		assertThat(entries.nextElement().getName(), equalTo("special/\u00EB.dat"));
+		assertThat(entries.nextElement().getName(), equalTo("nested.jar"));
+		assertThat(entries.hasMoreElements(), equalTo(false));
+		URL jarUrl = new URL("jar:" + this.rootJarFile.toURI() + "!/");
+		URLClassLoader urlClassLoader = new URLClassLoader(new URL[] { jarUrl });
+		assertThat(urlClassLoader.getResource("special/\u00EB.dat"), notNullValue());
+	}
+
 	@Test
 	public void createFromFile() throws Exception {
 		JarFile jarFile = new JarFile(this.rootJarFile);
@@ -99,10 +121,19 @@ public class JarFileTests {
 		assertThat(entries.nextElement().getName(), equalTo("2.dat"));
 		assertThat(entries.nextElement().getName(), equalTo("d/"));
 		assertThat(entries.nextElement().getName(), equalTo("d/9.dat"));
+		assertThat(entries.nextElement().getName(), equalTo("special/"));
+		assertThat(entries.nextElement().getName(), equalTo("special/\u00EB.dat"));
 		assertThat(entries.nextElement().getName(), equalTo("nested.jar"));
 		assertThat(entries.hasMoreElements(), equalTo(false));
 	}
 
+	@Test
+	public void getSpecialResourceViaClassLoader() throws Exception {
+		URLClassLoader urlClassLoader = new URLClassLoader(
+				new URL[] { this.jarFile.getUrl() });
+		assertThat(urlClassLoader.getResource("special/\u00EB.dat"), notNullValue());
+	}
+
 	@Test
 	public void getJarEntry() throws Exception {
 		java.util.jar.JarEntry entry = this.jarFile.getJarEntry("1.dat");
@@ -204,6 +235,7 @@ public class JarFileTests {
 		assertThat(entries.nextElement().getName(), equalTo("META-INF/MANIFEST.MF"));
 		assertThat(entries.nextElement().getName(), equalTo("3.dat"));
 		assertThat(entries.nextElement().getName(), equalTo("4.dat"));
+		assertThat(entries.nextElement().getName(), equalTo("\u00E4.dat"));
 		assertThat(entries.hasMoreElements(), equalTo(false));
 
 		InputStream inputStream = nestedJarFile.getInputStream(nestedJarFile