I have some code below that is being used to scan for my batis mapper files. I'm scanning for a My Batis file, but I think my problem is more a Spring issue.
The code listed has been working fine, but when I add dependency to certain external library that is stored in my local maven repo, the PathMatchingResourcePatternResolver.getResources() method returns a resource of "file:/" for a specific jar. This is causing spring to search my entire C drive for mapper files.
I was able to determine what jar is causing this behavior but I'm not sure what the resolution is. Why is Spring setting the Resource to "file:/" ? I'm not sure what is wrong with this jar vs others that return a normal resource entry.
SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
PathMatchingResourcePatternResolver patternResolver = new PathMatchingResourcePatternResolver();
Resource configLocation = patternResolver.getResource("classpath:mybatis/mybatis.config.xml");
//this line leads to the issue
Resource[] mapperLocations1 = patternResolver.getResources("classpath*:**/*Mapper.xml");
//this is from the Spring PathMatchingResourcePatternResolver class
protected Resource[] findPathMatchingResources(String locationPattern) throws IOException {
String rootDirPath = determineRootDir(locationPattern);
String subPattern = locationPattern.substring(rootDirPath.length());
Resource[] rootDirResources = getResources(rootDirPath);
Set<Resource> result = new LinkedHashSet<Resource>(16);
for (Resource rootDirResource : rootDirResources) {
rootDirResource = resolveRootDirResource(rootDirResource);
URL rootDirUrl = rootDirResource.getURL();
if (equinoxResolveMethod != null) {
if (rootDirUrl.getProtocol().startsWith("bundle")) {
rootDirUrl = (URL) ReflectionUtils.invokeMethod(equinoxResolveMethod, null, rootDirUrl);
rootDirResource = new UrlResource(rootDirUrl);
}
}
if (rootDirUrl.getProtocol().startsWith(ResourceUtils.URL_PROTOCOL_VFS)) {
result.addAll(VfsResourceMatchingDelegate.findMatchingResources(rootDirUrl, subPattern, getPathMatcher()));
}
else if (ResourceUtils.isJarURL(rootDirUrl) || isJarResource(rootDirResource)) {
result.addAll(doFindPathMatchingJarResources(rootDirResource, rootDirUrl, subPattern));
}
else {
result.addAll(doFindPathMatchingFileResources(rootDirResource, subPattern));
}
}
if (logger.isDebugEnabled()) {
logger.debug("Resolved location pattern [" + locationPattern + "] to resources " + result);
}
return result.toArray(new Resource[result.size()]);
I'm now using embed jbpm 6.2 as my common service, so i write a jar which includes the jbpm service, and then i used a URL Classloader to load it, it runs pretty well, but after i closed the jbpm engine and try to remove the jars, there are some jars i can't remove.
here is the code to initialize the jbpm engine in the jar
try {
emf = Persistence.createEntityManagerFactory(Constants.JBPM_JPA_UNIT_NAME);
DBUserGroupCallbackImpl callback = new DBUserGroupCallbackImpl(props);
RuntimeEnvironmentBuilder kBuilder = RuntimeEnvironmentBuilder.getDefault()
.classLoader(this.getClass().getClassLoader())
.entityManagerFactory(emf)
.userGroupCallback(callback)
.persistence(true);
String path = props.getProperty(Constants.BPMN_RESOURCE_PATH);
logger.debug("Get bpmn resource with path = {}", path);
if (!StringUtil.isEmpty(path)) {
String[] paths = path.split(";");
List<File> files = getFile(paths);
if (files != null && !files.isEmpty()) {
List<Resource> resources = getResource(files);
if (resources != null && !resources.isEmpty()) {
for (Resource resource : resources) {
kBuilder.addAsset(resource, ResourceType.BPMN2);
logger.info("Add asset to jbpm success, resource = {}", resource);
}
}
}
}
runtimeManager = RuntimeManagerFactory.Factory.get().newSingletonRuntimeManager(kBuilder.get());
runtime = runtimeManager.getRuntimeEngine(EmptyContext.get());
this.kiesession = runtime.getKieSession();
this.taskService = runtime.getTaskService();
here is the code to close the jbpm engine:
public void close() {
if (runtimeManager != null) {
runtimeManager.disposeRuntimeEngine(runtime);
runtimeManager.close();
}
if (kiesession != null) {
kiesession.destroy();
}
if (emf != null) {
emf.close();
}
}
Now i use the code like below to remove the jars:
jbpmService.close();
urlcloassloader.close();
System.gc();
// waiting 1min
FileUtil.forceDelete(dir)
Most of the jars has been removed, but i can't remove the drools-core-6.2.0.Final.jar and postgresql-42.0.0.jre7.jar, is anybody know why?
I have a java web application working on struts. I want to access the data in the struts-config.xml file in runtime.
I tried to access it like a simple file, but it's unreachable to the application because it's outside the root directory of the app.
How does struts itself read the file? And how can I immitate it in runtime? I just need to read it like a simple xml file.
Thanks.
Struts does this simply by using ServletContext.
Because Struts ActionServlet extends HttpServlet, they simply do:
URL resource = getServletContext().getResource("/WEB-INF/struts-config.xml");
From there, You can get an InputStream and read the data from the resource.
Should the resource be null, the other alternative would be:
ClassLoader loader = Thread.currentThread().getContextClassLoader();
if (loader == null) {
loader = this.getClass().getClassLoader();
}
Enumeration e = loader.getResources(path);
if (e != null && e.hasMoreElements()) {
resource = (URL)e.nextElement();
}
The codes above is just simplified.
In Stuts2, method init_TraditionalXmlConfigurations in class org.apache.struts2.dispatcher.Dispatcher is responsible to init xml configurations. It will search 3 files, struts-default.xml,struts-plugin.xml,struts.xml(they are defined in constant variant DEFAULT_CONFIGURATION_PATHS).
private void init_TraditionalXmlConfigurations() {
String configPaths = initParams.get("config");
if (configPaths == null) {
configPaths = DEFAULT_CONFIGURATION_PATHS;
}
String[] files = configPaths.split("\\s*[,]\\s*");
for (String file : files) {
if (file.endsWith(".xml")) {
if ("xwork.xml".equals(file)) {
configurationManager.addContainerProvider(createXmlConfigurationProvider(file, false));
} else {
configurationManager.addContainerProvider(createStrutsXmlConfigurationProvider(file, false, servletContext));
}
} else {
throw new IllegalArgumentException("Invalid configuration file name");
}
}
}
Then, in method loadConfigurationFiles, it will get all configuration files url:
try {
urls = getConfigurationUrls(fileName);
} catch (IOException ex) {
ioException = ex;
}
And the following implementation is how to get configuration files' url:
protected Iterator<URL> getConfigurationUrls(String fileName) throws IOException {
return ClassLoaderUtil.getResources(fileName, XmlConfigurationProvider.class, false);
}
public static Iterator<URL> getResources(String resourceName, Class callingClass, boolean aggregate) throws IOException {
AggregateIterator<URL> iterator = new AggregateIterator<URL>();
iterator.addEnumeration(Thread.currentThread().getContextClassLoader().getResources(resourceName));
if (!iterator.hasNext() || aggregate) {
iterator.addEnumeration(ClassLoaderUtil.class.getClassLoader().getResources(resourceName));
}
if (!iterator.hasNext() || aggregate) {
ClassLoader cl = callingClass.getClassLoader();
if (cl != null) {
iterator.addEnumeration(cl.getResources(resourceName));
}
}
if (!iterator.hasNext() && (resourceName != null) && ((resourceName.length() == 0) || (resourceName.charAt(0) != '/'))) {
return getResources('/' + resourceName, callingClass, aggregate);
}
return iterator;
}
The code above is how struts loads configuration.
For you, if you want to load struts-config.xml manually, you can use the following code:
String filePath = "your struts-config.xml file path";
URL resource = Thread.currentThread().getContextClassLoader().getResource(filePath);
Then, you can read the file like a simple xml file.
I have this code which reads all the files from a directory.
File textFolder = new File("text_directory");
File [] texFiles = textFolder.listFiles( new FileFilter() {
public boolean accept( File file ) {
return file.getName().endsWith(".txt");
}
});
It works great. It fills the array with all the files that end with ".txt" from directory "text_directory".
How can I read the contents of a directory in a similar fashion within a JAR file?
So what I really want to do is, to list all the images inside my JAR file, so I can load them with:
ImageIO.read(this.getClass().getResource("CompanyLogo.png"));
(That one works because the "CompanyLogo" is "hardcoded" but the number of images inside the JAR file could be from 10 to 200 variable length.)
EDIT
So I guess my main problem would be: How to know the name of the JAR file where my main class lives?
Granted I could read it using java.util.Zip.
My Structure is like this:
They are like:
my.jar!/Main.class
my.jar!/Aux.class
my.jar!/Other.class
my.jar!/images/image01.png
my.jar!/images/image02a.png
my.jar!/images/imwge034.png
my.jar!/images/imagAe01q.png
my.jar!/META-INF/manifest
Right now I'm able to load for instance "images/image01.png" using:
ImageIO.read(this.getClass().getResource("images/image01.png));
But only because I know the file name, for the rest I have to load them dynamically.
CodeSource src = MyClass.class.getProtectionDomain().getCodeSource();
if (src != null) {
URL jar = src.getLocation();
ZipInputStream zip = new ZipInputStream(jar.openStream());
while(true) {
ZipEntry e = zip.getNextEntry();
if (e == null)
break;
String name = e.getName();
if (name.startsWith("path/to/your/dir/")) {
/* Do something with this entry. */
...
}
}
}
else {
/* Fail... */
}
Note that in Java 7, you can create a FileSystem from the JAR (zip) file, and then use NIO's directory walking and filtering mechanisms to search through it. This would make it easier to write code that handles JARs and "exploded" directories.
Code that works for both IDE's and .jar files:
import java.io.*;
import java.net.*;
import java.nio.file.*;
import java.util.*;
import java.util.stream.*;
public class ResourceWalker {
public static void main(String[] args) throws URISyntaxException, IOException {
URI uri = ResourceWalker.class.getResource("/resources").toURI();
Path myPath;
if (uri.getScheme().equals("jar")) {
FileSystem fileSystem = FileSystems.newFileSystem(uri, Collections.<String, Object>emptyMap());
myPath = fileSystem.getPath("/resources");
} else {
myPath = Paths.get(uri);
}
Stream<Path> walk = Files.walk(myPath, 1);
for (Iterator<Path> it = walk.iterator(); it.hasNext();){
System.out.println(it.next());
}
}
}
erickson's answer worked perfectly:
Here's the working code.
CodeSource src = MyClass.class.getProtectionDomain().getCodeSource();
List<String> list = new ArrayList<String>();
if( src != null ) {
URL jar = src.getLocation();
ZipInputStream zip = new ZipInputStream( jar.openStream());
ZipEntry ze = null;
while( ( ze = zip.getNextEntry() ) != null ) {
String entryName = ze.getName();
if( entryName.startsWith("images") && entryName.endsWith(".png") ) {
list.add( entryName );
}
}
}
webimages = list.toArray( new String[ list.size() ] );
And I have just modify my load method from this:
File[] webimages = ...
BufferedImage image = ImageIO.read(this.getClass().getResource(webimages[nextIndex].getName() ));
To this:
String [] webimages = ...
BufferedImage image = ImageIO.read(this.getClass().getResource(webimages[nextIndex]));
I would like to expand on acheron55's answer, since it is a very non-safe solution, for several reasons:
It doesn't close the FileSystem object.
It doesn't check if the FileSystem object already exists.
It isn't thread-safe.
This is somewhat a safer solution:
private static ConcurrentMap<String, Object> locks = new ConcurrentHashMap<>();
public void walk(String path) throws Exception {
URI uri = getClass().getResource(path).toURI();
if ("jar".equals(uri.getScheme()) {
safeWalkJar(path, uri);
} else {
Files.walk(Paths.get(path));
}
}
private void safeWalkJar(String path, URI uri) throws Exception {
synchronized (getLock(uri)) {
// this'll close the FileSystem object at the end
try (FileSystem fs = getFileSystem(uri)) {
Files.walk(fs.getPath(path));
}
}
}
private Object getLock(URI uri) {
String fileName = parseFileName(uri);
locks.computeIfAbsent(fileName, s -> new Object());
return locks.get(fileName);
}
private String parseFileName(URI uri) {
String schemeSpecificPart = uri.getSchemeSpecificPart();
return schemeSpecificPart.substring(0, schemeSpecificPart.indexOf("!"));
}
private FileSystem getFileSystem(URI uri) throws IOException {
try {
return FileSystems.getFileSystem(uri);
} catch (FileSystemNotFoundException e) {
return FileSystems.newFileSystem(uri, Collections.<String, String>emptyMap());
}
}
There's no real need to synchronize over the file name; one could simply synchronize on the same object every time (or make the method synchronized), it's purely an optimization.
I would say that this is still a problematic solution, since there might be other parts in the code that use the FileSystem interface over the same files, and it could interfere with them (even in a single threaded application).
Also, it doesn't check for nulls (for instance, on getClass().getResource().
This particular Java NIO interface is kind of horrible, since it introduces a global/singleton non thread-safe resource, and its documentation is extremely vague (a lot of unknowns due to provider specific implementations). Results may vary for other FileSystem providers (not JAR). Maybe there's a good reason for it being that way; I don't know, I haven't researched the implementations.
So I guess my main problem would be, how to know the name of the jar where my main class lives.
Assuming that your project is packed in a Jar (not necessarily true!), you can use ClassLoader.getResource() or findResource() with the class name (followed by .class) to get the jar that contains a given class. You'll have to parse the jar name from the URL that gets returned (not that tough), which I will leave as an exercise for the reader :-)
Be sure to test for the case where the class is not part of a jar.
I've ported acheron55's answer to Java 7 and closed the FileSystem object. This code works in IDE's, in jar files and in a jar inside a war on Tomcat 7; but note that it does not work in a jar inside a war on JBoss 7 (it gives FileSystemNotFoundException: Provider "vfs" not installed, see also this post). Furthermore, like the original code, it is not thread safe, as suggested by errr. For these reasons I have abandoned this solution; however, if you can accept these issues, here is my ready-made code:
import java.io.IOException;
import java.net.*;
import java.nio.file.*;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.Collections;
public class ResourceWalker {
public static void main(String[] args) throws URISyntaxException, IOException {
URI uri = ResourceWalker.class.getResource("/resources").toURI();
System.out.println("Starting from: " + uri);
try (FileSystem fileSystem = (uri.getScheme().equals("jar") ? FileSystems.newFileSystem(uri, Collections.<String, Object>emptyMap()) : null)) {
Path myPath = Paths.get(uri);
Files.walkFileTree(myPath, new SimpleFileVisitor<Path>() {
#Override
public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
System.out.println(file);
return FileVisitResult.CONTINUE;
}
});
}
}
}
Here is an example of using Reflections library to recursively scan classpath by regex name pattern augmented with a couple of Guava perks to to fetch resources contents:
Reflections reflections = new Reflections("com.example.package", new ResourcesScanner());
Set<String> paths = reflections.getResources(Pattern.compile(".*\\.template$"));
Map<String, String> templates = new LinkedHashMap<>();
for (String path : paths) {
log.info("Found " + path);
String templateName = Files.getNameWithoutExtension(path);
URL resource = getClass().getClassLoader().getResource(path);
String text = Resources.toString(resource, StandardCharsets.UTF_8);
templates.put(templateName, text);
}
This works with both jars and exploded classes.
Here's a method I wrote for a "run all JUnits under a package". You should be able to adapt it to your needs.
private static void findClassesInJar(List<String> classFiles, String path) throws IOException {
final String[] parts = path.split("\\Q.jar\\\\E");
if (parts.length == 2) {
String jarFilename = parts[0] + ".jar";
String relativePath = parts[1].replace(File.separatorChar, '/');
JarFile jarFile = new JarFile(jarFilename);
final Enumeration<JarEntry> entries = jarFile.entries();
while (entries.hasMoreElements()) {
final JarEntry entry = entries.nextElement();
final String entryName = entry.getName();
if (entryName.startsWith(relativePath)) {
classFiles.add(entryName.replace('/', File.separatorChar));
}
}
}
}
Edit:
Ah, in that case, you might want this snippet as well (same use case :) )
private static File findClassesDir(Class<?> clazz) {
try {
String path = clazz.getProtectionDomain().getCodeSource().getLocation().getFile();
final String codeSourcePath = URLDecoder.decode(path, "UTF-8");
final String thisClassPath = new File(codeSourcePath, clazz.getPackage().getName().repalce('.', File.separatorChar));
} catch (UnsupportedEncodingException e) {
throw new AssertionError("impossible", e);
}
}
Just to mention that if you are already using Spring, you can take advantage of the PathMatchingResourcePatternResolver.
For instance to get all the PNG files from a images folder in resources
ClassLoader cl = this.getClass().getClassLoader();
ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver(cl);
Resource[] resources = resolver.getResources("images/*.png");
for (Resource r: resources){
logger.info(r.getFilename());
// From your example
// ImageIO.read(cl.getResource("images/" + r.getFilename()));
}
A jar file is just a zip file with a structured manifest. You can open the jar file with the usual java zip tools and scan the file contents that way, inflate streams, etc. Then use that in a getResourceAsStream call, and it should be all hunky dory.
EDIT / after clarification
It took me a minute to remember all the bits and pieces and I'm sure there are cleaner ways to do it, but I wanted to see that I wasn't crazy. In my project image.jpg is a file in some part of the main jar file. I get the class loader of the main class (SomeClass is the entry point) and use it to discover the image.jpg resource. Then some stream magic to get it into this ImageInputStream thing and everything is fine.
InputStream inputStream = SomeClass.class.getClassLoader().getResourceAsStream("image.jpg");
JPEGImageReaderSpi imageReaderSpi = new JPEGImageReaderSpi();
ImageReader ir = imageReaderSpi.createReaderInstance();
ImageInputStream iis = new MemoryCacheImageInputStream(inputStream);
ir.setInput(iis);
....
ir.read(0); //will hand us a buffered image
Given an actual JAR file, you can list the contents using JarFile.entries(). You will need to know the location of the JAR file though - you can't just ask the classloader to list everything it could get at.
You should be able to work out the location of the JAR file based on the URL returned from ThisClassName.class.getResource("ThisClassName.class"), but it may be a tiny bit fiddly.
Some time ago I made a function that gets classess from inside JAR:
public static Class[] getClasses(String packageName)
throws ClassNotFoundException{
ArrayList<Class> classes = new ArrayList<Class> ();
packageName = packageName.replaceAll("\\." , "/");
File f = new File(jarName);
if(f.exists()){
try{
JarInputStream jarFile = new JarInputStream(
new FileInputStream (jarName));
JarEntry jarEntry;
while(true) {
jarEntry=jarFile.getNextJarEntry ();
if(jarEntry == null){
break;
}
if((jarEntry.getName ().startsWith (packageName)) &&
(jarEntry.getName ().endsWith (".class")) ) {
classes.add(Class.forName(jarEntry.getName().
replaceAll("/", "\\.").
substring(0, jarEntry.getName().length() - 6)));
}
}
}
catch( Exception e){
e.printStackTrace ();
}
Class[] classesA = new Class[classes.size()];
classes.toArray(classesA);
return classesA;
}else
return null;
}
public static ArrayList<String> listItems(String path) throws Exception{
InputStream in = ClassLoader.getSystemClassLoader().getResourceAsStream(path);
byte[] b = new byte[in.available()];
in.read(b);
String data = new String(b);
String[] s = data.split("\n");
List<String> a = Arrays.asList(s);
ArrayList<String> m = new ArrayList<>(a);
return m;
}
There are two very useful utilities both called JarScan:
www.inetfeedback.com/jarscan
jarscan.dev.java.net
See also this question: JarScan, scan all JAR files in all subfolders for specific class
The most robust mechanism for listing all resources in the classpath is currently to use this pattern with ClassGraph, because it handles the widest possible array of classpath specification mechanisms, including the new JPMS module system. (I am the author of ClassGraph.)
How to know the name of the JAR file where my main class lives?
URI mainClasspathElementURI;
try (ScanResult scanResult = new ClassGraph().whitelistPackages("x.y.z")
.enableClassInfo().scan()) {
mainClasspathElementURI =
scanResult.getClassInfo("x.y.z.MainClass").getClasspathElementURI();
}
How can I read the contents of a directory in a similar fashion within a JAR file?
List<String> classpathElementResourcePaths;
try (ScanResult scanResult = new ClassGraph().overrideClasspath(mainClasspathElementURI)
.scan()) {
classpathElementResourcePaths = scanResult.getAllResources().getPaths();
}
There are lots of other ways to deal with resources too.
One more for the road that's a bit more flexible for matching specific filenames because it uses wildcard globbing. In a functional style this could resemble:
import java.io.IOException;
import java.net.URISyntaxException;
import java.nio.file.FileSystem;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.function.Consumer;
import static java.nio.file.FileSystems.getDefault;
import static java.nio.file.FileSystems.newFileSystem;
import static java.util.Collections.emptyMap;
/**
* Responsible for finding file resources.
*/
public class ResourceWalker {
/**
* Globbing pattern to match font names.
*/
public static final String GLOB_FONTS = "**.{ttf,otf}";
/**
* #param directory The root directory to scan for files matching the glob.
* #param c The consumer function to call for each matching path
* found.
* #throws URISyntaxException Could not convert the resource to a URI.
* #throws IOException Could not walk the tree.
*/
public static void walk(
final String directory, final String glob, final Consumer<Path> c )
throws URISyntaxException, IOException {
final var resource = ResourceWalker.class.getResource( directory );
final var matcher = getDefault().getPathMatcher( "glob:" + glob );
if( resource != null ) {
final var uri = resource.toURI();
final Path path;
FileSystem fs = null;
if( "jar".equals( uri.getScheme() ) ) {
fs = newFileSystem( uri, emptyMap() );
path = fs.getPath( directory );
}
else {
path = Paths.get( uri );
}
try( final var walk = Files.walk( path, 10 ) ) {
for( final var it = walk.iterator(); it.hasNext(); ) {
final Path p = it.next();
if( matcher.matches( p ) ) {
c.accept( p );
}
}
} finally {
if( fs != null ) { fs.close(); }
}
}
}
}
Consider parameterizing the file extensions, left an exercise for the reader.
Be careful with Files.walk. According to the documentation:
This method must be used within a try-with-resources statement or similar control structure to ensure that the stream's open directories are closed promptly after the stream's operations have completed.
Likewise, newFileSystem must be closed, but not before the walker has had a chance to visit the file system paths.
Just a different way of listing/reading files from a jar URL and it does it recursively for nested jars
https://gist.github.com/trung/2cd90faab7f75b3bcbaa
URL urlResource = Thead.currentThread().getContextClassLoader().getResource("foo");
JarReader.read(urlResource, new InputStreamCallback() {
#Override
public void onFile(String name, InputStream is) throws IOException {
// got file name and content stream
}
});