How to use ClassLoader getResources correctly

Question

How can I use ClassLoader getResources   to find recursivly resources from my classpath   E g     finding all resources in the META-INF  directory   Imagine something like   getClass   getClassLoader   getResources  META-INF    Unfortunately  this does only retrieve an URL to exactly this  directory   all resources named bla xml  recursivly   getClass   getClassLoader   getResources  bla xml    But this returns an empty Enumeration    And as a bonus question  How does ClassLoader getResources   differ from ClassLoader getResource

User · Accepted Answer

There is no way to recursively search through the classpath. You need to know the Full pathname of a resource to be able to retrieve it in this way. The resource may be in a directory in the file system or in a jar file so it is not as simple as performing a directory listing of "the classpath". You will need to provide the full path of the resource e.g. '/com/mypath/bla.xml'.

For your second question, getResource will return the first resource that matches the given resource name. The order that the class path is searched is given in the javadoc for getResource.

User · Answer

This is the simplest wat to get the File object to which a certain URL object is pointing at   File file new File url toURI       Now  for your concrete questions         finding all resources in the META-INF  directory        You can indeed get the File object pointing to this URL  Enumeration lt URL gt  en getClass   getClassLoader   getResources  META-INF    if  en hasMoreElements          URL metaInf en nextElement        File fileMetaInf new File metaInf toURI          File   files fileMetaInf listFiles          or      String   filenames fileMetaInf list              all resources named bla xml    recursivly       In this case  you ll have to do some custom code  Here is a dummy example   final List lt File gt  foundFiles new ArrayList lt File gt      FileFilter customFilter new FileFilter          Override     public boolean accept File pathname             if pathname isDirectory                  pathname listFiles this                     if pathname getName   endsWith  bla xml                  foundFiles add pathname               return true                    return false                    rootFolder here represents a File Object pointing the root forlder of your search  rootFolder listFiles customFilter     When the code is run  you ll get all the found ocurrences at the foundFiles List

User · Answer

MRalwasser  I d give you a hint  cast the URL getConnection   to JarURLConnection  Then use JarURLConnection getJarFile   and voila  You have the JarFile and you are free to access the resources inside   The rest I leave to you    Hope this helps

User · Answer

The Spring Framework has a class which allows to recursively search through the classpath   PathMatchingResourcePatternResolver resolver   new PathMatchingResourcePatternResolver    resolver getResources  classpath  some package name      xml

User · Answer

Here is code based on bestsss  answer       Enumeration lt URL gt  en   getClass   getClassLoader   getResources               META-INF        List lt String gt  profiles   new ArrayList lt  gt         while  en hasMoreElements              URL url   en nextElement            JarURLConnection urlcon    JarURLConnection   url openConnection             try  JarFile jar   urlcon getJarFile                   Enumeration lt JarEntry gt  entries   jar entries                while  entries hasMoreElements                      String entry   entries nextElement   getName                    System out println entry

[java] How to use ClassLoader.getResources() correctly?

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