Class PathMatchingResourcePatternResolver

java.lang.Object
org.springframework.core.io.support.PathMatchingResourcePatternResolver
All Implemented Interfaces:
ResourceLoader, ResourcePatternResolver
Direct Known Subclasses:
ServletContextResourcePatternResolver
public class PathMatchingResourcePatternResolver extends Object implements ResourcePatternResolver
A ResourcePatternResolver implementation that is able to resolve a specified resource location path into one or more matching Resources.

The source path may be a simple path which has a one-to-one mapping to a target Resource, or alternatively may contain the special "classpath*:" prefix and/or internal Ant-style path patterns (matched using Spring's AntPathMatcher utility). Both of the latter are effectively wildcards.

No Wildcards

In the simple case, if the specified location path does not start with the "classpath*:" prefix and does not contain a PathMatcher pattern, this resolver will simply return a single resource via a getResource() call on the underlying ResourceLoader. Examples are real URLs such as "file:C:/context.xml", pseudo-URLs such as "classpath:/context.xml", and simple unprefixed paths such as "/WEB-INF/context.xml". The latter will resolve in a fashion specific to the underlying ResourceLoader (for example, ServletContextResource for a WebApplicationContext).

Ant-style Patterns

When the path location contains an Ant-style pattern, for example: 

/WEB-INF/*-context.xml
com/example/**/applicationContext.xml
file:C:/some/path/*-context.xml
classpath:com/example/**/applicationContext.xml
the resolver follows a more complex but defined procedure to try to resolve the wildcard. It produces a Resource for the path up to the last non-wildcard segment and obtains a URL from it. If this URL is not a "jar:" URL or container-specific variant (for example, "zip:" in WebLogic, "wsjar" in WebSphere", etc.), then the root directory of the filesystem associated with the URL is obtained and used to resolve the wildcards by walking the filesystem. In the case of a jar URL, the resolver either gets a java.net.JarURLConnection from it, or manually parses the jar URL, and then traverses the contents of the jar file, to resolve the wildcards.

Implications on Portability

If the specified path is already a file URL (either explicitly, or implicitly because the base ResourceLoader is a filesystem one), then wildcarding is guaranteed to work in a completely portable fashion.

If the specified path is a class path location, then the resolver must obtain the last non-wildcard path segment URL via a Classloader.getResource() call. Since this is just a node of the path (not the file at the end) it is actually undefined (in the ClassLoader Javadocs) exactly what sort of URL is returned in this case. In practice, it is usually a java.io.File representing the directory, where the class path resource resolves to a filesystem location, or a jar URL of some sort, where the class path resource resolves to a jar location. Still, there is a portability concern on this operation.

If a jar URL is obtained for the last non-wildcard segment, the resolver must be able to get a java.net.JarURLConnection from it, or manually parse the jar URL, to be able to walk the contents of the jar and resolve the wildcard. This will work in most environments but will fail in others, and it is strongly recommended that the wildcard resolution of resources coming from jars be thoroughly tested in your specific environment before you rely on it.

classpath*: Prefix

There is special support for retrieving multiple class path resources with the same name, via the "classpath*:" prefix. For example, "classpath*:META-INF/beans.xml" will find all "META-INF/beans.xml" files in the class path, be it in "classes" directories or in JAR files. This is particularly useful for autodetecting config files of the same name at the same location within each jar file. Internally, this happens via a ClassLoader.getResources() call, and is completely portable.

The "classpath*:" prefix can also be combined with a PathMatcher pattern in the rest of the location path — for example, "classpath*:META-INF/*-beans.xml". In this case, the resolution strategy is fairly simple: a ClassLoader.getResources() call is used on the last non-wildcard path segment to get all the matching resources in the class loader hierarchy, and then off each resource the same PathMatcher resolution strategy described above is used for the wildcard sub pattern.

Other Notes

As of Spring Framework 6.0, if getResources(String) is invoked with a location pattern using the "classpath*:" prefix it will first search all modules in the boot layer, excluding system modules. It will then search the class path using ClassLoader APIs as described previously and return the combined results. Consequently, some of the limitations of class path searches may not apply when applications are deployed as modules.

WARNING: Note that "classpath*:" when combined with Ant-style patterns will only work reliably with at least one root directory before the pattern starts, unless the actual target files reside in the file system. This means that a pattern like "classpath*:*.xml" will not retrieve files from the root of jar files but rather only from the root of expanded directories. This originates from a limitation in the JDK's ClassLoader.getResources() method which only returns file system locations for a passed-in empty String (indicating potential roots to search). This ResourcePatternResolver implementation tries to mitigate the jar root lookup limitation through URLClassLoader introspection and "java.class.path" manifest evaluation; however, without portability guarantees.

WARNING: Ant-style patterns with "classpath:" resources are not guaranteed to find matching resources if the base package to search is available in multiple class path locations. This is because a resource such as 

  com/example/package1/service-context.xml
may exist in only one class path location, but when a location pattern such as 
  classpath:com/example/**/service-context.xml
is used to try to resolve it, the resolver will work off the (first) URL returned by getResource("com/example"). If the com/example base package node exists in multiple class path locations, the actual desired resource may not be present under the com/example base package in the first URL. Therefore, preferably, use "classpath*:" with the same Ant-style pattern in such a case, which will search all class path locations that contain the base package.
Since:
1.0.2
Author:
Juergen Hoeller, Colin Sampaleanu, Marius Bogoevici, Costin Leau, Phillip Webb, Sam Brannen, Sebastien Deleuze, Dave Syer
See Also:

  • Constructor Details

    • PathMatchingResourcePatternResolver

      public PathMatchingResourcePatternResolver()
      Create a PathMatchingResourcePatternResolver with a DefaultResourceLoader.

      ClassLoader access will happen via the thread context class loader.

      See Also:

    • PathMatchingResourcePatternResolver

      public PathMatchingResourcePatternResolver(ResourceLoader resourceLoader)
      Create a PathMatchingResourcePatternResolver with the supplied ResourceLoader.

      ClassLoader access will happen via the thread context class loader.

      Parameters:
      resourceLoader - the ResourceLoader to load root directories and actual resources with

    • PathMatchingResourcePatternResolver

      public PathMatchingResourcePatternResolver(@Nullable ClassLoader classLoader)
      Create a PathMatchingResourcePatternResolver with a DefaultResourceLoader and the supplied ClassLoader.
      Parameters:
      classLoader - the ClassLoader to load class path resources with, or null for using the thread context class loader at the time of actual resource access
      See Also:

  • Method Details

    • getResourceLoader

      public ResourceLoader getResourceLoader()
      Return the ResourceLoader that this pattern resolver works with.

    • getClassLoader

      public @Nullable ClassLoader getClassLoader()
      Description copied from interface: ResourceLoader
      Expose the ClassLoader used by this ResourceLoader.

      Clients which need to access the ClassLoader directly can do so in a uniform manner with the ResourceLoader, rather than relying on the thread context ClassLoader.

      Specified by:
      getClassLoader in interface ResourceLoader
      Returns:
      the ClassLoader (only null if even the system ClassLoader isn't accessible)
      See Also:

    • setPathMatcher

      public void setPathMatcher(PathMatcher pathMatcher)
      Set the PathMatcher implementation to use for this resource pattern resolver.

      Default is AntPathMatcher.

      See Also:

    • getPathMatcher

      public PathMatcher getPathMatcher()
      Return the PathMatcher that this resource pattern resolver uses.

    • setUseCaches

      public void setUseCaches(boolean useCaches)
      Specify whether this resolver should use jar caches. Default is true.

      Switch this flag to false in order to avoid any jar caching, at the JarURLConnection level as well as within this resolver instance.

      Note that URLConnection.setDefaultUseCaches(boolean) can be turned off independently. This resolver-level setting is designed to only enforce JarURLConnection#setUseCaches(true/false) if necessary but otherwise leaves the JVM-level default in place (if this setter has not been called).

      As of 6.2.10, this setting propagates to UrlResource.setUseCaches(boolean).

      Since:
      6.1.19
      See Also:

    • getResource

      public Resource getResource(String location)
      Description copied from interface: ResourceLoader
      Return a Resource handle for the specified resource location.

      The handle should always be a reusable resource descriptor, allowing for multiple InputStreamSource.getInputStream() calls.

      • Must support fully qualified URLs, for example, "file:C:/test.dat".
      • Must support classpath pseudo-URLs, for example, "classpath:test.dat".
      • Should support relative file paths, for example, "WEB-INF/test.dat". (This will be implementation-specific, typically provided by an ApplicationContext implementation.)

      Note that a Resource handle does not imply an existing resource; you need to invoke Resource.exists() to check for existence.

      Specified by:
      getResource in interface ResourceLoader
      Parameters:
      location - the resource location
      Returns:
      a corresponding Resource handle (never null)
      See Also:

    • getResources

      public Resource[] getResources(String locationPattern) throws IOException
      Description copied from interface: ResourcePatternResolver
      Resolve the given location pattern into Resource objects.

      Overlapping resource entries that point to the same physical resource should be avoided, as far as possible. The result should have set semantics.

      Specified by:
      getResources in interface ResourcePatternResolver
      Parameters:
      locationPattern - the location pattern to resolve
      Returns:
      the corresponding Resource objects
      Throws:
      IOException - in case of I/O errors

    • clearCache

      public void clearCache()
      Clear the local resource cache, removing all cached classpath/jar structures.
      Since:
      6.2

    • findAllClassPathResources

      protected Resource[] findAllClassPathResources(String location) throws IOException
      Find all class location resources with the given location via the ClassLoader.

      Delegates to doFindAllClassPathResources(String).

      Parameters:
      location - the absolute path within the class path
      Returns:
      the result as Resource array
      Throws:
      IOException - in case of I/O errors
      See Also:

    • doFindAllClassPathResources

      protected Set<Resource> doFindAllClassPathResources(String path) throws IOException
      Find all class path resources with the given path via the configured ClassLoader.

      Called by findAllClassPathResources(String).

      Parameters:
      path - the absolute path within the class path (never a leading slash)
      Returns:
      a mutable Set of matching Resource instances
      Throws:
      IOException
      Since:
      4.1.1

    • convertClassLoaderURL

      protected Resource convertClassLoaderURL(URL url)
      Convert the given URL as returned from the configured ClassLoader into a Resource, applying to path lookups without a pattern (see findAllClassPathResources(String)).

      As of 6.0.5, the default implementation creates a FileSystemResource in case of the "file" protocol or a UrlResource otherwise, matching the outcome of pattern-based class path traversal in the same resource layout, as well as matching the outcome of module path searches.

      Parameters:
      url - a URL as returned from the configured ClassLoader
      Returns:
      the corresponding Resource object
      See Also:

    • addAllClassLoaderJarRoots

      protected void addAllClassLoaderJarRoots(@Nullable ClassLoader classLoader, Set<Resource> result)
      Search all URLClassLoader URLs for jar file references and add each to the given set of resources in the form of a pointer to the root of the jar file content.
      Parameters:
      classLoader - the ClassLoader to search (including its ancestors)
      result - the set of resources to add jar roots to
      Since:
      4.1.1

    • addClassPathManifestEntries

      protected void addClassPathManifestEntries(Set<Resource> result)
      Determine jar file references from Class-Path manifest entries (which are added to the java.class.path JVM system property by the system class loader) and add each to the given set of resources in the form of a pointer to the root of the jar file content.
      Parameters:
      result - the set of resources to add jar roots to
      Since:
      4.3

    • findPathMatchingResources

      protected Resource[] findPathMatchingResources(String locationPattern) throws IOException
      Find all resources that match the given location pattern via the Ant-style PathMatcher.

      Supports resources in OSGi bundles, JBoss VFS, jar files, zip files, and file systems.

      Parameters:
      locationPattern - the location pattern to match
      Returns:
      the result as Resource array
      Throws:
      IOException - in case of I/O errors
      See Also:

    • determineRootDir

      protected String determineRootDir(String location)
      Determine the root directory for the given location.

      Used for determining the starting point for file matching, resolving the root directory location to be passed into getResources(String), with the remainder of the location to be used as the sub pattern.

      Will return "/WEB-INF/" for the location "/WEB-INF/*.xml", for example.

      Parameters:
      location - the location to check
      Returns:
      the part of the location that denotes the root directory
      See Also:

    • resolveRootDirResource

      protected Resource resolveRootDirResource(Resource original) throws IOException
      Resolve the supplied root directory resource for path matching.

      By default, findPathMatchingResources(String) resolves Equinox OSGi "bundleresource:" and "bundleentry:" URLs into standard jar file URLs that will be traversed using Spring's standard jar file traversal algorithm.

      For any custom resolution, override this template method and replace the supplied resource handle accordingly.

      The default implementation of this method returns the supplied resource unmodified.

      Parameters:
      original - the resource to resolve
      Returns:
      the resolved resource (may be identical to the supplied resource)
      Throws:
      IOException - in case of resolution failure
      See Also:

    • isJarResource

      protected boolean isJarResource(Resource resource) throws IOException
      Determine if the given resource handle indicates a jar resource that the doFindPathMatchingJarResources(Resource, URL, String) method can handle.

      findPathMatchingResources(String) delegates to ResourceUtils.isJarURL(URL) to determine whether the given URL points to a resource in a jar file, and only invokes this method as a fallback.

      This template method therefore allows for detecting further kinds of jar-like resources — for example, via instanceof checks on the resource handle type.

      The default implementation of this method returns false.

      Parameters:
      resource - the resource handle to check (usually the root directory to start path matching from)
      Returns:
      true if the given resource handle indicates a jar resource
      Throws:
      IOException - in case of I/O errors
      See Also:

    • doFindPathMatchingJarResources

      protected Set<Resource> doFindPathMatchingJarResources(Resource rootDirResource, URL rootDirUrl, String subPattern) throws IOException
      Find all resources in jar files that match the given location pattern via the Ant-style PathMatcher.
      Parameters:
      rootDirResource - the root directory as Resource
      rootDirUrl - the pre-resolved root directory URL
      subPattern - the sub pattern to match (below the root directory)
      Returns:
      a mutable Set of matching Resource instances
      Throws:
      IOException - in case of I/O errors
      Since:
      4.3
      See Also:

    • getJarFile

      protected JarFile getJarFile(String jarFileUrl) throws IOException
      Resolve the given jar file URL into a JarFile object.
      Throws:
      IOException

    • doFindPathMatchingFileResources

      protected Set<Resource> doFindPathMatchingFileResources(Resource rootDirResource, String subPattern) throws IOException
      Find all resources in the file system of the supplied root directory that match the given location sub pattern via the Ant-style PathMatcher.
      Parameters:
      rootDirResource - the root directory as a Resource
      subPattern - the sub pattern to match (below the root directory)
      Returns:
      a mutable Set of matching Resource instances
      Throws:
      IOException - in case of I/O errors
      See Also:

    • findAllModulePathResources

      protected Set<Resource> findAllModulePathResources(String locationPattern) throws IOException
      Resolve the given location pattern into Resource objects for all matching resources found in the module path.

      The location pattern may be an explicit resource path such as "com/example/config.xml" or a pattern such as "com/example/**/config-*.xml" to be matched using the configured PathMatcher.

      The default implementation scans all modules in the boot layer, excluding system modules.

      Parameters:
      locationPattern - the location pattern to resolve
      Returns:
      a modifiable Set containing the corresponding Resource objects
      Throws:
      IOException - in case of I/O errors
      Since:
      6.0
      See Also: