Java Resource Path Get getExistingResourceAsFile(final String resourcePath)

Description

Create a java.io.File object for the input resourcePath argument.

License

Apache License

Declaration

public static final File getExistingResourceAsFile(final String resourcePath) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

import java.io.File;

import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;

public class Main {
    /**/*from   w  w  w . j  a va 2  s  . com*/
     * This is a file that must exist inside the main classpath resources directory, right now:
     * ".../sharp-editor/model-transform/src/main/resources/".  This code uses the Java Resource locator to
     * find this file in a machine-independent way, then uses the folder of this located file as the file
     * system folder to use as the root for locating other resource files.
     */
    private static final String knownRootResourcePath = "/FileInMainResourcesRoot.properties";
    /**
     * A configurable, alternate location to search for resources, if not found in the classpath.
     */
    public static File alternateResourceRootFolder = null;

    /**
     * Create a java.io.File object for the input resourcePath argument.  The resourcePath is a String value
     * relative to the main resources root folder, using '/' as the resourcePath separator character
     * (whether Windows or Unix file system).  An example value of resourcePath would be
     * "/ontologies/in/ClinicalDomainT.ofn".  Thus, if resource root is "..
     * ./sharp-editor/model-transform/src/main/resources/", then the File object will correspond to
     * ./sharp-editor/model-transform/src/main/resources/ontologies/in/ClinicalDomainT.ofn".
     *
     * The file does not have to exist for the File object to be successfully created.
     */
    public static final File getExistingResourceAsFile(final String resourcePath) {
        URL url = System.class.getResource(resourcePath);
        if (url != null) {
            try {
                return new File(url.toURI());
            } catch (URISyntaxException e) {
                //                e.printStackTrace();
            }
        }
        URL referenceURL = System.class.getResource(knownRootResourcePath);

        //        System.out.println( "referenceURL = " + referenceURL );

        if (referenceURL == null) {
            //            System.out.println( "Failed to find Resource in classpath: " + resourcePath + " trying alternatives... " );
            File altFile = getAlternateResourceFile(resourcePath);
            if (altFile != null) {
                return altFile;
            }
            final String message = "Not able to find root of Resources directory because method "
                    + "depends on finding known resource with resourcePath = '" + knownRootResourcePath + "'";
            RuntimeException e = new RuntimeException(message);
            e.printStackTrace();
            throw e;
        }
        try {
            URI rootURI = new File(referenceURL.toURI()).getParentFile().toURI();
            //            System.out.println(rootURI);
            final String fullPath = rootURI.toString() + resourcePath;
            URI fullURI = new URI(fullPath);
            File f = new File(fullURI);
            //            System.out.println( "fullPath to create URI = " + fullPath );
            //            System.out.println( "resource file = " + f );
            //            System.out.println( "Resource Root = " + knownResouceFile.getParentFile() );
            //            String fullPath = knownResouceFile.getParentFile().getAbsolutePath() + resourcePath;
            //            File f = new File( fullPath );

            return f;
        } catch (URISyntaxException e) {
            e.printStackTrace();

            return null;
        }
    }

    /**
     * An alternative to getExistingResourceAsFile() that takes a URI as input.  The input URI can either be
     * an absolute file URI (i.e., URI scheme = "file"), in which case the method will return a File for
     * that URI, or it can be a relative URI (no URI 'scheme'), in which case the File will be relative to
     * the resource root -- this method will delegate to getFileInTestResourceDir().
     */
    public static final File getExistingResourceAsFile(final URI uri) {
        if (uri == null) {
            return null;
        }
        String scheme = uri.getScheme();
        if (scheme != null && !"file".equals(scheme)) {
            return null;
        }
        if (uri.isAbsolute()) {
            //            System.out.println( "abs URI = " + uri );

            return new File(uri);
        } else {
            //            System.out.println( "uri.getPath() = " + uri.getPath() );

            return getExistingResourceAsFile(uri.getPath());
        }
    }

    public static File getAlternateResourceFile(final String resourcePath) {
        return getResourceFileRelativeToBase(alternateResourceRootFolder, resourcePath);
    }

    public static File getResourceFileRelativeToBase(final File baseDir, final String resourcePath) {

        final String baseDirUriString = baseDir != null ? baseDir.toURI().toString() : "file:/";
        final boolean baseEndsWithSlash = baseDirUriString.endsWith("/");
        final boolean resourcePathBeginsWithSlash = resourcePath.startsWith("/");
        final String uriString;
        if (baseEndsWithSlash != resourcePathBeginsWithSlash) {
            uriString = baseDirUriString + resourcePath;
        } else if (baseEndsWithSlash) {
            uriString = baseDirUriString.substring(0, baseDirUriString.length() - 1) + resourcePath;
        } else {
            uriString = baseDirUriString + "/" + resourcePath;
        }

        try {
            File f = new File(new URI(uriString));
            return f;
        } catch (URISyntaxException e) {
            e.printStackTrace();
            return null;
        }
    }
}

Related

1. getAlternateResourceFile(final String resourcePath)
2. getBasePath(Class clazz, String resource)
3. getChildResources(String path)
4. getClassResource(Class clazz, String resPath)
5. getClassResources(Class clazz, String resPath)
6. getFileFromBundle(String bundleName, String resourcePath)
7. getFileFromResource(Class clazz, String path)
8. getFileResourcePaths(final Class clazz, final String fileNameRegex)
9. getPath(final Object resource)