package com.ksa.util;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;

import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;

/**
* Utility methods for resolving resource locations to files in the
* file system. Mainly for internal use within the framework.
*
* <p>Consider using Spring's Resource abstraction in the core package
* for handling all kinds of file resources in a uniform manner.
* {@link org.springframework.core.io.ResourceLoader}'s <code>getResource</code>
* method can resolve any location to a {@link org.springframework.core.io.Resource}
* object, which in turn allows to obtain a <code>java.io.File</code> in the
* file system through its <code>getFile()</code> method.
*
* <p>The main reason for these utility methods for resource location handling
* is to support {@link Log4jConfigurer}, which must be able to resolve
* resource locations <i>before the logging system has been initialized</i>.
* Spring' Resource abstraction in the core package, on the other hand,
* already expects the logging system to be available.
*
* @author Juergen Hoeller
* @since 1.1.5
* @see org.springframework.core.io.Resource
* @see org.springframework.core.io.ClassPathResource
* @see org.springframework.core.io.FileSystemResource
* @see org.springframework.core.io.UrlResource
* @see org.springframework.core.io.ResourceLoader
*/
public abstract class ResourceUtils {

   /** Pseudo URL prefix for loading from the class path: "classpath:" */
   public static final String CLASSPATH_URL_PREFIX = "classpath:";

   /** URL prefix for loading from the file system: "file:" */
   public static final String FILE_URL_PREFIX = "file:";

   /** URL protocol for a file in the file system: "file" */
   public static final String URL_PROTOCOL_FILE = "file";

   /** URL protocol for an entry from a jar file: "jar" */
   public static final String URL_PROTOCOL_JAR = "jar";

   /** URL protocol for an entry from a zip file: "zip" */
   public static final String URL_PROTOCOL_ZIP = "zip";

   /** URL protocol for an entry from a JBoss jar file: "vfszip" */
   public static final String URL_PROTOCOL_VFSZIP = "vfszip";

   /** URL protocol for a JBoss VFS resource: "vfs" */
   public static final String URL_PROTOCOL_VFS = "vfs";

   /** URL protocol for an entry from a WebSphere jar file: "wsjar" */
   public static final String URL_PROTOCOL_WSJAR = "wsjar";

   /** URL protocol for an entry from an OC4J jar file: "code-source" */
   public static final String URL_PROTOCOL_CODE_SOURCE = "code-source";

   /** Separator between JAR URL and file path within the JAR */
   public static final String JAR_URL_SEPARATOR = "!/";


   /**
    * Return whether the given resource location is a URL:
    * either a special "classpath" pseudo URL or a standard URL.
    * @param resourceLocation the location String to check
    * @return whether the location qualifies as a URL
    * @see #CLASSPATH_URL_PREFIX
    * @see java.net.URL
    */
   public static boolean isUrl(String resourceLocation) {
       if (resourceLocation == null) {
           return false;
       }
       if (resourceLocation.startsWith(CLASSPATH_URL_PREFIX)) {
           return true;
       }
       try {
           new URL(resourceLocation);
           return true;
       }
       catch (MalformedURLException ex) {
           return false;
       }
   }

   /**
    * Resolve the given resource location to a <code>java.net.URL</code>.
    * <p>Does not check whether the URL actually exists; simply returns
    * the URL that the given location would correspond to.
    * @param resourceLocation the resource location to resolve: either a
    * "classpath:" pseudo URL, a "file:" URL, or a plain file path
    * @return a corresponding URL object
    * @throws FileNotFoundException if the resource cannot be resolved to a URL
    */
   public static URL getURL(String resourceLocation) throws FileNotFoundException {
       Assert.notNull(resourceLocation, "Resource location must not be null");
       if (resourceLocation.startsWith(CLASSPATH_URL_PREFIX)) {
           String path = resourceLocation.substring(CLASSPATH_URL_PREFIX.length());
           URL url = ClassUtils.getDefaultClassLoader().getResource(path);
           if (url == null) {
               String description = "class path resource [" + path + "]";
               throw new FileNotFoundException(
                       description + " cannot be resolved to URL because it does not exist");
           }
           return url;
       }
       try {
           // try URL
           return new URL(resourceLocation);
       }
       catch (MalformedURLException ex) {
           // no URL -> treat as file path
           try {
               return new File(resourceLocation).toURI().toURL();
           }
           catch (MalformedURLException ex2) {
               throw new FileNotFoundException("Resource location [" + resourceLocation +
                       "] is neither a URL not a well-formed file path");
           }
       }
   }

   /**
    * Resolve the given resource location to a <code>java.io.File</code>,
    * i.e. to a file in the file system.
    * <p>Does not check whether the fil actually exists; simply returns
    * the File that the given location would correspond to.
    * @param resourceLocation the resource location to resolve: either a
    * "classpath:" pseudo URL, a "file:" URL, or a plain file path
    * @return a corresponding File object
    * @throws FileNotFoundException if the resource cannot be resolved to
    * a file in the file system
    */
   public static File getFile(String resourceLocation) throws FileNotFoundException {
       Assert.notNull(resourceLocation, "Resource location must not be null");
       if (resourceLocation.startsWith(CLASSPATH_URL_PREFIX)) {
           String path = resourceLocation.substring(CLASSPATH_URL_PREFIX.length());
           String description = "class path resource [" + path + "]";
           URL url = ClassUtils.getDefaultClassLoader().getResource(path);
           if (url == null) {
               throw new FileNotFoundException(
                       description + " cannot be resolved to absolute file path " +
                       "because it does not reside in the file system");
           }
           return getFile(url, description);
       }
       try {
           // try URL
           return getFile(new URL(resourceLocation));
       }
       catch (MalformedURLException ex) {
           // no URL -> treat as file path
           return new File(resourceLocation);
       }
   }

   /**
    * Resolve the given resource URL to a <code>java.io.File</code>,
    * i.e. to a file in the file system.
    * @param resourceUrl the resource URL to resolve
    * @return a corresponding File object
    * @throws FileNotFoundException if the URL cannot be resolved to
    * a file in the file system
    */
   public static File getFile(URL resourceUrl) throws FileNotFoundException {
       return getFile(resourceUrl, "URL");
   }

   /**
    * Resolve the given resource URL to a <code>java.io.File</code>,
    * i.e. to a file in the file system.
    * @param resourceUrl the resource URL to resolve
    * @param description a description of the original resource that
    * the URL was created for (for example, a class path location)
    * @return a corresponding File object
    * @throws FileNotFoundException if the URL cannot be resolved to
    * a file in the file system
    */
   public static File getFile(URL resourceUrl, String description) throws FileNotFoundException {
       Assert.notNull(resourceUrl, "Resource URL must not be null");
       if (!URL_PROTOCOL_FILE.equals(resourceUrl.getProtocol())) {
           throw new FileNotFoundException(
                   description + " cannot be resolved to absolute file path " +
                   "because it does not reside in the file system: " + resourceUrl);
       }
       try {
           return new File(toURI(resourceUrl).getSchemeSpecificPart());
       }
       catch (URISyntaxException ex) {
           // Fallback for URLs that are not valid URIs (should hardly ever happen).
           return new File(resourceUrl.getFile());
       }
   }

   /**
    * Resolve the given resource URI to a <code>java.io.File</code>,
    * i.e. to a file in the file system.
    * @param resourceUri the resource URI to resolve
    * @return a corresponding File object
    * @throws FileNotFoundException if the URL cannot be resolved to
    * a file in the file system
    */
   public static File getFile(URI resourceUri) throws FileNotFoundException {
       return getFile(resourceUri, "URI");
   }

   /**
    * Resolve the given resource URI to a <code>java.io.File</code>,
    * i.e. to a file in the file system.
    * @param resourceUri the resource URI to resolve
    * @param description a description of the original resource that
    * the URI was created for (for example, a class path location)
    * @return a corresponding File object
    * @throws FileNotFoundException if the URL cannot be resolved to
    * a file in the file system
    */
   public static File getFile(URI resourceUri, String description) throws FileNotFoundException {
       Assert.notNull(resourceUri, "Resource URI must not be null");
       if (!URL_PROTOCOL_FILE.equals(resourceUri.getScheme())) {
           throw new FileNotFoundException(
                   description + " cannot be resolved to absolute file path " +
                   "because it does not reside in the file system: " + resourceUri);
       }
       return new File(resourceUri.getSchemeSpecificPart());
   }

   /**
    * Determine whether the given URL points to a resource in a jar file,
    * that is, has protocol "jar", "zip", "wsjar" or "code-source".
    * <p>"zip" and "wsjar" are used by BEA WebLogic Server and IBM WebSphere, respectively,
    * but can be treated like jar files. The same applies to "code-source" URLs on Oracle
    * OC4J, provided that the path contains a jar separator.
    * @param url the URL to check
    * @return whether the URL has been identified as a JAR URL
    */
   public static boolean isJarURL(URL url) {
       String protocol = url.getProtocol();
       return (URL_PROTOCOL_JAR.equals(protocol) ||
               URL_PROTOCOL_ZIP.equals(protocol) ||
               URL_PROTOCOL_WSJAR.equals(protocol) ||
               (URL_PROTOCOL_CODE_SOURCE.equals(protocol) && url.getPath().contains(JAR_URL_SEPARATOR)));
   }

   /**
    * Extract the URL for the actual jar file from the given URL
    * (which may point to a resource in a jar file or to a jar file itself).
    * @param jarUrl the original URL
    * @return the URL for the actual jar file
    * @throws MalformedURLException if no valid jar file URL could be extracted
    */
   public static URL extractJarFileURL(URL jarUrl) throws MalformedURLException {
       String urlFile = jarUrl.getFile();
       int separatorIndex = urlFile.indexOf(JAR_URL_SEPARATOR);
       if (separatorIndex != -1) {
           String jarFile = urlFile.substring(0, separatorIndex);
           try {
               return new URL(jarFile);
           }
           catch (MalformedURLException ex) {
               // Probably no protocol in original jar URL, like "jar:C:/mypath/myjar.jar".
               // This usually indicates that the jar file resides in the file system.
               if (!jarFile.startsWith("/")) {
                   jarFile = "/" + jarFile;
               }
               return new URL(FILE_URL_PREFIX + jarFile);
           }
       }
       else {
           return jarUrl;
       }
   }

   /**
    * Create a URI instance for the given URL,
    * replacing spaces with "%20" quotes first.
    * <p>Furthermore, this method works on JDK 1.4 as well,
    * in contrast to the <code>URL.toURI()</code> method.
    * @param url the URL to convert into a URI instance
    * @return the URI instance
    * @throws URISyntaxException if the URL wasn't a valid URI
    * @see java.net.URL#toURI()
    */
   public static URI toURI(URL url) throws URISyntaxException {
       return toURI(url.toString());
   }

   /**
    * Create a URI instance for the given location String,
    * replacing spaces with "%20" quotes first.
    * @param location the location String to convert into a URI instance
    * @return the URI instance
    * @throws URISyntaxException if the location wasn't a valid URI
    */
   public static URI toURI(String location) throws URISyntaxException {
       return new URI(StringUtils.replace(location, " ", "%20"));
   }
   
   
   /* ------- 自定义的工具方法 ------------------- */
   
   private static ResourcePatternResolver resourceLoader = new PathMatchingResourcePatternResolver();
   
   /**
    * Return a Resource handle for the specified resource.
    * The handle should always be a reusable resource descriptor,
    * allowing for multiple {@link Resource#getInputStream()} calls.
    * <p><ul>
    * <li>Must support fully qualified URLs, e.g. "file:C:/test.dat".
    * <li>Must support classpath pseudo-URLs, e.g. "classpath:test.dat".
    * (This will be implementation-specific, typically provided by an
    * ApplicationContext implementation.)
    * </ul>
    * <p>Note that a Resource handle does not imply an existing resource;
    * you need to invoke {@link Resource#exists} to check for existence.
    * @param location the resource location
    * @return a corresponding Resource handle
    * @see #CLASSPATH_URL_PREFIX
    * @see org.springframework.core.io.Resource#exists
    * @see org.springframework.core.io.Resource#getInputStream
    */
   public static Resource getResource( String resource ) {
       return resourceLoader.getResource( resource );
   }
   
   /**
    * Resolve the given location pattern into Resource objects.
    * <p>Overlapping resource entries that point to the same physical
    * resource should be avoided, as far as possible. The result should
    * have set semantics.
    * @param locationPattern the location pattern to resolve
    * @return the corresponding Resource objects
    * @throws IOException in case of I/O errors
    */
   public static Resource[] getResources( String resourcePattern ) throws IOException {
       return resourceLoader.getResources( resourcePattern );
   }

   
}

