package jef.tools.resource;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URL;
import java.net.URLConnection;
import java.util.LinkedList;
import java.util.List;
import jef.tools.Assert;
import jef.tools.ResourceUtils;
import jef.tools.StringUtils;
/**
* {@link Resource} implementation for <code>java.net.URL</code> locators.
* Obviously supports resolution as URL, and also as File in case of the "file:"
* protocol.
*
* @author Juergen Hoeller
* @since 28.12.2003
* @see java.net.URL
*/
public class UrlResource extends AbstractFileResolvingResource {
/**
* Original URL, used for actual access.
*/
private final URL url;
/**
* Cleaned URL (with normalized path), used for comparisons.
*/
private final URL cleanedUrl;
/**
* Original URI, if available; used for URI and File access.
*/
private final URI uri;
/**
* Create a new UrlResource.
*
* @param url
* a URL
*/
public UrlResource(URL url) {
Assert.notNull(url, "URL must not be null");
this.url = url;
this.cleanedUrl = getCleanedUrl(this.url, url.toString());
this.uri = null;
}
/**
* Create a new UrlResource.
*
* @param uri
* a URI
* @throws MalformedURLException
* if the given URL path is not valid
*/
public UrlResource(URI uri) throws MalformedURLException {
Assert.notNull(uri, "URI must not be null");
this.url = uri.toURL();
this.cleanedUrl = getCleanedUrl(this.url, uri.toString());
this.uri = uri;
}
/**
* Create a new UrlResource.
*
* @param path
* a URL path
* @throws MalformedURLException
* if the given URL path is not valid
*/
public UrlResource(String path) throws MalformedURLException {
Assert.notNull(path, "Path must not be null");
this.url = new URL(path);
this.cleanedUrl = getCleanedUrl(this.url, path);
this.uri = null;
}
/**
* Determine a cleaned URL for the given original URL.
*
* @param originalUrl
* the original URL
* @param originalPath
* the original URL path
* @return the cleaned URL
* @see org.springframework.util.StringUtils#cleanPath
*/
private URL getCleanedUrl(URL originalUrl, String originalPath) {
try {
return new URL(cleanPath(originalPath));
} catch (MalformedURLException ex) {
// Cleaned URL path cannot be converted to URL
// -> take original URL.
return originalUrl;
}
}
/**
* This implementation opens an InputStream for the given URL. It sets the
* "UseCaches" flag to <code>false</code>, mainly to avoid jar file locking
* on Windows.
*
* @see java.net.URL#openConnection()
* @see java.net.URLConnection#setUseCaches(boolean)
* @see java.net.URLConnection#getInputStream()
*/
public InputStream getInputStream() throws IOException {
URLConnection con = this.url.openConnection();
ResourceUtils.useCachesIfNecessary(con);
try {
return con.getInputStream();
} catch (IOException ex) {
// Close the HTTP connection (if applicable).
if (con instanceof HttpURLConnection) {
((HttpURLConnection) con).disconnect();
}
throw ex;
}
}
/**
* This implementation returns the underlying URL reference.
*/
@Override
public URL getURL(){
return this.url;
}
/**
* This implementation returns the underlying URI directly, if possible.
*/
@Override
public URI getURI() throws IOException {
if (this.uri != null) {
return this.uri;
} else {
return super.getURI();
}
}
/**
* This implementation returns a File reference for the underlying URL/URI,
* provided that it refers to a file in the file system.
*
* @see org.springframework.util.ResourceUtils#getFile(java.net.URL, String)
*/
@Override
public File getFile() throws IOException {
if (this.uri != null) {
return super.getFile(this.uri);
} else {
return super.getFile();
}
}
/**
* This implementation creates a UrlResource, applying the given path
* relative to the path of the underlying URL of this resource descriptor.
*
* @see java.net.URL#URL(java.net.URL, String)
*/
@Override
public IResource createRelative(String relativePath) throws MalformedURLException {
if (relativePath.startsWith("/")) {
relativePath = relativePath.substring(1);
}
return new UrlResource(new URL(this.url, relativePath));
}
/**
* This implementation returns the name of the file that this URL refers to.
*
* @see java.net.URL#getFile()
* @see java.io.File#getName()
*/
@Override
public String getFilename() {
return new File(this.url.getFile()).getName();
}
/**
* This implementation returns a description that includes the URL.
*/
public String getDescription() {
return "URL [" + this.url + "]";
}
/**
* This implementation compares the underlying URL references.
*/
@Override
public boolean equals(Object obj) {
return (obj == this || (obj instanceof UrlResource && this.cleanedUrl.equals(((UrlResource) obj).cleanedUrl)));
}
/**
* This implementation returns the hash code of the underlying URL
* reference.
*/
@Override
public int hashCode() {
return this.cleanedUrl.hashCode();
}
private static final String FOLDER_SEPARATOR = "/";
private static final String WINDOWS_FOLDER_SEPARATOR = "\\";
private static final String TOP_PATH = "..";
private static final String CURRENT_PATH = ".";
/**
* Path当中的路径进行精简和折叠。
* 其实这个功能一般无需自行编写，JDK中的{@link java.io.File#getCanonicalPath())就能起到相同作用。
* 此方法直接针对String进行处理，因此可以适用于各种非本地文件的URL的场合
*
* Normalize the path by suppressing sequences like "path/.." and
* inner simple dots.
* <p>The result is convenient for path comparison. For other uses,
* notice that Windows separators ("\") are replaced by simple slashes.
* @param path the original path
* @return the normalized path
*/
public static String cleanPath(String path) {
if (path == null) {
return null;
}
String pathToUse = StringUtils.replace(path, WINDOWS_FOLDER_SEPARATOR, FOLDER_SEPARATOR);
// Strip prefix from path to analyze, to not treat it as part of the
// first path element. This is necessary to correctly parse paths like
// "file:core/../core/io/Resource.class", where the ".." should just
// strip the first "core" directory while keeping the "file:" prefix.
int prefixIndex = pathToUse.indexOf(":");
String prefix = "";
if (prefixIndex != -1) {
prefix = pathToUse.substring(0, prefixIndex + 1);
pathToUse = pathToUse.substring(prefixIndex + 1);
}
if (pathToUse.startsWith(FOLDER_SEPARATOR)) {
prefix = prefix + FOLDER_SEPARATOR;
pathToUse = pathToUse.substring(1);
}
String[] pathArray = StringUtils.split(pathToUse, FOLDER_SEPARATOR);
List<String> pathElements = new LinkedList<String>();
int tops = 0;
for (int i = pathArray.length - 1; i >= 0; i--) {
String element = pathArray[i];
if (CURRENT_PATH.equals(element)) {
// Points to current directory - drop it.
}
else if (TOP_PATH.equals(element)) {
// Registering top path found.
tops++;
}
else {
if (tops > 0) {
// Merging path element with element corresponding to top path.
tops--;
}
else {
// Normal path element found.
pathElements.add(0, element);
}
}
}
// Remaining top paths need to be retained.
for (int i = 0; i < tops; i++) {
pathElements.add(0, TOP_PATH);
}
return prefix + StringUtils.join(pathElements, FOLDER_SEPARATOR);
}
@Override
public boolean isFile() {
String p=url.getProtocol();
return p.startsWith(ResourceUtils.URL_PROTOCOL_VFS)||"file".equals(p);
}
}