Java tutorial
/* * Copyright (c) 1995, 2019, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.net; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.net.spi.URLStreamHandlerProvider; import java.nio.file.Path; import java.security.AccessController; import java.security.PrivilegedAction; import java.util.Hashtable; import java.io.InvalidObjectException; import java.io.ObjectStreamException; import java.io.ObjectStreamField; import java.io.ObjectInputStream.GetField; import java.util.Iterator; import java.util.Locale; import java.util.NoSuchElementException; import java.util.ServiceConfigurationError; import java.util.ServiceLoader; import jdk.internal.access.JavaNetURLAccess; import jdk.internal.access.SharedSecrets; import sun.security.util.SecurityConstants; import sun.security.action.GetPropertyAction; /** * Class {@code URL} represents a Uniform Resource * Locator, a pointer to a "resource" on the World * Wide Web. A resource can be something as simple as a file or a * directory, or it can be a reference to a more complicated object, * such as a query to a database or to a search engine. More * information on the types of URLs and their formats can be found at: * <a href= * "http://web.archive.org/web/20051219043731/http://archive.ncsa.uiuc.edu/SDG/Software/Mosaic/Demo/url-primer.html"> * <i>Types of URL</i></a> * <p> * In general, a URL can be broken into several parts. Consider the * following example: * <blockquote><pre> * http://www.example.com/docs/resource1.html * </pre></blockquote> * <p> * The URL above indicates that the protocol to use is * {@code http} (HyperText Transfer Protocol) and that the * information resides on a host machine named * {@code www.example.com}. The information on that host * machine is named {@code /docs/resource1.html}. The exact * meaning of this name on the host machine is both protocol * dependent and host dependent. The information normally resides in * a file, but it could be generated on the fly. This component of * the URL is called the <i>path</i> component. * <p> * A URL can optionally specify a "port", which is the * port number to which the TCP connection is made on the remote host * machine. If the port is not specified, the default port for * the protocol is used instead. For example, the default port for * {@code http} is {@code 80}. An alternative port could be * specified as: * <blockquote><pre> * http://www.example.com:1080/docs/resource1.html * </pre></blockquote> * <p> * The syntax of {@code URL} is defined by <a * href="http://www.ietf.org/rfc/rfc2396.txt"><i>RFC 2396: Uniform * Resource Identifiers (URI): Generic Syntax</i></a>, amended by <a * href="http://www.ietf.org/rfc/rfc2732.txt"><i>RFC 2732: Format for * Literal IPv6 Addresses in URLs</i></a>. The Literal IPv6 address format * also supports scope_ids. The syntax and usage of scope_ids is described * <a href="Inet6Address.html#scoped">here</a>. * <p> * A URL may have appended to it a "fragment", also known * as a "ref" or a "reference". The fragment is indicated by the sharp * sign character "#" followed by more characters. For example, * <blockquote><pre> * http://www.example.com/index.html#chapter1 * </pre></blockquote> * <p> * This fragment is not technically part of the URL. Rather, it * indicates that after the specified resource is retrieved, the * application is specifically interested in that part of the * document that has the tag {@code chapter1} attached to it. The * meaning of a tag is resource specific. * <p> * An application can also specify a "relative URL", * which contains only enough information to reach the resource * relative to another URL. Relative URLs are frequently used within * HTML pages. For example, if the contents of the URL: * <blockquote><pre> * http://www.example.com/index.html * </pre></blockquote> * contained within it the relative URL: * <blockquote><pre> * FAQ.html * </pre></blockquote> * it would be a shorthand for: * <blockquote><pre> * http://www.example.com/FAQ.html * </pre></blockquote> * <p> * The relative URL need not specify all the components of a URL. If * the protocol, host name, or port number is missing, the value is * inherited from the fully specified URL. The file component must be * specified. The optional fragment is not inherited. * <p> * The URL class does not itself encode or decode any URL components * according to the escaping mechanism defined in RFC2396. It is the * responsibility of the caller to encode any fields, which need to be * escaped prior to calling URL, and also to decode any escaped fields, * that are returned from URL. Furthermore, because URL has no knowledge * of URL escaping, it does not recognise equivalence between the encoded * or decoded form of the same URL. For example, the two URLs:<br> * <pre> http://foo.com/hello world/ and http://foo.com/hello%20world</pre> * would be considered not equal to each other. * <p> * Note, the {@link java.net.URI} class does perform escaping of its * component fields in certain circumstances. The recommended way * to manage the encoding and decoding of URLs is to use {@link java.net.URI}, * and to convert between these two classes using {@link #toURI()} and * {@link URI#toURL()}. * <p> * The {@link URLEncoder} and {@link URLDecoder} classes can also be * used, but only for HTML form encoding, which is not the same * as the encoding scheme defined in RFC2396. * * @apiNote * * Applications working with file paths and file URIs should take great * care to use the appropriate methods to convert between the two. * The {@link Path#of(URI)} factory method and the {@link File#File(URI)} * constructor can be used to create {@link Path} or {@link File} * objects from a file URI. {@link Path#toUri()} and {@link File#toURI()} * can be used to create a {@link URI} from a file path, which can be * converted to URL using {@link URI#toURL()}. * Applications should never try to {@linkplain #URL(String, String, String) * construct} or {@linkplain #URL(String) parse} a {@code URL} * from the direct string representation of a {@code File} or {@code Path} * instance. * <p> * Some components of a URL or URI, such as <i>userinfo</i>, may * be abused to construct misleading URLs or URIs. Applications * that deal with URLs or URIs should take into account * the recommendations advised in <a * href="https://tools.ietf.org/html/rfc3986#section-7">RFC3986, * Section 7, Security Considerations</a>. * * @author James Gosling * @since 1.0 */ public final class URL implements java.io.Serializable { static final String BUILTIN_HANDLERS_PREFIX = "sun.net.www.protocol"; static final long serialVersionUID = -7627629688361524110L; /** * The property which specifies the package prefix list to be scanned * for protocol handlers. The value of this property (if any) should * be a vertical bar delimited list of package names to search through * for a protocol handler to load. The policy of this class is that * all protocol handlers will be in a class called <protocolname>.Handler, * and each package in the list is examined in turn for a matching * handler. If none are found (or the property is not specified), the * default package prefix, sun.net.www.protocol, is used. The search * proceeds from the first package in the list to the last and stops * when a match is found. */ private static final String protocolPathProp = "java.protocol.handler.pkgs"; /** * The protocol to use (ftp, http, nntp, ... etc.) . * @serial */ private String protocol; /** * The host name to connect to. * @serial */ private String host; /** * The protocol port to connect to. * @serial */ private int port = -1; /** * The specified file name on that host. {@code file} is * defined as {@code path[?query]} * @serial */ private String file; /** * The query part of this URL. */ private transient String query; /** * The authority part of this URL. * @serial */ private String authority; /** * The path part of this URL. */ private transient String path; /** * The userinfo part of this URL. */ private transient String userInfo; /** * # reference. * @serial */ private String ref; /** * The host's IP address, used in equals and hashCode. * Computed on demand. An uninitialized or unknown hostAddress is null. */ transient InetAddress hostAddress; /** * The URLStreamHandler for this URL. */ transient URLStreamHandler handler; /* Our hash code. * @serial */ private int hashCode = -1; private transient UrlDeserializedState tempState; /** * Creates a {@code URL} object from the specified * {@code protocol}, {@code host}, {@code port} * number, and {@code file}.<p> * * {@code host} can be expressed as a host name or a literal * IP address. If IPv6 literal address is used, it should be * enclosed in square brackets ({@code '['} and {@code ']'}), as * specified by <a * href="http://www.ietf.org/rfc/rfc2732.txt">RFC 2732</a>; * However, the literal IPv6 address format defined in <a * href="http://www.ietf.org/rfc/rfc2373.txt"><i>RFC 2373: IP * Version 6 Addressing Architecture</i></a> is also accepted.<p> * * Specifying a {@code port} number of {@code -1} * indicates that the URL should use the default port for the * protocol.<p> * * If this is the first URL object being created with the specified * protocol, a <i>stream protocol handler</i> object, an instance of * class {@code URLStreamHandler}, is created for that protocol: * <ol> * <li>If the application has previously set up an instance of * {@code URLStreamHandlerFactory} as the stream handler factory, * then the {@code createURLStreamHandler} method of that instance * is called with the protocol string as an argument to create the * stream protocol handler. * <li>If no {@code URLStreamHandlerFactory} has yet been set up, * or if the factory's {@code createURLStreamHandler} method * returns {@code null}, then the {@linkplain java.util.ServiceLoader * ServiceLoader} mechanism is used to locate {@linkplain * java.net.spi.URLStreamHandlerProvider URLStreamHandlerProvider} * implementations using the system class * loader. The order that providers are located is implementation * specific, and an implementation is free to cache the located * providers. A {@linkplain java.util.ServiceConfigurationError * ServiceConfigurationError}, {@code Error} or {@code RuntimeException} * thrown from the {@code createURLStreamHandler}, if encountered, will * be propagated to the calling thread. The {@code * createURLStreamHandler} method of each provider, if instantiated, is * invoked, with the protocol string, until a provider returns non-null, * or all providers have been exhausted. * <li>If the previous step fails to find a protocol handler, the * constructor reads the value of the system property: * <blockquote>{@systemProperty * java.protocol.handler.pkgs * }</blockquote> * If the value of that system property is not {@code null}, * it is interpreted as a list of packages separated by a vertical * slash character '{@code |}'. The constructor tries to load * the class named: * <blockquote>{@code * <package>.<protocol>.Handler * }</blockquote> * where {@code <package>} is replaced by the name of the package * and {@code <protocol>} is replaced by the name of the protocol. * If this class does not exist, or if the class exists but it is not * a subclass of {@code URLStreamHandler}, then the next package * in the list is tried. * <li>If the previous step fails to find a protocol handler, then the * constructor tries to load a built-in protocol handler. * If this class does not exist, or if the class exists but it is not a * subclass of {@code URLStreamHandler}, then a * {@code MalformedURLException} is thrown. * </ol> * * <p>Protocol handlers for the following protocols are guaranteed * to exist on the search path :- * <blockquote><pre> * http, https, file, and jar * </pre></blockquote> * Protocol handlers for additional protocols may also be available. * Some protocol handlers, for example those used for loading platform * classes or classes on the class path, may not be overridden. The details * of such restrictions, and when those restrictions apply (during * initialization of the runtime for example), are implementation specific * and therefore not specified * * <p>No validation of the inputs is performed by this constructor. * * @param protocol the name of the protocol to use. * @param host the name of the host. * @param port the port number on the host. * @param file the file on the host * @exception MalformedURLException if an unknown protocol or the port * is a negative number other than -1 * @see java.lang.System#getProperty(java.lang.String) * @see java.net.URL#setURLStreamHandlerFactory( * java.net.URLStreamHandlerFactory) * @see java.net.URLStreamHandler * @see java.net.URLStreamHandlerFactory#createURLStreamHandler( * java.lang.String) */ public URL(String protocol, String host, int port, String file) throws MalformedURLException { this(protocol, host, port, file, null); } /** * Creates a URL from the specified {@code protocol} * name, {@code host} name, and {@code file} name. The * default port for the specified protocol is used. * <p> * This constructor is equivalent to the four-argument * constructor with the only difference of using the * default port for the specified protocol. * * No validation of the inputs is performed by this constructor. * * @param protocol the name of the protocol to use. * @param host the name of the host. * @param file the file on the host. * @exception MalformedURLException if an unknown protocol is specified. * @see java.net.URL#URL(java.lang.String, java.lang.String, * int, java.lang.String) */ public URL(String protocol, String host, String file) throws MalformedURLException { this(protocol, host, -1, file); } /** * Creates a {@code URL} object from the specified * {@code protocol}, {@code host}, {@code port} * number, {@code file}, and {@code handler}. Specifying * a {@code port} number of {@code -1} indicates that * the URL should use the default port for the protocol. Specifying * a {@code handler} of {@code null} indicates that the URL * should use a default stream handler for the protocol, as outlined * for: * java.net.URL#URL(java.lang.String, java.lang.String, int, * java.lang.String) * * <p>If the handler is not null and there is a security manager, * the security manager's {@code checkPermission} * method is called with a * {@code NetPermission("specifyStreamHandler")} permission. * This may result in a SecurityException. * * No validation of the inputs is performed by this constructor. * * @param protocol the name of the protocol to use. * @param host the name of the host. * @param port the port number on the host. * @param file the file on the host * @param handler the stream handler for the URL. * @exception MalformedURLException if an unknown protocol or the port is a negative number other than -1 * @exception SecurityException * if a security manager exists and its * {@code checkPermission} method doesn't allow * specifying a stream handler explicitly. * @see java.lang.System#getProperty(java.lang.String) * @see java.net.URL#setURLStreamHandlerFactory( * java.net.URLStreamHandlerFactory) * @see java.net.URLStreamHandler * @see java.net.URLStreamHandlerFactory#createURLStreamHandler( * java.lang.String) * @see SecurityManager#checkPermission * @see java.net.NetPermission */ public URL(String protocol, String host, int port, String file, URLStreamHandler handler) throws MalformedURLException { if (handler != null) { SecurityManager sm = System.getSecurityManager(); if (sm != null) { // check for permission to specify a handler checkSpecifyHandler(sm); } } protocol = toLowerCase(protocol); this.protocol = protocol; if (host != null) { /** * if host is a literal IPv6 address, * we will make it conform to RFC 2732 */ if (host.indexOf(':') >= 0 && !host.startsWith("[")) { host = "[" + host + "]"; } this.host = host; if (port < -1) { throw new MalformedURLException("Invalid port number :" + port); } this.port = port; authority = (port == -1) ? host : host + ":" + port; } int index = file.indexOf('#'); this.ref = index < 0 ? null : file.substring(index + 1); file = index < 0 ? file : file.substring(0, index); int q = file.lastIndexOf('?'); if (q != -1) { this.query = file.substring(q + 1); this.path = file.substring(0, q); this.file = path + "?" + query; } else { this.path = file; this.file = path; } // Note: we don't do validation of the URL here. Too risky to change // right now, but worth considering for future reference. -br if (handler == null && (handler = getURLStreamHandler(protocol)) == null) { throw new MalformedURLException("unknown protocol: " + protocol); } this.handler = handler; } /** * Creates a {@code URL} object from the {@code String} * representation. * <p> * This constructor is equivalent to a call to the two-argument * constructor with a {@code null} first argument. * * @param spec the {@code String} to parse as a URL. * @exception MalformedURLException if no protocol is specified, or an * unknown protocol is found, or {@code spec} is {@code null}, * or the parsed URL fails to comply with the specific syntax * of the associated protocol. * @see java.net.URL#URL(java.net.URL, java.lang.String) */ public URL(String spec) throws MalformedURLException { this(null, spec); } /** * Creates a URL by parsing the given spec within a specified context. * * The new URL is created from the given context URL and the spec * argument as described in * RFC2396 "Uniform Resource Identifiers : Generic * Syntax" : * <blockquote><pre> * <scheme>://<authority><path>?<query>#<fragment> * </pre></blockquote> * The reference is parsed into the scheme, authority, path, query and * fragment parts. If the path component is empty and the scheme, * authority, and query components are undefined, then the new URL is a * reference to the current document. Otherwise, the fragment and query * parts present in the spec are used in the new URL. * <p> * If the scheme component is defined in the given spec and does not match * the scheme of the context, then the new URL is created as an absolute * URL based on the spec alone. Otherwise the scheme component is inherited * from the context URL. * <p> * If the authority component is present in the spec then the spec is * treated as absolute and the spec authority and path will replace the * context authority and path. If the authority component is absent in the * spec then the authority of the new URL will be inherited from the * context. * <p> * If the spec's path component begins with a slash character * "/" then the * path is treated as absolute and the spec path replaces the context path. * <p> * Otherwise, the path is treated as a relative path and is appended to the * context path, as described in RFC2396. Also, in this case, * the path is canonicalized through the removal of directory * changes made by occurrences of ".." and ".". * <p> * For a more detailed description of URL parsing, refer to RFC2396. * * @param context the context in which to parse the specification. * @param spec the {@code String} to parse as a URL. * @exception MalformedURLException if no protocol is specified, or an * unknown protocol is found, or {@code spec} is {@code null}, * or the parsed URL fails to comply with the specific syntax * of the associated protocol. * @see java.net.URL#URL(java.lang.String, java.lang.String, * int, java.lang.String) * @see java.net.URLStreamHandler * @see java.net.URLStreamHandler#parseURL(java.net.URL, * java.lang.String, int, int) */ public URL(URL context, String spec) throws MalformedURLException { this(context, spec, null); } /** * Creates a URL by parsing the given spec with the specified handler * within a specified context. If the handler is null, the parsing * occurs as with the two argument constructor. * * @param context the context in which to parse the specification. * @param spec the {@code String} to parse as a URL. * @param handler the stream handler for the URL. * @exception MalformedURLException if no protocol is specified, or an * unknown protocol is found, or {@code spec} is {@code null}, * or the parsed URL fails to comply with the specific syntax * of the associated protocol. * @exception SecurityException * if a security manager exists and its * {@code checkPermission} method doesn't allow * specifying a stream handler. * @see java.net.URL#URL(java.lang.String, java.lang.String, * int, java.lang.String) * @see java.net.URLStreamHandler * @see java.net.URLStreamHandler#parseURL(java.net.URL, * java.lang.String, int, int) */ public URL(URL context, String spec, URLStreamHandler handler) throws MalformedURLException { String original = spec; int i, limit, c; int start = 0; String newProtocol = null; boolean aRef = false; boolean isRelative = false; // Check for permission to specify a handler if (handler != null) { SecurityManager sm = System.getSecurityManager(); if (sm != null) { checkSpecifyHandler(sm); } } try { limit = spec.length(); while ((limit > 0) && (spec.charAt(limit - 1) <= ' ')) { limit--; //eliminate trailing whitespace } while ((start < limit) && (spec.charAt(start) <= ' ')) { start++; // eliminate leading whitespace } if (spec.regionMatches(true, start, "url:", 0, 4)) { start += 4; } if (start < spec.length() && spec.charAt(start) == '#') { /* we're assuming this is a ref relative to the context URL. * This means protocols cannot start w/ '#', but we must parse * ref URL's like: "hello:there" w/ a ':' in them. */ aRef = true; } for (i = start; !aRef && (i < limit) && ((c = spec.charAt(i)) != '/'); i++) { if (c == ':') { String s = toLowerCase(spec.substring(start, i)); if (isValidProtocol(s)) { newProtocol = s; start = i + 1; } break; } } // Only use our context if the protocols match. protocol = newProtocol; if ((context != null) && ((newProtocol == null) || newProtocol.equalsIgnoreCase(context.protocol))) { // inherit the protocol handler from the context // if not specified to the constructor if (handler == null) { handler = context.handler; } // If the context is a hierarchical URL scheme and the spec // contains a matching scheme then maintain backwards // compatibility and treat it as if the spec didn't contain // the scheme; see 5.2.3 of RFC2396 if (context.path != null && context.path.startsWith("/")) newProtocol = null; if (newProtocol == null) { protocol = context.protocol; authority = context.authority; userInfo = context.userInfo; host = context.host; port = context.port; file = context.file; path = context.path; isRelative = true; } } if (protocol == null) { throw new MalformedURLException("no protocol: " + original); } // Get the protocol handler if not specified or the protocol // of the context could not be used if (handler == null && (handler = getURLStreamHandler(protocol)) == null) { throw new MalformedURLException("unknown protocol: " + protocol); } this.handler = handler; i = spec.indexOf('#', start); if (i >= 0) { ref = spec.substring(i + 1, limit); limit = i; } /* * Handle special case inheritance of query and fragment * implied by RFC2396 section 5.2.2. */ if (isRelative && start == limit) { query = context.query; if (ref == null) { ref = context.ref; } } handler.parseURL(this, spec, start, limit); } catch (MalformedURLException e) { throw e; } catch (Exception e) { MalformedURLException exception = new MalformedURLException(e.getMessage()); exception.initCause(e); throw exception; } } /** * Creates a URL from a URI, as if by invoking {@code uri.toURL()}. * * @see java.net.URI#toURL() */ static URL fromURI(URI uri) throws MalformedURLException { if (!uri.isAbsolute()) { throw new IllegalArgumentException("URI is not absolute"); } String protocol = uri.getScheme(); // In general we need to go via Handler.parseURL, but for the jrt // protocol we enforce that the Handler is not overrideable and can // optimize URI to URL conversion. // // Case-sensitive comparison for performance; malformed protocols will // be handled correctly by the slow path. if (protocol.equals("jrt") && !uri.isOpaque() && uri.getRawFragment() == null) { String query = uri.getRawQuery(); String path = uri.getRawPath(); String file = (query == null) ? path : path + "?" + query; // URL represent undefined host as empty string while URI use null String host = uri.getHost(); if (host == null) { host = ""; } int port = uri.getPort(); return new URL("jrt", host, port, file, null); } else { return new URL((URL) null, uri.toString(), null); } } /* * Returns true if specified string is a valid protocol name. */ private boolean isValidProtocol(String protocol) { int len = protocol.length(); if (len < 1) return false; char c = protocol.charAt(0); if (!Character.isLetter(c)) return false; for (int i = 1; i < len; i++) { c = protocol.charAt(i); if (!Character.isLetterOrDigit(c) && c != '.' && c != '+' && c != '-') { return false; } } return true; } /* * Checks for permission to specify a stream handler. */ private void checkSpecifyHandler(SecurityManager sm) { sm.checkPermission(SecurityConstants.SPECIFY_HANDLER_PERMISSION); } /** * Sets the fields of the URL. This is not a public method so that * only URLStreamHandlers can modify URL fields. URLs are * otherwise constant. * * @param protocol the name of the protocol to use * @param host the name of the host @param port the port number on the host * @param file the file on the host * @param ref the internal reference in the URL */ void set(String protocol, String host, int port, String file, String ref) { synchronized (this) { this.protocol = protocol; this.host = host; authority = port == -1 ? host : host + ":" + port; this.port = port; this.file = file; this.ref = ref; /* This is very important. We must recompute this after the * URL has been changed. */ hashCode = -1; hostAddress = null; int q = file.lastIndexOf('?'); if (q != -1) { query = file.substring(q + 1); path = file.substring(0, q); } else path = file; } } /** * Sets the specified 8 fields of the URL. This is not a public method so * that only URLStreamHandlers can modify URL fields. URLs are otherwise * constant. * * @param protocol the name of the protocol to use * @param host the name of the host * @param port the port number on the host * @param authority the authority part for the url * @param userInfo the username and password * @param path the file on the host * @param ref the internal reference in the URL * @param query the query part of this URL * @since 1.3 */ void set(String protocol, String host, int port, String authority, String userInfo, String path, String query, String ref) { synchronized (this) { this.protocol = protocol; this.host = host; this.port = port; this.file = query == null ? path : path + "?" + query; this.userInfo = userInfo; this.path = path; this.ref = ref; /* This is very important. We must recompute this after the * URL has been changed. */ hashCode = -1; hostAddress = null; this.query = query; this.authority = authority; } } /** * Gets the query part of this {@code URL}. * * @return the query part of this {@code URL}, * or <CODE>null</CODE> if one does not exist * @since 1.3 */ public String getQuery() { return query; } /** * Gets the path part of this {@code URL}. * * @return the path part of this {@code URL}, or an * empty string if one does not exist * @since 1.3 */ public String getPath() { return path; } /** * Gets the userInfo part of this {@code URL}. * * @return the userInfo part of this {@code URL}, or * <CODE>null</CODE> if one does not exist * @since 1.3 */ public String getUserInfo() { return userInfo; } /** * Gets the authority part of this {@code URL}. * * @return the authority part of this {@code URL} * @since 1.3 */ public String getAuthority() { return authority; } /** * Gets the port number of this {@code URL}. * * @return the port number, or -1 if the port is not set */ public int getPort() { return port; } /** * Gets the default port number of the protocol associated * with this {@code URL}. If the URL scheme or the URLStreamHandler * for the URL do not define a default port number, * then -1 is returned. * * @return the port number * @since 1.4 */ public int getDefaultPort() { return handler.getDefaultPort(); } /** * Gets the protocol name of this {@code URL}. * * @return the protocol of this {@code URL}. */ public String getProtocol() { return protocol; } /** * Gets the host name of this {@code URL}, if applicable. * The format of the host conforms to RFC 2732, i.e. for a * literal IPv6 address, this method will return the IPv6 address * enclosed in square brackets ({@code '['} and {@code ']'}). * * @return the host name of this {@code URL}. */ public String getHost() { return host; } /** * Gets the file name of this {@code URL}. * The returned file portion will be * the same as <CODE>getPath()</CODE>, plus the concatenation of * the value of <CODE>getQuery()</CODE>, if any. If there is * no query portion, this method and <CODE>getPath()</CODE> will * return identical results. * * @return the file name of this {@code URL}, * or an empty string if one does not exist */ public String getFile() { return file; } /** * Gets the anchor (also known as the "reference") of this * {@code URL}. * * @return the anchor (also known as the "reference") of this * {@code URL}, or <CODE>null</CODE> if one does not exist */ public String getRef() { return ref; } /** * Compares this URL for equality with another object.<p> * * If the given object is not a URL then this method immediately returns * {@code false}.<p> * * Two URL objects are equal if they have the same protocol, reference * equivalent hosts, have the same port number on the host, and the same * file and fragment of the file.<p> * * Two hosts are considered equivalent if both host names can be resolved * into the same IP addresses; else if either host name can't be * resolved, the host names must be equal without regard to case; or both * host names equal to null.<p> * * Since hosts comparison requires name resolution, this operation is a * blocking operation. <p> * * Note: The defined behavior for {@code equals} is known to * be inconsistent with virtual hosting in HTTP. * * @param obj the URL to compare against. * @return {@code true} if the objects are the same; * {@code false} otherwise. */ public boolean equals(Object obj) { if (!(obj instanceof URL)) return false; URL u2 = (URL) obj; return handler.equals(this, u2); } /** * Creates an integer suitable for hash table indexing.<p> * * The hash code is based upon all the URL components relevant for URL * comparison. As such, this operation is a blocking operation. * * @return a hash code for this {@code URL}. */ public synchronized int hashCode() { if (hashCode != -1) return hashCode; hashCode = handler.hashCode(this); return hashCode; } /** * Compares two URLs, excluding the fragment component.<p> * * Returns {@code true} if this {@code URL} and the * {@code other} argument are equal without taking the * fragment component into consideration. * * @param other the {@code URL} to compare against. * @return {@code true} if they reference the same remote object; * {@code false} otherwise. */ public boolean sameFile(URL other) { return handler.sameFile(this, other); } /** * Constructs a string representation of this {@code URL}. The * string is created by calling the {@code toExternalForm} * method of the stream protocol handler for this object. * * @return a string representation of this object. * @see java.net.URL#URL(java.lang.String, java.lang.String, int, * java.lang.String) * @see java.net.URLStreamHandler#toExternalForm(java.net.URL) */ public String toString() { return toExternalForm(); } /** * Constructs a string representation of this {@code URL}. The * string is created by calling the {@code toExternalForm} * method of the stream protocol handler for this object. * * @return a string representation of this object. * @see java.net.URL#URL(java.lang.String, java.lang.String, * int, java.lang.String) * @see java.net.URLStreamHandler#toExternalForm(java.net.URL) */ public String toExternalForm() { return handler.toExternalForm(this); } /** * Returns a {@link java.net.URI} equivalent to this URL. * This method functions in the same way as {@code new URI (this.toString())}. * <p>Note, any URL instance that complies with RFC 2396 can be converted * to a URI. However, some URLs that are not strictly in compliance * can not be converted to a URI. * * @exception URISyntaxException if this URL is not formatted strictly according to * RFC2396 and cannot be converted to a URI. * * @return a URI instance equivalent to this URL. * @since 1.5 */ public URI toURI() throws URISyntaxException { return new URI(toString()); } /** * Returns a {@link java.net.URLConnection URLConnection} instance that * represents a connection to the remote object referred to by the * {@code URL}. * * <P>A new instance of {@linkplain java.net.URLConnection URLConnection} is * created every time when invoking the * {@linkplain java.net.URLStreamHandler#openConnection(URL) * URLStreamHandler.openConnection(URL)} method of the protocol handler for * this URL.</P> * * <P>It should be noted that a URLConnection instance does not establish * the actual network connection on creation. This will happen only when * calling {@linkplain java.net.URLConnection#connect() URLConnection.connect()}.</P> * * <P>If for the URL's protocol (such as HTTP or JAR), there * exists a public, specialized URLConnection subclass belonging * to one of the following packages or one of their subpackages: * java.lang, java.io, java.util, java.net, the connection * returned will be of that subclass. For example, for HTTP an * HttpURLConnection will be returned, and for JAR a * JarURLConnection will be returned.</P> * * @return a {@link java.net.URLConnection URLConnection} linking * to the URL. * @exception IOException if an I/O exception occurs. * @see java.net.URL#URL(java.lang.String, java.lang.String, * int, java.lang.String) */ public URLConnection openConnection() throws java.io.IOException { return handler.openConnection(this); } /** * Same as {@link #openConnection()}, except that the connection will be * made through the specified proxy; Protocol handlers that do not * support proxying will ignore the proxy parameter and make a * normal connection. * * Invoking this method preempts the system's default * {@link java.net.ProxySelector ProxySelector} settings. * * @param proxy the Proxy through which this connection * will be made. If direct connection is desired, * Proxy.NO_PROXY should be specified. * @return a {@code URLConnection} to the URL. * @exception IOException if an I/O exception occurs. * @exception SecurityException if a security manager is present * and the caller doesn't have permission to connect * to the proxy. * @exception IllegalArgumentException will be thrown if proxy is null, * or proxy has the wrong type * @exception UnsupportedOperationException if the subclass that * implements the protocol handler doesn't support * this method. * @see java.net.URL#URL(java.lang.String, java.lang.String, * int, java.lang.String) * @see java.net.URLConnection * @see java.net.URLStreamHandler#openConnection(java.net.URL, * java.net.Proxy) * @since 1.5 */ public URLConnection openConnection(Proxy proxy) throws java.io.IOException { if (proxy == null) { throw new IllegalArgumentException("proxy can not be null"); } // Create a copy of Proxy as a security measure Proxy p = proxy == Proxy.NO_PROXY ? Proxy.NO_PROXY : sun.net.ApplicationProxy.create(proxy); SecurityManager sm = System.getSecurityManager(); if (p.type() != Proxy.Type.DIRECT && sm != null) { InetSocketAddress epoint = (InetSocketAddress) p.address(); if (epoint.isUnresolved()) sm.checkConnect(epoint.getHostName(), epoint.getPort()); else sm.checkConnect(epoint.getAddress().getHostAddress(), epoint.getPort()); } return handler.openConnection(this, p); } /** * Opens a connection to this {@code URL} and returns an * {@code InputStream} for reading from that connection. This * method is a shorthand for: * <blockquote><pre> * openConnection().getInputStream() * </pre></blockquote> * * @return an input stream for reading from the URL connection. * @exception IOException if an I/O exception occurs. * @see java.net.URL#openConnection() * @see java.net.URLConnection#getInputStream() */ public final InputStream openStream() throws java.io.IOException { return openConnection().getInputStream(); } /** * Gets the contents of this URL. This method is a shorthand for: * <blockquote><pre> * openConnection().getContent() * </pre></blockquote> * * @return the contents of this URL. * @exception IOException if an I/O exception occurs. * @see java.net.URLConnection#getContent() */ public final Object getContent() throws java.io.IOException { return openConnection().getContent(); } /** * Gets the contents of this URL. This method is a shorthand for: * <blockquote><pre> * openConnection().getContent(classes) * </pre></blockquote> * * @param classes an array of Java types * @return the content object of this URL that is the first match of * the types specified in the classes array. * null if none of the requested types are supported. * @exception IOException if an I/O exception occurs. * @see java.net.URLConnection#getContent(Class[]) * @since 1.3 */ public final Object getContent(Class<?>[] classes) throws java.io.IOException { return openConnection().getContent(classes); } /** * The URLStreamHandler factory. */ private static volatile URLStreamHandlerFactory factory; /** * Sets an application's {@code URLStreamHandlerFactory}. * This method can be called at most once in a given Java Virtual * Machine. * *<p> The {@code URLStreamHandlerFactory} instance is used to *construct a stream protocol handler from a protocol name. * * <p> If there is a security manager, this method first calls * the security manager's {@code checkSetFactory} method * to ensure the operation is allowed. * This could result in a SecurityException. * * @param fac the desired factory. * @exception Error if the application has already set a factory. * @exception SecurityException if a security manager exists and its * {@code checkSetFactory} method doesn't allow * the operation. * @see java.net.URL#URL(java.lang.String, java.lang.String, * int, java.lang.String) * @see java.net.URLStreamHandlerFactory * @see SecurityManager#checkSetFactory */ public static void setURLStreamHandlerFactory(URLStreamHandlerFactory fac) { synchronized (streamHandlerLock) { if (factory != null) { throw new Error("factory already defined"); } SecurityManager security = System.getSecurityManager(); if (security != null) { security.checkSetFactory(); } handlers.clear(); // safe publication of URLStreamHandlerFactory with volatile write factory = fac; } } private static final URLStreamHandlerFactory defaultFactory = new DefaultFactory(); private static class DefaultFactory implements URLStreamHandlerFactory { private static String PREFIX = "sun.net.www.protocol."; public URLStreamHandler createURLStreamHandler(String protocol) { // Avoid using reflection during bootstrap switch (protocol) { case "file": return new sun.net.www.protocol.file.Handler(); case "jar": return new sun.net.www.protocol.jar.Handler(); case "jrt": return new sun.net.www.protocol.jrt.Handler(); } String name = PREFIX + protocol + ".Handler"; try { Object o = Class.forName(name).getDeclaredConstructor().newInstance(); return (URLStreamHandler) o; } catch (Exception e) { // For compatibility, all Exceptions are ignored. // any number of exceptions can get thrown here } return null; } } private static URLStreamHandler lookupViaProperty(String protocol) { String packagePrefixList = GetPropertyAction.privilegedGetProperty(protocolPathProp); if (packagePrefixList == null) { // not set return null; } String[] packagePrefixes = packagePrefixList.split("\\|"); URLStreamHandler handler = null; for (int i = 0; handler == null && i < packagePrefixes.length; i++) { String packagePrefix = packagePrefixes[i].trim(); try { String clsName = packagePrefix + "." + protocol + ".Handler"; Class<?> cls = null; try { cls = Class.forName(clsName); } catch (ClassNotFoundException e) { ClassLoader cl = ClassLoader.getSystemClassLoader(); if (cl != null) { cls = cl.loadClass(clsName); } } if (cls != null) { @SuppressWarnings("deprecation") Object tmp = cls.newInstance(); handler = (URLStreamHandler) tmp; } } catch (Exception e) { // any number of exceptions can get thrown here } } return handler; } private static Iterator<URLStreamHandlerProvider> providers() { return new Iterator<>() { ClassLoader cl = ClassLoader.getSystemClassLoader(); ServiceLoader<URLStreamHandlerProvider> sl = ServiceLoader.load(URLStreamHandlerProvider.class, cl); Iterator<URLStreamHandlerProvider> i = sl.iterator(); URLStreamHandlerProvider next = null; private boolean getNext() { while (next == null) { try { if (!i.hasNext()) return false; next = i.next(); } catch (ServiceConfigurationError sce) { if (sce.getCause() instanceof SecurityException) { // Ignore security exceptions continue; } throw sce; } } return true; } public boolean hasNext() { return getNext(); } public URLStreamHandlerProvider next() { if (!getNext()) throw new NoSuchElementException(); URLStreamHandlerProvider n = next; next = null; return n; } }; } // Thread-local gate to prevent recursive provider lookups private static ThreadLocal<Object> gate = new ThreadLocal<>(); private static URLStreamHandler lookupViaProviders(final String protocol) { if (gate.get() != null) throw new Error("Circular loading of URL stream handler providers detected"); gate.set(gate); try { return AccessController.doPrivileged(new PrivilegedAction<>() { public URLStreamHandler run() { Iterator<URLStreamHandlerProvider> itr = providers(); while (itr.hasNext()) { URLStreamHandlerProvider f = itr.next(); URLStreamHandler h = f.createURLStreamHandler(protocol); if (h != null) return h; } return null; } }); } finally { gate.set(null); } } /** * Returns the protocol in lower case. Special cases known protocols * to avoid loading locale classes during startup. */ static String toLowerCase(String protocol) { if (protocol.equals("jrt") || protocol.equals("file") || protocol.equals("jar")) { return protocol; } else { return protocol.toLowerCase(Locale.ROOT); } } /** * Non-overrideable protocols: "jrt" and "file" * * Character-based comparison for performance reasons; also ensures * case-insensitive comparison in a locale-independent fashion. */ static boolean isOverrideable(String protocol) { if (protocol.length() == 3) { if ((Character.toLowerCase(protocol.charAt(0)) == 'j') && (Character.toLowerCase(protocol.charAt(1)) == 'r') && (Character.toLowerCase(protocol.charAt(2)) == 't')) { return false; } } else if (protocol.length() == 4) { if ((Character.toLowerCase(protocol.charAt(0)) == 'f') && (Character.toLowerCase(protocol.charAt(1)) == 'i') && (Character.toLowerCase(protocol.charAt(2)) == 'l') && (Character.toLowerCase(protocol.charAt(3)) == 'e')) { return false; } } return true; } /** * A table of protocol handlers. */ static Hashtable<String, URLStreamHandler> handlers = new Hashtable<>(); private static final Object streamHandlerLock = new Object(); /** * Returns the Stream Handler. * @param protocol the protocol to use */ static URLStreamHandler getURLStreamHandler(String protocol) { URLStreamHandler handler = handlers.get(protocol); if (handler != null) { return handler; } URLStreamHandlerFactory fac; boolean checkedWithFactory = false; boolean overrideableProtocol = isOverrideable(protocol); if (overrideableProtocol && jdk.internal.misc.VM.isBooted()) { // Use the factory (if any). Volatile read makes // URLStreamHandlerFactory appear fully initialized to current thread. fac = factory; if (fac != null) { handler = fac.createURLStreamHandler(protocol); checkedWithFactory = true; } if (handler == null && !protocol.equalsIgnoreCase("jar")) { handler = lookupViaProviders(protocol); } if (handler == null) { handler = lookupViaProperty(protocol); } } if (handler == null) { // Try the built-in protocol handler handler = defaultFactory.createURLStreamHandler(protocol); } synchronized (streamHandlerLock) { URLStreamHandler handler2 = null; // Check again with hashtable just in case another // thread created a handler since we last checked handler2 = handlers.get(protocol); if (handler2 != null) { return handler2; } // Check with factory if another thread set a // factory since our last check if (overrideableProtocol && !checkedWithFactory && (fac = factory) != null) { handler2 = fac.createURLStreamHandler(protocol); } if (handler2 != null) { // The handler from the factory must be given more // importance. Discard the default handler that // this thread created. handler = handler2; } // Insert this handler into the hashtable if (handler != null) { handlers.put(protocol, handler); } } return handler; } /** * @serialField protocol String * * @serialField host String * * @serialField port int * * @serialField authority String * * @serialField file String * * @serialField ref String * * @serialField hashCode int * */ private static final ObjectStreamField[] serialPersistentFields = { new ObjectStreamField("protocol", String.class), new ObjectStreamField("host", String.class), new ObjectStreamField("port", int.class), new ObjectStreamField("authority", String.class), new ObjectStreamField("file", String.class), new ObjectStreamField("ref", String.class), new ObjectStreamField("hashCode", int.class), }; /** * WriteObject is called to save the state of the URL to an * ObjectOutputStream. The handler is not saved since it is * specific to this system. * * @serialData the default write object value. When read back in, * the reader must ensure that calling getURLStreamHandler with * the protocol variable returns a valid URLStreamHandler and * throw an IOException if it does not. */ private synchronized void writeObject(java.io.ObjectOutputStream s) throws IOException { s.defaultWriteObject(); // write the fields } /** * readObject is called to restore the state of the URL from the * stream. It reads the components of the URL and finds the local * stream handler. */ private synchronized void readObject(java.io.ObjectInputStream s) throws IOException, ClassNotFoundException { GetField gf = s.readFields(); String protocol = (String) gf.get("protocol", null); if (getURLStreamHandler(protocol) == null) { throw new IOException("unknown protocol: " + protocol); } String host = (String) gf.get("host", null); int port = gf.get("port", -1); String authority = (String) gf.get("authority", null); String file = (String) gf.get("file", null); String ref = (String) gf.get("ref", null); int hashCode = gf.get("hashCode", -1); if (authority == null && ((host != null && !host.isEmpty()) || port != -1)) { if (host == null) host = ""; authority = (port == -1) ? host : host + ":" + port; } tempState = new UrlDeserializedState(protocol, host, port, authority, file, ref, hashCode); } /** * Replaces the de-serialized object with an URL object. * * @return a newly created object from deserialized data * * @throws ObjectStreamException if a new object replacing this * object could not be created */ private Object readResolve() throws ObjectStreamException { URLStreamHandler handler = null; // already been checked in readObject handler = getURLStreamHandler(tempState.getProtocol()); URL replacementURL = null; if (isBuiltinStreamHandler(handler.getClass().getName())) { replacementURL = fabricateNewURL(); } else { replacementURL = setDeserializedFields(handler); } return replacementURL; } private URL setDeserializedFields(URLStreamHandler handler) { URL replacementURL; String userInfo = null; String protocol = tempState.getProtocol(); String host = tempState.getHost(); int port = tempState.getPort(); String authority = tempState.getAuthority(); String file = tempState.getFile(); String ref = tempState.getRef(); int hashCode = tempState.getHashCode(); // Construct authority part if (authority == null && ((host != null && !host.isEmpty()) || port != -1)) { if (host == null) host = ""; authority = (port == -1) ? host : host + ":" + port; // Handle hosts with userInfo in them int at = host.lastIndexOf('@'); if (at != -1) { userInfo = host.substring(0, at); host = host.substring(at + 1); } } else if (authority != null) { // Construct user info part int ind = authority.indexOf('@'); if (ind != -1) userInfo = authority.substring(0, ind); } // Construct path and query part String path = null; String query = null; if (file != null) { // Fix: only do this if hierarchical? int q = file.lastIndexOf('?'); if (q != -1) { query = file.substring(q + 1); path = file.substring(0, q); } else path = file; } // Set the object fields. this.protocol = protocol; this.host = host; this.port = port; this.file = file; this.authority = authority; this.ref = ref; this.hashCode = hashCode; this.handler = handler; this.query = query; this.path = path; this.userInfo = userInfo; replacementURL = this; return replacementURL; } private URL fabricateNewURL() throws InvalidObjectException { // create URL string from deserialized object URL replacementURL = null; String urlString = tempState.reconstituteUrlString(); try { replacementURL = new URL(urlString); } catch (MalformedURLException mEx) { resetState(); InvalidObjectException invoEx = new InvalidObjectException("Malformed URL: " + urlString); invoEx.initCause(mEx); throw invoEx; } replacementURL.setSerializedHashCode(tempState.getHashCode()); resetState(); return replacementURL; } private boolean isBuiltinStreamHandler(String handlerClassName) { return (handlerClassName.startsWith(BUILTIN_HANDLERS_PREFIX)); } private void resetState() { this.protocol = null; this.host = null; this.port = -1; this.file = null; this.authority = null; this.ref = null; this.hashCode = -1; this.handler = null; this.query = null; this.path = null; this.userInfo = null; this.tempState = null; } private void setSerializedHashCode(int hc) { this.hashCode = hc; } static { SharedSecrets.setJavaNetURLAccess(new JavaNetURLAccess() { @Override public URLStreamHandler getHandler(URL u) { return u.handler; } }); } } final class UrlDeserializedState { private final String protocol; private final String host; private final int port; private final String authority; private final String file; private final String ref; private final int hashCode; public UrlDeserializedState(String protocol, String host, int port, String authority, String file, String ref, int hashCode) { this.protocol = protocol; this.host = host; this.port = port; this.authority = authority; this.file = file; this.ref = ref; this.hashCode = hashCode; } String getProtocol() { return protocol; } String getHost() { return host; } String getAuthority() { return authority; } int getPort() { return port; } String getFile() { return file; } String getRef() { return ref; } int getHashCode() { return hashCode; } String reconstituteUrlString() { // pre-compute length of StringBuffer int len = protocol.length() + 1; if (authority != null && !authority.isEmpty()) len += 2 + authority.length(); if (file != null) { len += file.length(); } if (ref != null) len += 1 + ref.length(); StringBuilder result = new StringBuilder(len); result.append(protocol); result.append(":"); if (authority != null && !authority.isEmpty()) { result.append("//"); result.append(authority); } if (file != null) { result.append(file); } if (ref != null) { result.append("#"); result.append(ref); } return result.toString(); } }