url.java

Tomcat 4.1与WebServer集成组件的源代码包.

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 *
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 * The Apache Software License, Version 1.1
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package org.apache.tomcat.util.net;


import java.io.Serializable;
import java.net.MalformedURLException;


/**
 * <p><strong>URL</strong> is designed to provide public APIs for parsing
 * and synthesizing Uniform Resource Locators as similar as possible to the
 * APIs of <code>java.net.URL</code>, but without the ability to open a
 * stream or connection.  One of the consequences of this is that you can
 * construct URLs for protocols for which a URLStreamHandler is not
 * available (such as an "https" URL when JSSE is not installed).</p>
 *
 * <p><strong>WARNING</strong> - This class assumes that the string
 * representation of a URL conforms to the <code>spec</code> argument
 * as described in RFC 2396 "Uniform Resource Identifiers: Generic Syntax":
 * <pre>
 *   &lt;scheme&gt;//&lt;authority&gt;&lt;path&gt;?&lt;query&gt;#&lt;fragment&gt;
 * </pre></p>
 *
 * <p><strong>FIXME</strong> - This class really ought to end up in a Commons
 * package someplace.</p>
 *
 * @author Craig R. McClanahan
 * @version $Revision: 1.2 $ $Date: 2002/06/14 05:34:23 $
 */

public final class URL implements Serializable {


    // ----------------------------------------------------------- Constructors


    /**
     * Create a URL object from the specified String representation.
     *
     * @param spec String representation of the URL
     *
     * @exception MalformedURLException if the string representation
     *  cannot be parsed successfully
     */
    public URL(String spec) throws MalformedURLException {

        this(null, spec);

    }


    /**
     * Create a URL object by parsing a string representation relative
     * to a specified context.  Based on logic from JDK 1.3.1's
     * <code>java.net.URL</code>.
     *
     * @param context URL against which the relative representation
     *  is resolved
     * @param spec String representation of the URL (usually relative)
     *
     * @exception MalformedURLException if the string representation
     *  cannot be parsed successfully
     */
    public URL(URL context, String spec) throws MalformedURLException {

        String original = spec;
        int i, limit, c;
        int start = 0;
        String newProtocol = null;
        boolean aRef = false;

        try {

            // Eliminate leading and trailing whitespace
            limit = spec.length();
            while ((limit > 0) && (spec.charAt(limit - 1) <= ' ')) {
                limit--;
            }
            while ((start < limit) && (spec.charAt(start) <= ' ')) {
                start++;
            }

            // If the string representation starts with "url:", skip it
            if (spec.regionMatches(true, start, "url:", 0, 4)) {
                start += 4;
            }

            // Is this a ref relative to the context URL?
            if ((start < spec.length()) && (spec.charAt(start) == '#')) {
                aRef = true;
            }

            // Parse out the new protocol
            for (i = start; !aRef && (i < limit) &&
                     ((c = spec.charAt(i)) != '/'); i++) {
                if (c == ':') {
                    String s = spec.substring(start, i).toLowerCase();
                    // Assume all protocols are valid
                    newProtocol = s;
                    start = i + 1;
                    break;
                }
            }

            // Only use our context if the protocols match
            protocol = newProtocol;
            if ((context != null) && ((newProtocol == null) ||
                 newProtocol.equalsIgnoreCase(context.getProtocol()))) {
                // 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.getPath() != null) &&
                    (context.getPath().startsWith("/")))
                    newProtocol = null;
                if (newProtocol == null) {
                    protocol = context.getProtocol();
                    authority = context.getAuthority();
                    userInfo = context.getUserInfo();
                    host = context.getHost();
                    port = context.getPort();
                    file = context.getFile();
                    int question = file.lastIndexOf("?");
                    if (question < 0)
                        path = file;
                    else
                        path = file.substring(0, question);
                }
            }

            if (protocol == null)
                throw new MalformedURLException("no protocol: " + original);

            // Parse out any ref portion of the spec
            i = spec.indexOf('#', start);
            if (i >= 0) {
                ref = spec.substring(i + 1, limit);
                limit = i;
            }

            // Parse the remainder of the spec in a protocol-specific fashion
            parse(spec, start, limit);
            if (context != null)
                normalize();


        } catch (MalformedURLException e) {
            throw e;
        } catch (Exception e) {
            throw new MalformedURLException(e.toString());
        }

    }





    /**
     * Create a URL object from the specified components.  The default port
     * number for the specified protocol will be used.
     *
     * @param protocol Name of the protocol to use
     * @param host Name of the host addressed by this protocol
     * @param file Filename on the specified host
     *
     * @exception MalformedURLException is never thrown, but present for
     *  compatible APIs
     */
    public URL(String protocol, String host, String file)
        throws MalformedURLException {

        this(protocol, host, -1, file);

    }


    /**
     * Create a URL object from the specified components.  Specifying a port
     * number of -1 indicates that the URL should use the default port for
     * that protocol.  Based on logic from JDK 1.3.1's
     * <code>java.net.URL</code>.
     *
     * @param protocol Name of the protocol to use
     * @param host Name of the host addressed by this protocol
     * @param port Port number, or -1 for the default port for this protocol
     * @param file Filename on the specified host
     *
     * @exception MalformedURLException is never thrown, but present for
     *  compatible APIs
     */
    public URL(String protocol, String host, int port, String file)
        throws MalformedURLException {

        this.protocol = protocol;
        this.host = host;
        this.port = port;

        int hash = file.indexOf('#');
        this.file = hash < 0 ? file : file.substring(0, hash);
        this.ref = hash < 0 ? null : file.substring(hash + 1);
        int question = file.lastIndexOf('?');
        if (question >= 0) {
            query = file.substring(question + 1);
            path = file.substring(0, question);
        } else
            path = file;

        if ((host != null) && (host.length() > 0))
            authority = (port == -1) ? host : host + ":" + port;

    }


    // ----------------------------------------------------- Instance Variables


    /**
     * The authority part of the URL.
     */
    private String authority = null;


    /**
     * The filename part of the URL.
     */
    private String file = null;


    /**
     * The host name part of the URL.
     */
    private String host = null;


    /**
     * The path part of the URL.
     */
    private String path = null;


    /**
     * The port number part of the URL.
     */
    private int port = -1;


    /**
     * The protocol name part of the URL.
     */
    private String protocol = null;


    /**
     * The query part of the URL.
     */
    private String query = null;


    /**
     * The reference part of the URL.
     */
    private String ref = null;


    /**
     * The user info part of the URL.
     */
    private String userInfo = null;


    // --------------------------------------------------------- Public Methods


    /**
     * Compare two URLs for equality.  The result is <code>true</code> if and
     * only if the argument is not null, and is a <code>URL</code> object
     * that represents the same <code>URL</code> as this object.  Two
     * <code>URLs</code> are equal if they have the same protocol and
     * reference the same host, the same port number on the host,
     * and the same file and anchor on the host.
     *
     * @param obj The URL to compare against
     */
    public boolean equals(Object obj) {

        if (obj == null)
            return (false);
        if (!(obj instanceof URL))
            return (false);
        URL other = (URL) obj;
        if (!sameFile(other))
            return (false);
        return (compare(ref, other.getRef()));

    }


    /**
     * Return the authority part of the URL.
     */
    public String getAuthority() {

        return (this.authority);

    }


    /**
     * Return the filename part of the URL.  <strong>NOTE</strong> - For
     * compatibility with <code>java.net.URL</code>, this value includes
     * the query string if there was one.  For just the path portion,
     * call <code>getPath()</code> instead.
     */
    public String getFile() {