Regular expression to match URLs in Java

隐身守侯 提交于 2019-11-26 10:21:54
TomC

Try the following regex string instead. Your test was probably done in a case-sensitive manner. I have added the lowercase alphas as well as a proper string beginning placeholder.

String regex = "^(https?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]";

This works too:

String regex = "\\b(https?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]";

Note:

String regex = "<\\b(https?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]>"; // matches <http://google.com>

String regex = "<^(https?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]>"; // does not match <http://google.com>
Kamil Lelonek

The best way to do it now is:

android.util.Patterns.WEB_URL.matcher(linkUrl).matches();

EDIT: Code of Patterns from https://github.com/android/platform_frameworks_base/blob/master/core/java/android/util/Patterns.java :

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.util;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Commonly used regular expression patterns.
 */
public class Patterns {
    /**
     *  Regular expression to match all IANA top-level domains.
     *  List accurate as of 2011/07/18.  List taken from:
     *  http://data.iana.org/TLD/tlds-alpha-by-domain.txt
     *  This pattern is auto-generated by frameworks/ex/common/tools/make-iana-tld-pattern.py
     *
     *  @deprecated Due to the recent profileration of gTLDs, this API is
     *  expected to become out-of-date very quickly. Therefore it is now
     *  deprecated.
     */
    @Deprecated
    public static final String TOP_LEVEL_DOMAIN_STR =
        "((aero|arpa|asia|a[cdefgilmnoqrstuwxz])"
        + "|(biz|b[abdefghijmnorstvwyz])"
        + "|(cat|com|coop|c[acdfghiklmnoruvxyz])"
        + "|d[ejkmoz]"
        + "|(edu|e[cegrstu])"
        + "|f[ijkmor]"
        + "|(gov|g[abdefghilmnpqrstuwy])"
        + "|h[kmnrtu]"
        + "|(info|int|i[delmnoqrst])"
        + "|(jobs|j[emop])"
        + "|k[eghimnprwyz]"
        + "|l[abcikrstuvy]"
        + "|(mil|mobi|museum|m[acdeghklmnopqrstuvwxyz])"
        + "|(name|net|n[acefgilopruz])"
        + "|(org|om)"
        + "|(pro|p[aefghklmnrstwy])"
        + "|qa"
        + "|r[eosuw]"
        + "|s[abcdeghijklmnortuvyz]"
        + "|(tel|travel|t[cdfghjklmnoprtvwz])"
        + "|u[agksyz]"
        + "|v[aceginu]"
        + "|w[fs]"
        + "|(\u03b4\u03bf\u03ba\u03b9\u03bc\u03ae|\u0438\u0441\u043f\u044b\u0442\u0430\u043d\u0438\u0435|\u0440\u0444|\u0441\u0440\u0431|\u05d8\u05e2\u05e1\u05d8|\u0622\u0632\u0645\u0627\u06cc\u0634\u06cc|\u0625\u062e\u062a\u0628\u0627\u0631|\u0627\u0644\u0627\u0631\u062f\u0646|\u0627\u0644\u062c\u0632\u0627\u0626\u0631|\u0627\u0644\u0633\u0639\u0648\u062f\u064a\u0629|\u0627\u0644\u0645\u063a\u0631\u0628|\u0627\u0645\u0627\u0631\u0627\u062a|\u0628\u06be\u0627\u0631\u062a|\u062a\u0648\u0646\u0633|\u0633\u0648\u0631\u064a\u0629|\u0641\u0644\u0633\u0637\u064a\u0646|\u0642\u0637\u0631|\u0645\u0635\u0631|\u092a\u0930\u0940\u0915\u094d\u0937\u093e|\u092d\u093e\u0930\u0924|\u09ad\u09be\u09b0\u09a4|\u0a2d\u0a3e\u0a30\u0a24|\u0aad\u0abe\u0ab0\u0aa4|\u0b87\u0ba8\u0bcd\u0ba4\u0bbf\u0baf\u0bbe|\u0b87\u0bb2\u0b99\u0bcd\u0b95\u0bc8|\u0b9a\u0bbf\u0b99\u0bcd\u0b95\u0baa\u0bcd\u0baa\u0bc2\u0bb0\u0bcd|\u0baa\u0bb0\u0bbf\u0b9f\u0bcd\u0b9a\u0bc8|\u0c2d\u0c3e\u0c30\u0c24\u0c4d|\u0dbd\u0d82\u0d9a\u0dcf|\u0e44\u0e17\u0e22|\u30c6\u30b9\u30c8|\u4e2d\u56fd|\u4e2d\u570b|\u53f0\u6e7e|\u53f0\u7063|\u65b0\u52a0\u5761|\u6d4b\u8bd5|\u6e2c\u8a66|\u9999\u6e2f|\ud14c\uc2a4\ud2b8|\ud55c\uad6d|xn\\-\\-0zwm56d|xn\\-\\-11b5bs3a9aj6g|xn\\-\\-3e0b707e|xn\\-\\-45brj9c|xn\\-\\-80akhbyknj4f|xn\\-\\-90a3ac|xn\\-\\-9t4b11yi5a|xn\\-\\-clchc0ea0b2g2a9gcd|xn\\-\\-deba0ad|xn\\-\\-fiqs8s|xn\\-\\-fiqz9s|xn\\-\\-fpcrj9c3d|xn\\-\\-fzc2c9e2c|xn\\-\\-g6w251d|xn\\-\\-gecrj9c|xn\\-\\-h2brj9c|xn\\-\\-hgbk6aj7f53bba|xn\\-\\-hlcj6aya9esc7a|xn\\-\\-j6w193g|xn\\-\\-jxalpdlp|xn\\-\\-kgbechtv|xn\\-\\-kprw13d|xn\\-\\-kpry57d|xn\\-\\-lgbbat1ad8j|xn\\-\\-mgbaam7a8h|xn\\-\\-mgbayh7gpa|xn\\-\\-mgbbh1a71e|xn\\-\\-mgbc0a9azcg|xn\\-\\-mgberp4a5d4ar|xn\\-\\-o3cw4h|xn\\-\\-ogbpf8fl|xn\\-\\-p1ai|xn\\-\\-pgbs0dh|xn\\-\\-s9brj9c|xn\\-\\-wgbh1c|xn\\-\\-wgbl6a|xn\\-\\-xkc2al3hye2a|xn\\-\\-xkc2dl3a5ee0h|xn\\-\\-yfro4i67o|xn\\-\\-ygbi2ammx|xn\\-\\-zckzah|xxx)"
        + "|y[et]"
        + "|z[amw])";

    /**
     *  Regular expression pattern to match all IANA top-level domains.
     *  @deprecated This API is deprecated. See {@link #TOP_LEVEL_DOMAIN_STR}.
     */
    @Deprecated
    public static final Pattern TOP_LEVEL_DOMAIN =
        Pattern.compile(TOP_LEVEL_DOMAIN_STR);

    /**
     *  Regular expression to match all IANA top-level domains for WEB_URL.
     *  List accurate as of 2011/07/18.  List taken from:
     *  http://data.iana.org/TLD/tlds-alpha-by-domain.txt
     *  This pattern is auto-generated by frameworks/ex/common/tools/make-iana-tld-pattern.py
     *
     *  @deprecated This API is deprecated. See {@link #TOP_LEVEL_DOMAIN_STR}.
     */
    @Deprecated
    public static final String TOP_LEVEL_DOMAIN_STR_FOR_WEB_URL =
        "(?:"
        + "(?:aero|arpa|asia|a[cdefgilmnoqrstuwxz])"
        + "|(?:biz|b[abdefghijmnorstvwyz])"
        + "|(?:cat|com|coop|c[acdfghiklmnoruvxyz])"
        + "|d[ejkmoz]"
        + "|(?:edu|e[cegrstu])"
        + "|f[ijkmor]"
        + "|(?:gov|g[abdefghilmnpqrstuwy])"
        + "|h[kmnrtu]"
        + "|(?:info|int|i[delmnoqrst])"
        + "|(?:jobs|j[emop])"
        + "|k[eghimnprwyz]"
        + "|l[abcikrstuvy]"
        + "|(?:mil|mobi|museum|m[acdeghklmnopqrstuvwxyz])"
        + "|(?:name|net|n[acefgilopruz])"
        + "|(?:org|om)"
        + "|(?:pro|p[aefghklmnrstwy])"
        + "|qa"
        + "|r[eosuw]"
        + "|s[abcdeghijklmnortuvyz]"
        + "|(?:tel|travel|t[cdfghjklmnoprtvwz])"
        + "|u[agksyz]"
        + "|v[aceginu]"
        + "|w[fs]"
        + "|(?:\u03b4\u03bf\u03ba\u03b9\u03bc\u03ae|\u0438\u0441\u043f\u044b\u0442\u0430\u043d\u0438\u0435|\u0440\u0444|\u0441\u0440\u0431|\u05d8\u05e2\u05e1\u05d8|\u0622\u0632\u0645\u0627\u06cc\u0634\u06cc|\u0625\u062e\u062a\u0628\u0627\u0631|\u0627\u0644\u0627\u0631\u062f\u0646|\u0627\u0644\u062c\u0632\u0627\u0626\u0631|\u0627\u0644\u0633\u0639\u0648\u062f\u064a\u0629|\u0627\u0644\u0645\u063a\u0631\u0628|\u0627\u0645\u0627\u0631\u0627\u062a|\u0628\u06be\u0627\u0631\u062a|\u062a\u0648\u0646\u0633|\u0633\u0648\u0631\u064a\u0629|\u0641\u0644\u0633\u0637\u064a\u0646|\u0642\u0637\u0631|\u0645\u0635\u0631|\u092a\u0930\u0940\u0915\u094d\u0937\u093e|\u092d\u093e\u0930\u0924|\u09ad\u09be\u09b0\u09a4|\u0a2d\u0a3e\u0a30\u0a24|\u0aad\u0abe\u0ab0\u0aa4|\u0b87\u0ba8\u0bcd\u0ba4\u0bbf\u0baf\u0bbe|\u0b87\u0bb2\u0b99\u0bcd\u0b95\u0bc8|\u0b9a\u0bbf\u0b99\u0bcd\u0b95\u0baa\u0bcd\u0baa\u0bc2\u0bb0\u0bcd|\u0baa\u0bb0\u0bbf\u0b9f\u0bcd\u0b9a\u0bc8|\u0c2d\u0c3e\u0c30\u0c24\u0c4d|\u0dbd\u0d82\u0d9a\u0dcf|\u0e44\u0e17\u0e22|\u30c6\u30b9\u30c8|\u4e2d\u56fd|\u4e2d\u570b|\u53f0\u6e7e|\u53f0\u7063|\u65b0\u52a0\u5761|\u6d4b\u8bd5|\u6e2c\u8a66|\u9999\u6e2f|\ud14c\uc2a4\ud2b8|\ud55c\uad6d|xn\\-\\-0zwm56d|xn\\-\\-11b5bs3a9aj6g|xn\\-\\-3e0b707e|xn\\-\\-45brj9c|xn\\-\\-80akhbyknj4f|xn\\-\\-90a3ac|xn\\-\\-9t4b11yi5a|xn\\-\\-clchc0ea0b2g2a9gcd|xn\\-\\-deba0ad|xn\\-\\-fiqs8s|xn\\-\\-fiqz9s|xn\\-\\-fpcrj9c3d|xn\\-\\-fzc2c9e2c|xn\\-\\-g6w251d|xn\\-\\-gecrj9c|xn\\-\\-h2brj9c|xn\\-\\-hgbk6aj7f53bba|xn\\-\\-hlcj6aya9esc7a|xn\\-\\-j6w193g|xn\\-\\-jxalpdlp|xn\\-\\-kgbechtv|xn\\-\\-kprw13d|xn\\-\\-kpry57d|xn\\-\\-lgbbat1ad8j|xn\\-\\-mgbaam7a8h|xn\\-\\-mgbayh7gpa|xn\\-\\-mgbbh1a71e|xn\\-\\-mgbc0a9azcg|xn\\-\\-mgberp4a5d4ar|xn\\-\\-o3cw4h|xn\\-\\-ogbpf8fl|xn\\-\\-p1ai|xn\\-\\-pgbs0dh|xn\\-\\-s9brj9c|xn\\-\\-wgbh1c|xn\\-\\-wgbl6a|xn\\-\\-xkc2al3hye2a|xn\\-\\-xkc2dl3a5ee0h|xn\\-\\-yfro4i67o|xn\\-\\-ygbi2ammx|xn\\-\\-zckzah|xxx)"
        + "|y[et]"
        + "|z[amw]))";

    /**
     * Good characters for Internationalized Resource Identifiers (IRI).
     * This comprises most common used Unicode characters allowed in IRI
     * as detailed in RFC 3987.
     * Specifically, those two byte Unicode characters are not included.
     */
    public static final String GOOD_IRI_CHAR =
        "a-zA-Z0-9\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF";

    public static final Pattern IP_ADDRESS
        = Pattern.compile(
            "((25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}|[1-9][0-9]|[1-9])\\.(25[0-5]|2[0-4]"
            + "[0-9]|[0-1][0-9]{2}|[1-9][0-9]|[1-9]|0)\\.(25[0-5]|2[0-4][0-9]|[0-1]"
            + "[0-9]{2}|[1-9][0-9]|[1-9]|0)\\.(25[0-5]|2[0-4][0-9]|[0-1][0-9]{2}"
            + "|[1-9][0-9]|[0-9]))");

    /**
     * RFC 1035 Section 2.3.4 limits the labels to a maximum 63 octets.
     */
    private static final String IRI
        = "[" + GOOD_IRI_CHAR + "]([" + GOOD_IRI_CHAR + "\\-]{0,61}[" + GOOD_IRI_CHAR + "]){0,1}";

    private static final String GOOD_GTLD_CHAR =
        "a-zA-Z\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF";
    private static final String GTLD = "[" + GOOD_GTLD_CHAR + "]{2,63}";
    private static final String HOST_NAME = "(" + IRI + "\\.)+" + GTLD;

    public static final Pattern DOMAIN_NAME
        = Pattern.compile("(" + HOST_NAME + "|" + IP_ADDRESS + ")");

    /**
     *  Regular expression pattern to match most part of RFC 3987
     *  Internationalized URLs, aka IRIs.  Commonly used Unicode characters are
     *  added.
     */
    public static final Pattern WEB_URL = Pattern.compile(
        "((?:(http|https|Http|Https|rtsp|Rtsp):\\/\\/(?:(?:[a-zA-Z0-9\\$\\-\\_\\.\\+\\!\\*\\'\\(\\)"
        + "\\,\\;\\?\\&\\=]|(?:\\%[a-fA-F0-9]{2})){1,64}(?:\\:(?:[a-zA-Z0-9\\$\\-\\_"
        + "\\.\\+\\!\\*\\'\\(\\)\\,\\;\\?\\&\\=]|(?:\\%[a-fA-F0-9]{2})){1,25})?\\@)?)?"
        + "(?:" + DOMAIN_NAME + ")"
        + "(?:\\:\\d{1,5})?)" // plus option port number
        + "(\\/(?:(?:[" + GOOD_IRI_CHAR + "\\;\\/\\?\\:\\@\\&\\=\\#\\~"  // plus option query params
        + "\\-\\.\\+\\!\\*\\'\\(\\)\\,\\_])|(?:\\%[a-fA-F0-9]{2}))*)?"
        + "(?:\\b|$)"); // and finally, a word boundary or end of
                        // input.  This is to stop foo.sure from
                        // matching as foo.su

    public static final Pattern EMAIL_ADDRESS
        = Pattern.compile(
            "[a-zA-Z0-9\\+\\.\\_\\%\\-\\+]{1,256}" +
            "\\@" +
            "[a-zA-Z0-9][a-zA-Z0-9\\-]{0,64}" +
            "(" +
                "\\." +
                "[a-zA-Z0-9][a-zA-Z0-9\\-]{0,25}" +
            ")+"
        );

    /**
     * This pattern is intended for searching for things that look like they
     * might be phone numbers in arbitrary text, not for validating whether
     * something is in fact a phone number.  It will miss many things that
     * are legitimate phone numbers.
     *
     * <p> The pattern matches the following:
     * <ul>
     * <li>Optionally, a + sign followed immediately by one or more digits. Spaces, dots, or dashes
     * may follow.
     * <li>Optionally, sets of digits in parentheses, separated by spaces, dots, or dashes.
     * <li>A string starting and ending with a digit, containing digits, spaces, dots, and/or dashes.
     * </ul>
     */
    public static final Pattern PHONE
        = Pattern.compile(                      // sdd = space, dot, or dash
                "(\\+[0-9]+[\\- \\.]*)?"        // +<digits><sdd>*
                + "(\\([0-9]+\\)[\\- \\.]*)?"   // (<digits>)<sdd>*
                + "([0-9][0-9\\- \\.]+[0-9])"); // <digit><digit|sdd>+<digit>

    /**
     *  Convenience method to take all of the non-null matching groups in a
     *  regex Matcher and return them as a concatenated string.
     *
     *  @param matcher      The Matcher object from which grouped text will
     *                      be extracted
     *
     *  @return             A String comprising all of the non-null matched
     *                      groups concatenated together
     */
    public static final String concatGroups(Matcher matcher) {
        StringBuilder b = new StringBuilder();
        final int numGroups = matcher.groupCount();

        for (int i = 1; i <= numGroups; i++) {
            String s = matcher.group(i);

            if (s != null) {
                b.append(s);
            }
        }

        return b.toString();
    }

    /**
     * Convenience method to return only the digits and plus signs
     * in the matching string.
     *
     * @param matcher      The Matcher object from which digits and plus will
     *                     be extracted
     *
     * @return             A String comprising all of the digits and plus in
     *                     the match
     */
    public static final String digitsAndPlusOnly(Matcher matcher) {
        StringBuilder buffer = new StringBuilder();
        String matchingRegion = matcher.group();

        for (int i = 0, size = matchingRegion.length(); i < size; i++) {
            char character = matchingRegion.charAt(i);

            if (character == '+' || Character.isDigit(character)) {
                buffer.append(character);
            }
        }
        return buffer.toString();
    }

    /**
     * Do not create this static utility class.
     */
    private Patterns() {}
}
billjamesdev

I'll try a standard "Why are you doing it this way?" answer... Do you know about java.net.URL?

URL url = new URL(stringURL);

The above will throw a MalformedURLException if it can't parse the URL.

The problem with all suggested approaches: all RegEx is validating

All RegEx -based code is over-engineered: it will find only valid URLs! As a sample, it will ignore anything starting with "http://" and having non-ASCII characters inside.

Even more: I have encountered 1-2-seconds processing times (single-threaded, dedicated) with Java RegEx package (filtering Email addresses from text) for very small and simple sentences, nothing specific; possibly bug in Java 6 RegEx...

Simplest/Fastest solution would be to use StringTokenizer to split text into tokens, to remove tokens starting with "http://" etc., and to concatenate tokens into text again.

If you want to filter Emails from text (because later on you will do NLP staff etc) - just remove all tokens containing "@" inside.

This is simple text where RegEx of Java 6 fails. Try it in divverent variants of Java. It takes about 1000 milliseconds per RegEx call, in a long running single threaded test application:

pattern = Pattern.compile("[A-Za-z0-9](([_\\.\\-]?[a-zA-Z0-9]+)*)@([A-Za-z0-9]+)(([\\.\\-]?[a-zA-Z0-9]+)*)\\.([A-Za-z]{2,})", Pattern.CASE_INSENSITIVE);

"Avalanna is such a sweet little girl! It would b heartbreaking if cancer won. She's so precious! #BeliebersPrayForAvalanna");
"@AndySamuels31 Hahahahahahahahahhaha lol, you don't look like a girl hahahahhaahaha, you are... sexy.";

Do not rely on regular expressions if you only need to filter words with "@", "http://", "ftp://", "mailto:"; it is huge engineering overhead.

If you really want to use RegEx with Java, try Automaton

In line with billjamesdev answer, here is another approach to validate an URL without using a RegEx:

From Apache Commons Validator lib, look at class UrlValidator. Some example code:

Construct a UrlValidator with valid schemes of "http", and "https".

String[] schemes = {"http","https"}.
UrlValidator urlValidator = new UrlValidator(schemes);
if (urlValidator.isValid("ftp://foo.bar.com/")) {
   System.out.println("url is valid");
} else {
   System.out.println("url is invalid");
}

prints "url is invalid"

If instead the default constructor is used.

UrlValidator urlValidator = new UrlValidator();
if (urlValidator.isValid("ftp://foo.bar.com/")) {
   System.out.println("url is valid");
} else {
   System.out.println("url is invalid");
}

prints out "url is valid"

This works too:

String regex = "\\b(https?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]";

Note:

String regex = "<\\b(https?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]>"; // matches <http://google.com>

String regex = "<^(https?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]>"; // does not match <http://google.com>

So probably the first one is more useful for general use.

Abhiraj
((http?|https|ftp|file)://)?((W|w){3}.)?[a-zA-Z0-9]+\.[a-zA-Z]+

check here:- https://www.freeformatter.com/java-regex-tester.html#ad-output

It sorts out theses entries correctly

When using regular expressions from RegexBuddy's library, make sure to use the same matching modes in your own code as the regex from the library. If you generate a source code snippet on the Use tab, RegexBuddy will automatically set the correct matching options in the source code snippet. If you copy/paste the regex, you have to do that yourself.

In this case, as others pointed out, you missed the case insensitivity option.

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