Java中用于匹配URL的正则表达式

100

在使用正则表达式时,我使用 RegexBuddy。从它的库中复制了匹配 URL 的正则表达式。我在 RegexBuddy 中进行了成功的测试。但是,当我将其复制为 Java 的 String 格式并粘贴到 Java 代码中时,它就无法工作了。以下类会打印false

public class RegexFoo {

    public static void main(String[] args) {
        String regex = "\\b(https?|ftp|file)://[-A-Z0-9+&@#/%?=~_|!:,.;]*[-A-Z0-9+&@#/%=~_|]";
        String text = "http://google.com";
        System.out.println(IsMatch(text,regex));
}

    private static boolean IsMatch(String s, String pattern) {
        try {
            Pattern patt = Pattern.compile(pattern);
            Matcher matcher = patt.matcher(s);
            return matcher.matches();
        } catch (RuntimeException e) {
        return false;
    }       
}   
}

有人知道我做错了什么吗?


5
Sergio,请不要捕获RuntimeException。这可能会引入微妙的错误,并且总体上是不好的做法。如果你只想忽略表达式非法的情况,可以使用} catch(PatternSyntaxException pse){}代替。请参见第57条:http://java.sun.com/docs/books/effective/。 - OscarRyz
或者,您可以使用Pattern patt = Pattern.compile(pattern, Pattern.CASE_INSENSITIVE);来避免更改正则表达式以匹配大写和小写字母。 - jm4
我知道这已经很老了('08),但对于任何遇到类似问题的人来说,RegexBuddy有一个“使用”选项卡。确保您首先选择Java 7风格,然后在“使用”面板中,您可以让它为您的特定情况生成Java代码。这对我非常有效。 - Daniel F
11个回答

116

请尝试使用以下正则表达式字符串。您的测试可能是以区分大小写的方式进行的。我已添加小写字母以及适当的字符串开头占位符。

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

这也可以工作:

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

注意:

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>

1
使用您的正则表达式,我也得到了false。 - Sergio del Amo
你看到我最后的编辑了吗?我误按了字符串的开头。我刚刚将它复制到Eclipse中,结果是“true”。 - TomC
1
谢谢,这是我第一次在StackOverflow上看到评论的实用性。 - Sergio del Amo
1
没问题。如果你正在使用Eclipse,我喜欢使用这里提供的RegEx Tester插件http://www.brosinski.com/regex/。 - TomC
如果URL中的某个参数包含$符号,则此方法会失败。 - Lucke
显示剩余3条评论

104
现在最好的方法是:
android.util.Patterns.WEB_URL.matcher(linkUrl).matches();

编辑:从https://github.com/android/platform_frameworks_base/blob/master/core/java/android/util/Patterns.java获取的Patterns代码:

/*
 * 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() {}
}

3
谢谢你! +1 给你。这是很棒的代码!大家都在尝试使用复杂的正则表达式,而其实它可以这么简单。太棒了! - Kevin van Mierlo
9
除了原帖作者正在寻找一个Java解决方案而不是一个特定于Android的解决方案(很容易忘记查看问题的特定标签),这个回答还是有价值的,对于那些编写Android代码的人来说是一个好东西,所以我点了赞。 - indivisible
3
幸运的是,Android 是开源的,你可以从 https://github.com/android/platform_frameworks_base/blob/master/core/java/android/util/Patterns.java 获取代码 :) - EpicPandaForce
4
@EpicPandaForce 我认为你的评论是唯一让这个答案变得可接受/有帮助的,因为问题是在寻找“Java”解决方案,而不是“Android”。 - Don Cheadle
4
它没有检查URL是否以HTTP或HTTPS开头。我用www.www进行了测试,结果返回true。所以对我来说没有用处。 - FaisalAhmed
显示剩余6条评论

78

我试着回答一个标准的“你为什么要这样做?”的问题......你知道java.net.URL吗?

URL url = new URL(stringURL);

如果它无法解析URL,上述代码将抛出MalformedURLException异常。


2
我必须走过正则表达式之路。我在这里发布的内容尽可能简单,以使我的问题更清晰明了。在我的程序中,我在更复杂的正则表达式中使用了URL正则表达式。 - Sergio del Amo
1
很酷。我在正则表达式方面没有更好的答案,所以我想发表一个替代方案。虽然我没想到会因此被踩。 - billjamesdev
3
你说得对,可能“down-ticked”有点太过了。“我会尝试标准的做法”听起来有点冒犯。 - Sergio del Amo
1
酷(抱歉,快速度假)。是的,肯定不是那样打算的。我在这里经常看到这种情况,有时甚至会有所帮助。 - billjamesdev
18
如果端口<0或者无法理解协议,"new URL"将会抛出MalformedURLException异常。除此之外,它将不会捕获以下情况:http://1.2.3./ http://1.2.3.4.5/ http://1.2,3.4.5: 等任何其他情况都可以。 - David Newcomb
显示剩余3条评论

4
所有提出的方法都存在问题:所有的正则表达式都是验证性的。
所有基于正则表达式的代码都过度设计:它只能找到有效的URL!例如,它会忽略任何以"http://"开头并且内部包含非ASCII字符的内容。
更重要的是:我在使用Java RegEx包(从文本中过滤电子邮件地址)对非常小而简单的句子进行单线程处理时遇到了1-2秒的处理时间,没有特别的情况;可能是Java 6 RegEx中的错误......
最简单/最快的解决方案是使用StringTokenizer将文本拆分为标记,删除以“http://”等开头的标记,并将标记连接成文本。
如果您想从文本中过滤电子邮件(因为之后您将处理自然语言处理等内容)-只需删除包含“@”的所有标记。
这是一个简单的文本,在Java 6的正则表达式中失败。请在不同版本的Java中尝试。在长时间运行的单线程测试应用程序中,每个正则表达式调用大约需要1000毫秒。
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.";

如果你只需要过滤含有 "@", "http://", "ftp://", "mailto:" 的词汇,不要仅仅依赖正则表达式,因为这会带来巨大的工程开销。

如果你真的想在 Java 中使用正则表达式,请尝试 Automaton


Lol。自动机不支持捕获组。 - user1050755
6
我不理解你的关注点。接受的答案中的正则表达式实际上很适合验证URL。你似乎在嘲笑它,说“它只会找到有效的URL!”--这是OP问题的目标。我有什么没明白吗? - Don Cheadle

3

按照billjamesdev的答案,这里提供另一种验证URL的方法,不使用正则表达式:

Apache Commons Validator库中,查看UrlValidator类。以下是一些示例代码:

使用“http”和“https”作为有效协议构造一个UrlValidator。

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"

如果使用默认构造函数,则需要进行如下更改。
UrlValidator urlValidator = new UrlValidator();
if (urlValidator.isValid("ftp://foo.bar.com/")) {
   System.out.println("url is valid");
} else {
   System.out.println("url is invalid");
}

打印输出 "url is valid"


3

它无法处理特殊字符。 - Sankalp Kotewar
我需要正则表达式来从歌曲名称中删除URL。找不到一个合适的,或者说大多数都失败了,所以我发帖分享了对我有效的方法,在那些情况下可以使用 :) - Abhiraj
是的,确实如此。请在提供的链接上进行检查。 - Abhiraj

3

这也可以运行:

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

注意:
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>

因此,第一个选项对于一般使用可能更有用。


0

首先,一个正则表达式的例子:

regex = “((http|https)://)(www.)?” 
+ “[a-zA-Z0-9@:%._\\+~#?&//=]{2,256}\\.[a-z]” 
+ “{2,6}\\b([-a-zA-Z0-9@:%._\\+~#?&//=]*)”

*URL必须以http或https开头, *然后跟着://, *接着必须包含www., *然后是长度为(2,256)的子域名, *最后一部分包含像.com、.org等顶级域名。


在JAVA中

// Java program to check URL is valid or not
// using Regular Expression
 
import java.util.regex.*;
 
class GFG {
 
    // Function to validate URL
    // using regular expression
    public static boolean
    isValidURL(String url)
    {
        // Regex to check valid URL
        String regex = "((http|https)://)(www.)?"
              + "[a-zA-Z0-9@:%._\\+~#?&//=]"
              + "{2,256}\\.[a-z]"
              + "{2,6}\\b([-a-zA-Z0-9@:%"
              + "._\\+~#?&//=]*)";
 
        // Compile the ReGex
        Pattern p = Pattern.compile(regex);
 
        // If the string is empty
        // return false
        if (url == null) {
            return false;
        }
 
        // Find match between given string
        // and regular expression
        // using Pattern.matcher()
        Matcher m = p.matcher(url);
 
        // Return if the string
        // matched the ReGex
        return m.matches();
    }
 
    // Driver code
    public static void main(String args[])
    {
        String url
            = "https://www.superDev.org";
        if (isValidURL(url) == true) {
            System.out.println("Yes");
        }
        else
            System.out.println("NO");
    }
}

在Python 3中

# Python3 program to check
# URL is valid or not
# using regular expression
import re
 
# Function to validate URL
# using regular expression
def isValidURL(str):
 
    # Regex to check valid URL
    regex = ("((http|https)://)(www.)?" +
             "[a-zA-Z0-9@:%._\\+~#?&//=]" +
             "{2,256}\\.[a-z]" +
             "{2,6}\\b([-a-zA-Z0-9@:%" +
             "._\\+~#?&//=]*)")
     
    # Compile the ReGex
    p = re.compile(regex)
 
    # If the string is empty
    # return false
    if (str == None):
        return False
 
    # Return if the string
    # matched the ReGex
    if(re.search(p, str)):
        return True
    else:
        return False
 
# Driver code
 
# Test Case 1:
url = "https://www.superDev.org"
 
if(isValidURL(url) == True):
    print("Yes")
else:
    print("No")
 

0

这里提供一个URL解析器正则表达式的建议,它可以识别:

  • 协议
  • 主机
  • 端口
  • 路径(文档/文件夹)
  • GET参数
^(?>(?<protocol>[[:alpha:]]+(?>\:[[:alpha:]]+)*)\:\/\/)?(?<host>(?>[[:alnum:]]|[-_.])+)(?>\:(?<port>[[:digit:]]+))?(?<path>\/(?>[[:alnum:]]|[-_.\/])*)?(?>\?(?<request>(?>[[:alnum:]]+=[[:alnum:]]+)(?>\&(?>[[:alnum:]]+=[[:alnum:]]+))*))?$

这个正则表达式能够解析诸如此类的URL:

jdbc:hsqldb:hsql://localhost:91/index.

有很多方法可以设计URL正则表达式,因此我提出的这个可以轻松适应更准确的URL语法。

可以在以下页面上进行测试:https://regex101.com/r/Dy7HE0/5

请注意,本地API的正则表达式(例如java.util.regex)不支持智能字符类,如[[:alnum:]][[:alpha:]]

请改用\w\d


0

当使用RegexBuddy库中的正则表达式时,请确保在您自己的代码中使用与库中的正则表达式相同的匹配模式。如果您在“使用”选项卡上生成源代码片段,则RegexBuddy将自动在源代码片段中设置正确的匹配选项。如果您复制/粘贴正则表达式,则必须自己完成此操作。

在这种情况下,正如其他人指出的那样,您错过了不区分大小写的选项。


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