在Java中使用正则表达式查找和替换URL

Question

I am trying to replace a url with regex using String.replace and the code is below

public class Test {
    public static void main(String[] args) {
        String test = "https://google.com";
        //String regex = "\\b(https?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]";
        String regex = "(http?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]"; // does not match <http://google.com>

        String newText = test.replace(regex, "");
        System.out.println(newText);
    }
}

I have looked into several questions on it in SO but it does not replace the pattern. Can someone please tell me how do i achieve that?

Answer 1

String.replace() does not accept a regular expression. Use String.replaceAll instead:

String newText = test.replaceAll(regex, "");

As far as the regex is concerned, you should match the https as well:

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

Answer 2

You cannot use a regex with replace , use replaceAll instead, ie:

   String test = "something https://google.com something";
    try {
        String newText = test.replaceAll("(https?|ftp|file)://[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*[-a-zA-Z0-9+&@#/%=~_|]", "");
        System.out.println(newText);
    } catch (PatternSyntaxException ex) {
        // Syntax error in the regular expression
    } catch (IllegalArgumentException ex) {
        // Syntax error in the replacement text (unescaped $ signs?)
    } catch (IndexOutOfBoundsException ex) {
        // Non-existent backreference used the replacement text
    }

---

Output:

something  something

---

Live Demo:

http://ideone.com/Yi2hrb

---

Regex Explanation:

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

Options: Case sensitive; Exact spacing; Dot doesn’t match line breaks; ^$ don’t match at line breaks; Default line breaks; Regex syntax only

Match the regex below and capture its match into backreference number 1 «(https?|ftp|file)»
   Match this alternative «https?»
      Match the character string “http” literally «http»
      Match the character “s” literally «s?»
         Between zero and one times, as many times as possible, giving back as needed (greedy) «?»
   Or match this alternative «ftp»
      Match the character string “ftp” literally «ftp»
   Or match this alternative «file»
      Match the character string “file” literally «file»
Match the character string “://” literally «://»
Match a single character present in the list below «[-a-zA-Z0-9+&@#/%?=~_|!:,.;]*»
   Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»
   The literal character “-” «-»
   A character in the range between “a” and “z” «a-z»
   A character in the range between “A” and “Z” «A-Z»
   A character in the range between “0” and “9” «0-9»
   A single character from the list “+&@#/%?=~_|!:,.;” «+&@#/%?=~_|!:,.;»
Match a single character present in the list below «[-a-zA-Z0-9+&@#/%=~_|]»
   The literal character “-” «-»
   A character in the range between “a” and “z” «a-z»
   A character in the range between “A” and “Z” «A-Z»
   A character in the range between “0” and “9” «0-9»
   A single character from the list “+&@#/%=~_|” «+&@#/%=~_|»