java - find and replace substring between two pattern strings

Question

I have the following xml fragment as a string:

String str ="<xs:user>userName</xs:user><xs:password>userPassword</xs:password>
<xs:address>addressString</xs:address>";

What would be the best way to replace userPassword with xxxxxxx?

Edit: xs (namespace) can vary.

A boundary/special case: how does that XML fragment look if the password contains < ? — peter.petrov, Apr 11 '14 at 09:09

score 1 · Answer 1 · answered Apr 11 '14 at 09:05

1

Try using this:

String str2 = str.replaceFirst("<xs:password>.*?</xs:password>", "<xs:password>xxxxxxxxxx</xs:password>");`

answered Apr 11 '14 at 09:05

anirudh

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I wouldn't use the greedy `.*` here, but replace it with `.*?` – Joffrey Apr 11 '14 at 09:06

score 1 · Answer 2 · answered Apr 11 '14 at 09:06

1

This should do it. This is the most simple solution I can think of right now.

public static void main(String[] args) {
    String str = "aaaaa<xs:password>userPassword</xs:password>bbbbbbbbbb";
    String newPassword = "test";
    String s2 = str.replaceAll("<xs:password>[^<]*</xs:password>", "<xs:password>" + newPassword + "</xs:password>");
    System.out.println(s2);
}

answered Apr 11 '14 at 09:06

peter.petrov

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I would prefer @anirudh version, because yours excludes nested tags, so cannot be generalized, even if it is doing the job here. – Joffrey Apr 11 '14 at 09:09
+1 For the working solution, though. – Joffrey Apr 11 '14 at 09:14

score 0 · Answer 3 · answered Apr 11 '14 at 09:06

An oldschool crawl-through-the-string approch would be:

    String in =
            "<xs:user>userName</xs:user>" +
            "<xs:password>userPassword</xs:password>" +
            "<xs:address>addressString</xs:address>";

    int pwStart = in.indexOf("<xs:password>") + 13;
    int pwLen   = in.indexOf("</xs:password>") - pwStart;

    StringBuilder out = new StringBuilder();

    out.append(in.substring(0, in.indexOf("<xs:password>") + 13));
    for (int i = 0; i < pwLen; i++) {
        out.append("x");
    }
    out.append(in.substring(in.indexOf("</xs:password>")));

    System.out.printf("%s\n", in);
    System.out.printf("%s\n", out);

score 0 · Answer 4 · answered Apr 11 '14 at 09:16

In Java:

public static void replace(){

    String str =
            "<xs:user>userName</xs:user>" +
            "<xs:password>userPassword</xs:password>" +
            "<xs:address>addressString</xs:address>";

    String[] s = str.split("><");

    String[] t = s[1].split("password>");

    String[] a = t[1].split("</xs:");

    System.out.println(a[0]);

    String newS = s[0] + "><" + t[0] + "password>" + "YOUR XXXXXXX GOES HERE" + "</xs:" + a[1] + "><" + s[2];

    System.out.println(newS);

}

Hope this helps.

java - find and replace substring between two pattern strings

4 Answers4