Java Regular Expression string match

Question

I need a help. I am writing a method which will return true if 1954 is in string images/deal/129277/1954-bonus.jpg. I can use string.contains but it won't be accurate always. Instead I want it to return true if 1954 is at exact place. Below sourceKey is images/deal/129277/1954-bonus.jpg and oldImageId is 1954.

Below code is not working.

private boolean keyMatches(String sourceKey, String oldImageId){
    Pattern pattern = Pattern.compile("(.*?)/(\\d+)/(\\d+)-(.*)");
    Matcher matcher = pattern.matcher(sourceKey);
    return oldImageId.equals(matcher.group(3));
}

you need to use find function.

Avinash Raj
– Avinash Raj

2015-02-25 14:07:09 +00:00
Commented Feb 25, 2015 at 14:07 — Avinash Raj
– Avinash Raj, Commented Feb 25, 2015 at 14:07

Avinash Raj · Accepted Answer · 2015-02-25 14:19:00Z

2

Seems like you want something like this,

String s = "images/deal/129277/1954-bonus.jpg";
String oldImageId = "1954";
Matcher m = Pattern.compile("(.*?)/(\\d+)/(\\d+)-(.*)").matcher(s);
if(m.find())
{
System.out.println(oldImageId.matches(m.group(3)));
}

Output:

true

edited Feb 25, 2015 at 14:19

answered Feb 25, 2015 at 14:11

Avinash Raj

175k32 gold badges247 silver badges289 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

guido Over a year ago

or better if (m.matches())

AlexR Over a year ago

why do you call find() into while loop? It is enought to call it once.

TheLostMind · Accepted Answer · 2015-02-25 14:09:33Z

1

Try something like this :

public static void main(String[] args) {
    String s = "images/deal/129277/1954-bonus.jpg";
    String s1 = "images/deal/1954/1911254-bonus.jpg";
    System.out.println(s.matches(".*/1954\\-.*"));
    System.out.println(s1.matches(".*/1954\\-.*"));
}

O/P:

true
false

answered Feb 25, 2015 at 14:09

TheLostMind

36.3k12 gold badges72 silver badges109 bronze badges

Comments

AlexR · Accepted Answer · 2015-02-25 14:13:01Z

0

I can see at least one mistake in your code. Matcher does not return any group unless you call find() or match() method before and these methods returned true.

So, your code should be modified as following:

Matcher matcher = pattern.matcher(sourceKey);
return matcher.find() ? oldImageId.equals(matcher.group(3)) : null;

I am leaving it to you to verify that your regex is indeed correct.

answered Feb 25, 2015 at 14:13

AlexR

116k16 gold badges137 silver badges216 bronze badges

Comments

Ravi K Thapliyal · Accepted Answer · 2015-02-25 14:32:00Z

0

Using regex lookahead and String#matches() your function could be a one-liner like

private boolean keyMatches(String sourceKey, String oldImageId){
    return sourceKey.matches(".*/(?!.*/)"+oldImageId+"-.*");
}

I tried the following tests with 1954 placed at various parts of the URL to try fool the regex.

System.out.println(keyMatches("images/deal/129277/1954-bonus.jpg", "1954"));
System.out.println(keyMatches("images/deal/1954-pics/129277-bonus.jpg", "1954"));
System.out.println(keyMatches("123-1954/1954-00/1954/129277-bonus.jpg", "1954"));
System.out.println(keyMatches("images/deal/129277/129277-1954-bonus.jpg", "1954"));

Output :

true
false
false
false

edited Feb 25, 2015 at 14:32

answered Feb 25, 2015 at 14:19

Ravi K Thapliyal

51.9k9 gold badges80 silver badges90 bronze badges

Collectives™ on Stack Overflow

Java Regular Expression string match

4 Answers 4

2 Comments

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

2 Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related