Not able to validate the string via regex in java?

Question

I want to validate the string {233}{232}{112}{3232} with regex in java. I am using Pattern.compile("\\{([^\\}]*.?)\\}") but I'm not able to validate this string.

Here in the string, multiple ids are divided by the curly braces and the ID must be numeric.

Some test cases:

Test case 1: {122}{323} //true

Test case 2: {122}323} //false

Test case 3: {122323} //true

Test case 4: {122},{323} //false

Test case 5: {xx}{YY} //false

Can anyone help me on this? Your help will be really appreciated.

Pattern.compile("(\\{([^{}]*.?)\\})*") perhaps?

Maurice Perry
– Maurice Perry

2018-03-26 05:51:52 +00:00
Commented Mar 26, 2018 at 5:51 — Maurice Perry
– Maurice Perry, Commented Mar 26, 2018 at 5:51

Tim Biegeleisen · Accepted Answer · 2018-03-26 05:57:28Z

2

Your pattern is off, you should be using this:

(?:\{\\d*\})+

You seem to have some confusion about how to tell the regex engine to capture everything up until the first closing bracket. One could use [^}]*, but one could have also used lazy dot .*?. Your code appears to be using both, sort of. In this case though, we can just state take any number of digits, because a digit is by definition not a closing brace.

Full code:

String input = "{233}{232}{112}{3232}";

if (input.matches("(?:\\{\\d*\\})+")) {
    System.out.println("Match!");
}

Demo

edited Mar 26, 2018 at 5:57

answered Mar 26, 2018 at 5:51

Tim Biegeleisen

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3 Comments

Sean F Over a year ago

This does still pass the {xx}{YY} test that he stated should fail, it should also be checking that it is also a digit (?:\{[^}\D]*\})+

Tim Biegeleisen Over a year ago

@PraveenRawat My name isn't Tin, but appreciate the feedback.

Praveen Rawat Over a year ago

sorry @TimBiegeleisen for spell mistake

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