How to check if a string is of a specific pattern [closed]

Answer 1

public static void main(String[] args) throws Exception {
    String id = "TV1523";
    BufferedReader br = new BufferedReader((new InputStreamReader(System.in)));
    String tocompare = br.readLine();
    if(tocompare.equals(id)) { //do stuff

something like that, except you might wand to enclose the readLine() within a try catch instead :x

Answer 2

You should compare the string using a regular expression, for example:

str.matches("^[A-Z]{2}\\d{4}") will give you a boolean value as to whether it matches or not.

The regular expression works as follows:

^ Indicates that the following pattern needs to appear at the beginning of the string.
[A-Z] Indicates that the uppercase letters A-Z are required.
{2} Indicates that the preceding pattern is repeated twice (two A-Z characters).
\\d Indicates you expect a digit (0-9)
{4} Indicates the the preceding pattern is expected four times (4 digits).

Using this method, you can loop through any number of strings and check if they match the criteria given.

You should read up on regular expressions though, there are more efficient ways of storing the pattern if you are worried about performance.

Answer 3

You should have a closer look at regular expressions. A tutorial is e.g. here at regular-expressions.info.

An example for your Pattern could be

^[A-Z]{2}\d{4}$

you can see it here on Regexr.com a good place to test regular expressions online.

Here is java regex tutorial there you can see how you call them in Java.