使用正则表达式获取 UNSPSC 中的商品级别

Question

I have got a scenario, where i need to fetch UNSPSC commodity level using regular expression and get level as..

each UNSPSC code is of 8 digit ..

Ist Level :XX 00 00 00

2nd Level :XX XX 00 00

3rd Level :XX XX XX 00

4th Level :XX XX XX XX.

Is thery any way to get level using Single Regular Expression, I was using, ((.)+)00 ... for each level match.

Not sure how to do it. Thanks.

Answer 1

Your regex ((.)+)00 matches 1+ times any character followed by 00 which does not take 8 digits into account. For the fourth level you want a match that does not end with 00 .

If you can not have 4 pairs of 2 times a zero, and 2 times a zero can not occur before not 2 times a zero you might use an alternation with capturing groups. Then check in the matcher if group 1, 2 or 3 exists to get level 1, 2 or 3. If there is a match and there is no group, then you will have level 4.

^(?:(0[1-9]|[1-9][0-9])0{6}|(0[1-9]|[1-9][0-9]){2}0{4}|((?:0[1-9]|[1-9][0-9])){3}00|(?:0[1-9]|[1-9][0-9]){4})$

Regex demo

Explanation

• ^ Start of the string
• (?: Non capturing group
  • (0[1-9]|[1-9][0-9])0{6} Match 01-99 followed by 6 times a 0
  • | Or
  • (0[1-9]|[1-9][0-9]){2}0{4} Match 2 times 01-99 followed by 4 times a zero
  • | Or
  • (?:(?:0[1-9]|[1-9][0-9])){3}00 Match 3 times 01-99 followed by 2 times a zero
  • | Or
  • (0[1-9]|[1-9][0-9]){4}) Match 4 times 01-99
• ) Close non capturing group
• $ End of the string

For example:

while (matcher.find()) {
    System.out.println("Full match: " + matcher.group(0));
        if (null != matcher.group(1)) {
            System.out.println("Level 1");
        } else if (null != matcher.group(2)) {
            System.out.println("Level 2");
        } else if (null != matcher.group(3)) {
            System.out.println("Level 3");
        } else {
            System.out.println("Level 4");
        }   
}

Output:

Full match: 01000000
Level 1
Full match: 10000000
Level 1
Full match: 99990000
Level 2
Full match: 99999900
Level 3
Full match: 55555555
Level 4

Java demo