Question

Suppose you’re dealing with data organized in the following format:

[123]="some string" [234]=999999999 [345]="some other string"

In Java, what would be the easiest way to split each by KV combination, where K is the tag (enclosed in [ ]).

Is there a Utils (Apache or other?) method you know off that lets you define a structure as shown above to help with iterating over it, instead of having to manually count and read data past and between [ ]?

What do we know?

• Each element will have a tag
• Each tag will be surrounded by [ ]
• Tag and value assigned to the tag will be separated by =
• Value will be there. No empty values allowed.
• Value may or may not be surrounded by quotes

Answer 1

Use a Pattern with regex "\\[(.*?)\\]=(.*?)( (?=\\[)|$)" to grab pairs at a time.
The only limitation is that the next term is assumed to start at a space followed by a [, so this character sequence may not appear within a value.

This code demonstrates:

public static void main(String[] args) {
    String input = "[123]=\"some string\" [234]=999999999 [345]=\"some other string\"";
    Pattern pattern = Pattern.compile("\\[(.*?)\\]=(.*?)( (?=\\[)|$)");
    Matcher matcher = pattern.matcher(input);
    while (matcher.find()) {
        String k = matcher.group(1);
        String v = matcher.group(2);
        System.out.println(k + "-->" + v);
    }
}

Output:

123-->"some string"
234-->999999999
345-->"some other string"