JSP JSTL funciton fn:split is not working properly

Question

Today, I come across one issue and need your help to fix it.

I am trying to split the string using JSTL fn:split function that is likewise,

<c:set var="stringArrayName" value="${fn:split(element, '~$')}" />

Actual String :- "abc~$pqr$xyz"

Expected Result :-

abc 
pqr$xyz

only 2-string part expecting, but it gives

abc
pqr
xyz

here, total 3-string parts returning, which is wrong.

NOTE :- I have added <%@taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%> at the top of JSP.

any help really appreciates!!

Answer 1

JSTL split not work like the Java split you can check the difference from the code source :

org.apache.taglibs.standard.functions.Functions.split

public static String[] split(String input, String delimiters) {
    String[] array;
    if (input == null) {
        input = "";
    }
    if (input.length() == 0) {
        array = new String[1];
        array[0] = "";
        return array;
    }

    if (delimiters == null) {
        delimiters = "";
    }

    StringTokenizer tok = new StringTokenizer(input, delimiters);
    int count = tok.countTokens();
    array = new String[count];
    int i = 0;
    while (tok.hasMoreTokens()) {
        array[i++] = tok.nextToken();
    }
    return array;
}

java.lang.String.split

public String[] split(String regex, int limit) {
    return Pattern.compile(regex).split(this, limit);
}

So it's clearly that fn:split use StringTokenizer

    ...
    StringTokenizer tok = new StringTokenizer(input, delimiters);
    int count = tok.countTokens();
    array = new String[count];
    int i = 0;
    while (tok.hasMoreTokens()) {
        array[i++] = tok.nextToken();
    }
    ...

Not like java.lang.String.split which use regular expression

return Pattern.compile(regex).split(this, limit);
//-----------------------^

from the StringTokenizer documentation it says :

Constructs a string tokenizer for the specified string. The characters in the delim argument are the delimiters for separating tokens. Delimiter characters themselves will not be treated as tokens.

How `fn:split` exactly work?

It split on each character in the delimiter, in your case you have two characters ~ and $ so if your string is abc~$pqr$xyz it will split it like this :

abc~$pqr$xyz
   ^^   ^

1st split :

abc
$pqr$xyz

2nd split :

abc
pqr$xyz

3rd split :

abc
pqr
xyz

---

Solution

use split in your Servlet instead of JSTL

for example :

String[] array = "abc~$pqr$xyz".split("~\\$");