JSF: How to replace "\\" in a string

Question

Suppose I have the string text\\, I need to replace \\ with /. I tried the following expression:

/*  str = "text\\"  */
<h:outputText value="#{fn:replace(str, '\\', '/')}" />

But I always run into the following exception:

Caused by: java.util.regex.PatternSyntaxException: Unexpected internal error near index 1
\
^
at java.util.regex.Pattern.error(Pattern.java:1924)
at java.util.regex.Pattern.compile(Pattern.java:1671)
at java.util.regex.Pattern.<init>(Pattern.java:1337)
at java.util.regex.Pattern.compile(Pattern.java:1022)
at java.lang.String.replaceAll(String.java:2210)
at com.sun.faces.facelets.tag.jstl.fn.JstlFunction.replace(JstlFunction.java:222)

I'd be very grateful if you could give me an advice.

UPDATE: Based on the answers below, I found out that the following expression will work:

<h:outputText value="#{fn:replace(str, '\\\\', '/')}" />

Best regards,

you want output of text\\ as text// or text/ ? – Fahim Parkar Jul 15 '12 at 14:34 — Fahim Parkar, Jul 15 '12 at 14:34
@FahimParkar: I'd like it to be `text/` – Mr.J4mes Jul 15 '12 at 17:55 — Mr.J4mes, Jul 15 '12 at 17:55

ioreskovic · Answer 1 · 2012-07-15T14:23:54.347

1

I believe you need to escape the backslashes. Try this: replace("\\\\", "/")

public class BackSlashEscaper {

    public static void main(String[] args) {

        String text = "text\\\\";
        System.out.println(text);

        System.out.println(text.replace("\\\\", "/"));
    }
}

Output:

text\\
text/

edited Jul 15 '12 at 14:23

answered Jul 15 '12 at 14:16

ioreskovic

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He needs to replace **2** not 1 backslash. – ioreskovic Jul 15 '12 at 14:19
> Suppose I have the string text\\, I need to replace \\ with /. – ioreskovic Jul 15 '12 at 14:20
Sorry, I need a solution that will work in an EL expression :(. – Mr.J4mes Jul 15 '12 at 17:58
The JSTL `fn:replace()` uses `String#replaceAll()` under the covers, not `String#replace()` (if you paid attention to the stacktrace, you would also have seen it). – BalusC Jul 16 '12 at 14:07
Stacktrace was added after my answer :D – ioreskovic Jul 16 '12 at 14:22

score 1 · Answer 2 · answered Jul 15 '12 at 14:26

1

Just to demonstrate with one backslash:

public static void main(String[] args)
    {
        String text = "text\\";

        System.out.println(text.replaceAll("\\\\","/"));
    }

answered Jul 15 '12 at 14:26

Shankhoneer Chakrovarty

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Sorry, I need a solution that will work in an EL expression :(. – Mr.J4mes Jul 15 '12 at 17:58
Thank you for your hint. I found out how to make it work with EL expression. – Mr.J4mes Jul 15 '12 at 18:37

score 1 · Accepted Answer · answered Jul 15 '12 at 14:37

1

Try this (haven't checked....)

<ui:param name="mydouble" value="\\\\"></ui:param>
<ui:param name="mysingle" value="/"></ui:param>
<h:outputText value="#{fn:replace(str, mydouble, mysingle)}" />

answered Jul 15 '12 at 14:37

Daniel

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I have just tried your solution. It resulted in the same exception :(. – Mr.J4mes Jul 15 '12 at 18:08
what namespace are you using ? `http://java.sun.com/jsp/jstl/core` ? is it JSF 2 app ? – Daniel Jul 15 '12 at 18:14
I'm sorry. It's working. I made some mistake while testing :D. Thank you. – Mr.J4mes Jul 15 '12 at 18:35

score 0 · Answer 4 · answered Jul 15 '12 at 14:39

public class TempClass {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String str = sc.next();
        System.out.println("before : "+str);
        String newstr = str.replace("\\", "/");
        System.out.println("after  : "+newstr);
    }
}

When I provide input as text\\ I get output as text//

before : text\\
after  : text//

JSF: How to replace "\\" in a string

4 Answers4

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