Small problems splitting a string

Question

I have this string:

"http://my/website/collections/index.php?s=1&schema=http:/my/web/fe7cd50991b11f51050902sddaf3e042bd5467/idApp=19"

I want to extract this token from the string: fe7cd50991b11f51050902sddaf3e042bd5467

the website can vary, but the only think cannot vary is that the string token i must obtain always is on the left of "/idApp="

Which is the most efficient way to solve that?

thanks.

What're the ones that you've tried? – Sujay Sep 05 '12 at 08:23 — Sujay, Sep 05 '12 at 08:23

tgr · Accepted Answer · 2012-09-05T08:25:28.987

String url = "http://my/website/collections/index.php?s=1&schema=http:/my/web/fe7cd50991b11f51050902sddaf3e042bd5467/idApp=19";
String[] tokens = url.split("/");
String searched = tokens[array.length - 2];

This will work if the token is everytime the prelast. Otherwise you need to go through the Array and check if the current token matches your condition and take the token before. In code:

int tokenId = 0;
for (int i = 0; i < tokens.length; i++) {
  if (token[i].equals("/idApp=")) {
    tokenId = i - 1;
    break;
  }
}
String rightToken = tokens[tokenId];

score 2 · Answer 2 · answered Sep 05 '12 at 08:29

Assuming the token can only numbers and letters, you can use something like this.

It matches a sequence of numbers and letters, preceding the /idApp= string.

It is "efficient" in terms of being a standard, easy-to-read way to do that, but there may be more performance-efficient ways to do it, although you should think carefully about whether finding this string would really be a performance bottle-neck.

import java.util.regex.Matcher;
import java.util.regex.Pattern;


public class TestRegexp {
    public static void main(String args[]) {
        String text = "http://my/website/collections/index.php?s=1&schema=http:/my/web/fe7cd50991b11f51050902sddaf3e042bd5467/idApp=19";
        Pattern pattern = Pattern.compile("(\\w+)/idApp=");
        Matcher m = pattern.matcher(text);
        if (m.find()) {
            System.out.println(m.group(1)); 
        }

    }
}

Andrey Atapin · Answer 3 · 2012-09-05T08:50:39.350

1

You don't need regexp here. Absolutely. The task is just to cut a piece of string, don't over-complicate. Simplicity is the key.

int appIdPosition = url.lastIndexOf("/idApp=");
int slashBeforePosition = url.lastIndexOf("/", appIdPosition - 1);
String token = url.substring(slashBeforePosition + 1, appIdPosition);

edited Sep 05 '12 at 08:50

answered Sep 05 '12 at 08:31

Andrey Atapin

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score 0 · Answer 4 · edited Sep 27 '12 at 21:26

0

You could use the regex

These two packages will help you

java.util.regex.Matcher
java.util.regex.Pattern

edited Sep 27 '12 at 21:26

ScArcher2

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answered Sep 05 '12 at 08:23

hemmingway

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You might want to elaborate on your answer and provide the OP with a solution, rather than talk about available packages only :) – Sujay Sep 05 '12 at 08:25

score 0 · Answer 5 · answered Sep 05 '12 at 08:31

Simple 2 times split would work for multiple parameters. First split on "idApp" and then on /.

The following code would work even if there are multiple parameters after the idApp parameter.

String url = "http://my/website/collections/index.php?s=1&schema=http:/my/web/fe7cd50991b11f51050902sddaf3e042bd5467/idApp=19";
String[] tokens = url.split("idApp");
String[] leftPartTokens = tokens[0].split("/");
String searched = leftPartTokens[leftPartTokens.length - 1];
System.out.println(searched);

score 0 · Answer 6 · answered Sep 05 '12 at 08:44

0

When doing anything with strings, always look to:

http://commons.apache.org/lang/api-2.5/org/apache/commons/lang/StringUtils.html

Here is my answer...

public static void main(String[] args) {
    //Don't forget: import static org.apache.commons.lang.StringUtils.*;
    String url2 = "http://my/website/collections/index.php?s=1&schema=http:/my/web/fe7cd50991b11f51050902sddaf3e042bd5467/idApp=19";
    String result =  substringAfterLast("/", substringBeforeLast(url2,"/")) ;
    System.out.println(result);
}

answered Sep 05 '12 at 08:44

Nos

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Though the answer is completely valid, I wouldn't advise the OP to use static imports. [What is a good use case for static import of methods?](http://stackoverflow.com/q/420791/851811) – Xavi López Sep 05 '12 at 09:01
You're correct, the static import is not necessary but in my opinion it keeps the code less verbose and most IDE's will tell us where the code originates from. I normally do a static import of the StringUtils as I would tend to use it heavily and Oracle says "use it when you require frequent access to static members from one or two classes.". – Nos Sep 05 '12 at 10:43

Small problems splitting a string

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