Getting java.lang.StringIndexOutOfBoundsException while parsing content between RSS tags

Question

I have a piece of content which has both html and rss, I would like to separate them and store in individual strings. So, I am trying to parse them based on their start and close tags and grab content between rss /rss .

Code works fine for html & /html. However I am seeing errors for rss & /rss.

Below is my code snippet.

// parse the responseStr to html
html = responseStr.substring(responseStr.indexOf("<html>"),
responseStr.lastIndexOf("</html>") + 7);
System.out.println("html string"+html );

Can someone please guide me what is wrong with the below code?

// parse the responseStr to rss
rss = responseStr.substring(responseStr.indexOf("<rss version="2.0">"),
responseStr.lastIndexOf("</rss>") + 6);
System.out.println("rss string = "+rss );

I get the below exception:

  java.lang.StringIndexOutOfBoundsException
    at java.lang.String.substring(String.java:1093)

What do you mean by I am seeing errors - Also, can you post the text you're trying to parse? — Mike Christensen
– Mike Christensen, Commented Aug 26, 2013 at 18:13
why not use a library? an xml parser at the very least would allow you to use xpath — radai
– radai, Commented Aug 26, 2013 at 18:13
The above code works for me if your input string is <rss> ... </rss>. Please post your input string. — Sotirios Delimanolis
– Sotirios Delimanolis, Commented Aug 26, 2013 at 18:18
chances are responseStr.lastIndexOf("</rss>") + 6 doesn't exist — 0x6C38
– 0x6C38, Commented Aug 26, 2013 at 18:20

Luke Willis · Accepted Answer · 2013-08-26 18:19:45Z

4

It is likely that your call to substring is being passed invalid indexes for your responseStr. You need to verify that your string actually contains the <rss> and </rss> tags before you call substring.

Try this:

String result;
int start = responseStr.indexOf("<rss>");
int end = responseStr.lastIndexOf("</rss>");

if (start != -1 && end != -1)
{
  result = "rss string = " + responseStr.substring(start, end + 6);
}
else
{
  result = "rss string not found";
}

System.out.println(result);

From the JavaDocs for String.indexOf, we know that if the string does not occur, -1 will be returned.

answered Aug 26, 2013 at 18:19

Luke Willis

8,5694 gold badges49 silver badges80 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

smiley Over a year ago

I do have rss string, however, when I use your code it prints rss string not found.

Luke Willis Over a year ago

@smiley If "rss string not found" is being printed, then one or both of the rss tags are missing. You need to inspect your string. You can also alter the above code to tell you which of the tags (opening or closing) is missing specifically.

smiley Over a year ago

ah.. I just noticed I am getting rss tag as <rss version="2.0"> and not as <rss> as someone mentioned above. How do I specify it in the code? I think I might need escape characters since I am not able to use version="2.0" directly.

smiley Over a year ago

Thank you very much Luke! I tried this, I know its pretty crude -- responseStr.indexOf("<rss version=") this worked for me though :) Thanks for all your help!

Luke Willis Over a year ago

If you're going to just use indexOf, I would recommend using "<rss" as your search string, rather than "<rss version=".

|

Khinsu · Accepted Answer · 2013-08-26 18:30:10Z

3

I think it would be easier by using

StringUtils.substringsBetween(String str,String open,String close)

javadoc

apache commons

Example:

String[] rss= StringUtils.substringsBetween(testHtml, "<rss>", "</rss>");
    for (String s : rss) {
        System.out.println("td rss:" + rss); 
}

public static String substringBetween(String str, String open, String close) {
    if (str == null || open == null || close == null) {
        return null;
    }
    int start = str.indexOf(open);
    if (start != INDEX_NOT_FOUND) {
        int end = str.indexOf(close, start + open.length());
        if (end != INDEX_NOT_FOUND) {
            return str.substring(start + open.length(), end);
        }
    }
    return null;
}

edited Aug 26, 2013 at 18:30

answered Aug 26, 2013 at 18:20

Khinsu

1,48711 silver badges27 bronze badges

Comments

Prashant Bhate · Accepted Answer · 2013-08-26 19:51:52Z

2

I would recommend xml parser though instead of below code

public static void main(String[] args) {
    String responseStr = "<rss ...>------content-----</rss>";
    int start = responseStr.indexOf("<rss");
    String content = null;
    if (start != -1) {
        start = responseStr.indexOf(">", start);
        if (start != -1) {
            int end = responseStr.lastIndexOf("</rss>");
            if (end != -1) {
                content = responseStr.substring(start + 1, end);
            }
        }
    }
    if (content != null)
        System.out.println(content);
    else
        System.err.println("Content not found");

}

Output

------content-----

answered Aug 26, 2013 at 19:51

Prashant Bhate

11.2k9 gold badges51 silver badges84 bronze badges

Collectives™ on Stack Overflow

Getting java.lang.StringIndexOutOfBoundsException while parsing content between RSS tags

3 Answers 3

7 Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

7 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related