Android Java String code optimization needed

Question

I have issue with parsing html data. Java's String.indexof() is extremelly slow. Could anyone suggest any solutions to significantly speed it up?

                      while (counter2 <= found)
                    {
                        number = Integer.toString(counter2);
                        start = page.indexOf("<result" + number + ">") + 8 + number.length();
                        end = page.indexOf("</result" + number + ">");
                        if (start > 0 && end > 0)
                        {
                            buffer = page.substring(start, end);
                        }
                        page = page.substring(end, page.length());
                        start = buffer.indexOf("<word>") + 6;
                        end = buffer.indexOf("</word>");
                        if (start > 0 && end > 0)
                        {
                            Word = buffer.substring(start, end);
                        }
                        start = buffer.indexOf("<vocabulary>") + 12;
                        end = buffer.indexOf("</vocabulary>");
                        if (start > 0 && end > 0)
                        {
                            Dictionary = buffer.substring(start, end);
                        }

                        start = buffer.indexOf("<id>") + 4;
                        end = buffer.indexOf("</id>");
                        if (start > 0 && end > 0)
                        {
                            ID = buffer.substring(start, end);
                        }

                        sqlDriver.createDictionaryWord("Wordlist", ID, Word, Dictionary);
                       // counter = counter + 1;
                        counter2 = counter2 + 1;

                    }

I need to make it work at least 5 times faster somehow. Thanks for any help.

Why wouldn't you use a XmlPullParser for this?

Michael Krause
– Michael Krause

2017-08-19 04:25:50 +00:00
Commented Aug 19, 2017 at 4:25 — Michael Krause
– Michael Krause, Commented Aug 19, 2017 at 4:25

Bob · Accepted Answer · 2017-08-19 04:36:55Z

1

Pattern matcher using regex is quite faster than indexOf() for longer Strings (For smaller Strings, indexOf() is better than regex). Use your text and a regex to find the index of your String pattern.

Pattern pattern = Pattern.compile(regex);

public static void getIndices(String text, Pattern pattern) {

    Matcher matcher = pattern.matcher(text);

    matcher.find();
    System.out.print("Start index: " + matcher.start());
    System.out.print("End index: " + matcher.end());

}

Note that you have to compile your regex to Pattern object only once for every regex and so don't put it inside a loop.

edited Aug 19, 2017 at 4:36

answered Aug 19, 2017 at 4:02

Bob

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2 Comments

Sapphire91140 Over a year ago

Count you please give me an example to get value between those two start = buffer.indexOf("<vocabulary>") + 12; end = buffer.indexOf("</vocabulary>"); I need value in between of that as string

Bob Over a year ago

Are you parsing an XML content? If so, as Michael as suggested in the comments, you should use XmlPullParser

Sapphire91140 · Accepted Answer · 2017-08-19 09:09:29Z

0

I made xml and used advice to use XmlPullParser. A bit faster, but still on some devices over minute, diring file size 1.7mb. Quite confusing.

answered Aug 19, 2017 at 9:09

Sapphire91140

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