java and regexp: how to match a string with lithreal parenthesis?

Question

I've this three text, and one regexp. (OK, it's HTML, but ...please, don't focus on it !!!!)

<h3 class="pubAdTitleBlock "><a href="/it/pubblicazioni/libri/Che-speranza-cè-per-i-morti/1101987030/" title="Che speranza c’è per i morti?">Che speranza c’è per i morti? (volantino N. 16)</a></h3>

<h3 class="pubAdTitleBlock "><a href="/it/pubblicazioni/libri/cosa-insegna-la-bibbia/È-questo-che-Dio-voleva/" title="È questo che Dio voleva?">Cosa insegna realmente la Bibbia?</a></h3>

<h3 class="pubAdTitleBlock">Cantiamo a Geova</h3>

This is the regexp

regexp = "<h3[^>]*>(<a[^>]*>)?([^<]+)(</a>)?</h3>";

I've three 3 groups:

• the opening <a> tag (optional)
• the text (it's a book title, it's the goal of regexp )
• the closing </a> tag (optional)

Problem : The second row is matched, the third is matched. The first no. Why ?

Matching code:

pattern = Pattern.compile(regexp);
matcher = pattern.matcher(fullString);
idx = 0;
while (matcher.find()) {
  ...
}

matcher.find() simply skips the first row. This is not the first row of the file, it's the 10th. It's the first of the example.

Can be the literal parenthesis the problem? how to fix the regexp ?

EDIT : I've tried

String regexp = "<h3[^>]*>(.+)</h3>";

But also this regexp skip the first row ... I really cannot understand !!!!

EDIT 2:

I'm having a dubt: can be a problem if there is the accented charcter ?

EDIT 3:

I'm trying to do data scraping from here: http://www.jw.org/it/pubblicazioni/libri/?contentLanguageFilter=it&sortBy=3

I've an input stream, then I convert to a single string using this code:

 // copied from http://stackoverflow.com/questions/309424/read-convert-an-inputstream-to-a-string
public static String convertStreamToString(InputStream is) {
    try {
        return new java.util.Scanner(is, "UTF-8").useDelimiter("\\A").next();
    } catch (java.util.NoSuchElementException e) {
        return "";
    }

Then I'm apllying the regexp ...

Answer 1

Not sure but maybe this is what you are looking for

String data = "<h3 class=\"pubAdTitleBlock \"><a href=\"/it/pubblicazioni/libri/Che-speranza-cè-per-i-morti/1101987030/\" title=\"Che speranza c’è per i morti?\">Che speranza c’è per i morti? (volantino N. 16)</a></h3>"
        + "<h3 class=\"pubAdTitleBlock \"><a href=\"/it/pubblicazioni/libri/cosa-insegna-la-bibbia/È-questo-che-Dio-voleva/\" title=\"È questo che Dio voleva?\">Cosa insegna realmente la Bibbia?</a></h3>"
        + "<h3 class=\"pubAdTitleBlock\">Cantiamo a Geova</h3>";

Pattern pattern = Pattern
        .compile("<h3[^>]*>(?:<a[^>]*>)?([^<]+)(?:</a>)?</h3>");
Matcher matcher = pattern.matcher(data);
while (matcher.find()) 
    System.out.println(matcher.group(1));

Output:

Che speranza c’è per i morti? (volantino N. 16)
Cosa insegna realmente la Bibbia?
Cantiamo a Geova

Little explanation:

groups like (?:someregex) will not be counted by regex mechanism. Thanks to that in (?:a)(b)(?:c)(d) group (b) will be indexed as 1 and (d) as 2.

Edit1

(I know its blasphemy to use regex to parse HTML but since OP wants it...)
You forgot to mention that parsed HTML contains white spaces like tabulations and new line marks inside <h3 > . Try it this way:

String data = convertStreamToString(new URL(
        "http://www.jw.org/it/pubblicazioni/libri/?contentLanguageFilter=it&sortBy=3")
        .openStream());

Pattern pattern = Pattern
        .compile("<h3[^>]*>\\s*(?:<a[^>]*>)?([^<]+)(?:</a>)\\s*?</h3>");
Matcher matcher = pattern.matcher(data);
int counter=0;
while (matcher.find())
    System.out.println(++counter +")"+matcher.group(1));

Output:

1)Accostiamoci a Geova
2)Accostiamoci a Geova — caratteri grandi
....
11)Cosa insegna realmente la Bibbia?
12)Cosa insegna realmente la Bibbia? — caratteri grandi

Answer 2

Don't do it with Parser or RegExp. Try Jerry . Like (not tested):

Jerry doc = jerry(html);
doc.$("a").each(new JerryFunction() {
    public boolean onNode(Jerry $this, int index) {
        String href = $this.attr("href");
        System.out.println(href);
    }
}

or any html-friendly query language. Because of non-externals requirements try Trying to parse links in an HTML directory listing using Java

(Copypasted my answer from: How do you parse links from html using Java? )

try 尝试

<h3.*?>(<a.*)?+(.*?)(</a>)?</h3>

and get group(2)

Just for the book title try: 只为书名尝试：

(.*>)?([^<]+?)<.*

your regexp 您的正则表达式

<h3[^>]*>(<a[^>]*>)?([^<]+)(</a>)?</h3>

looks to work for me.