Replace URL in text with href (in Java)

Question

I have to tranform url's entered in plain text into html hrefs and I want to find multiple urls.

This: Hi here is a link for you: http://www.google.com. Hope it works.

Will become: Hi here is a link for you: <a href='http://www.google.com'>http://www.google.com</a>. Hope it works.

Found this code:

public String transformURLIntoLinks(String text){
String urlValidationRegex = "(https?|ftp)://(www\\d?|[a-zA-Z0-9]+)?.[a-zA-Z0-9-]+(\\:|.)([a-zA-Z0-9.]+|(\\d+)?)([/?:].*)?";
Pattern p = Pattern.compile(urlValidationRegex);
Matcher m = p.matcher(text);
StringBuffer sb = new StringBuffer();
while(m.find()){
    String found =m.group(0); 
    m.appendReplacement(sb, "<a href='"+found+"'>"+found+"</a>"); 
}
m.appendTail(sb);
return sb.toString();
}

Posted here https://stackoverflow.com/a/17704902

And it works perfectly. For all urls properly prefixed with http. But I also want to find url's starting with just www.

Can anyone that knows his regex help me out?

Try to begin your regex with (?:(https?|ftp):\/\/)? and it will match with url starting with just www — thibsc
– thibsc, Commented Mar 22, 2018 at 10:22

janssen-dev · Accepted Answer · 2018-03-22 13:22:02Z

1

~~Make the (https?|ftp):// part optional. This is done by adding a question mark ?. So it will be ((https?|ftp)://)?~~

Use this RegEx:

\b((https?|ftp):\/\/)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[A-Za-z]{2,6}\b(\/[-a-zA-Z0-9@:%_\+.~#?&//=]*)*(?:\/|\b)

Escape Java escape character (\):

\\b((https?|ftp):\\/\\/)?[-a-zA-Z0-9@:%._\\+~#=]{2,256}\\.[A-Za-z]{2,6}\\b(\\/[-a-zA-Z0-9@:%_\\+.~#?&//=]*)*(?:\\/|\\b)

Examples

Example 1 (with protocol, in sentence)

Example 2 (without protocol, in sentence)

edited Mar 22, 2018 at 13:22

answered Mar 22, 2018 at 10:24

janssen-dev

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3 Comments

Anders Over a year ago

The text I am transforming is not only urls. Tried implementing your code but it turned everything in my text into hrefs This: Hi here's a link for you www.google.com Take care! Turned into:

<a href='Hi here's'>Hi here's</a><a href=' a link'> a link</a><a href=' for you'> for you</a><a href='www.google.com'>www.google.com</a><a href='Take care!'>Take care!</a>

janssen-dev Over a year ago

@Anders I've edited my answer. I did not know it should take a link from a sentence. It should now be working.

Anders Over a year ago

Work like a charm. Added some code that adds the protocol and it's all set. Thanks for your help!

Saver · Accepted Answer · 2018-03-22 10:27:22Z

0

Make the www optinnal by surrounding. You case try this:

  final String urlValidationRegex = "(https?|ftp)://(www\\d?)?(|[a-zA-Z0-9]+)?.[a-zA-Z0-9-]+(\\:|.)([a-zA-Z0-9.]+|(\\d+)?)([/?:].*)?"

answered Mar 22, 2018 at 10:27

Saver

525 bronze badges

1 Comment

janssen-dev Over a year ago

That is not what OP is asking for. He want's to be able to omit the protocol, not the subdomain.

janssen-dev · Accepted Answer · 2018-03-22 13:37:30Z

0

You could try the following pattern.

((https?|ftp)://)?(www\d?|[a-zA-Z0-9]+)?.[a-zA-Z0-9-]+(:|.)([a-zA-Z0-9.]+|(\d+)?)([/?:].*)?

The updated code will be

public String transformURLIntoLinks(String text){
String urlValidationRegex = "((https?|ftp)://)?(www\\d?|[a-zA-Z0-9]+)?.[a-zA-Z0-9-]+(\\:|.)([a-zA-Z0-9.]+|(\\d+)?)([/?:].*)?";
Pattern p = Pattern.compile(urlValidationRegex);
Matcher m = p.matcher(text);
StringBuffer sb = new StringBuffer();
while(m.find()){
    String found =m.group(0); 
    m.appendReplacement(sb, "<a href='"+found+"'>"+found+"</a>"); 
}
m.appendTail(sb);
return sb.toString();
}

edited Mar 22, 2018 at 13:37

janssen-dev

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answered Mar 22, 2018 at 10:30

Aingaran

14 bronze badges

2 Comments

janssen-dev Over a year ago

Why use (something|) when you can just do (something)??

Aingaran Over a year ago

Yes, Using a meta-character is always better. Updated the post, Thanks.

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