Regex pattern matching

Question

Hello everyone I need a regex to replace everything inside de src= and /> tag on this line

src="../../../../../mailPhotos/assasins1.jpeg" alt="" width="284" height="177" /></p>

The code I'm trying for the regex is the following:

String regex="src=\"../../../../../ndeveloperDocuments/mailPhotos/assasins1.jpeg\" alt=\"\" width=\"284\" height=\"177\" /></p>";
regex=regex.replaceFirst("src./>", "src='cid:"+1001+"'");

But it's not replacing anything. What I though is that the regex would do something like "replace everything between src and />", but think I'm wrong as it doesn't work. What would be a regex to use in this case?.Thanks a lot

Answer 1

A . only matches a single character. To match any number of single characters, use .* (0 or more) or .+ (1 or more).

It's easy for this kind of matching to go wrong, however. For example, if you have a string like src="foo" /> Some other content <br /> your regex will match all the way to the final /> and swallow up tyhe other content. A common way to prevent this is to use a regex like src=[^>]+/>. The [^>] means "any character except >.

Answer 2

. only matches one character. To match zero or more characters, use .* and to match one or more characters use .+.

So, your code would be:

String regex="src=\"../../../../../ndeveloperDocuments/mailPhotos/assasins1.jpeg\" alt=\"\" width=\"284\" height=\"177\" /></p>";
regex=regex.replaceFirst("src.*/>", "src='cid:"+1001+"'");