Question

I have below message String. I want to replace all the image tag which contains the occurence of sequence i.e ?custId=1234 with new string cid:

 String message = "Need to process  image tag <img src=\"http://danny.oz.au/p/56214815-tripod.jpg?custId=1234\"/>";

This what i tried after going thru bit of regex tutorial which replaces all image tag occurence with cid:. I am not getting how to fit the
one more filter i.e ?custId=1234 in regex so that replace only those image tags that contains ?custId=1234

  message = message.replaceAll("\\<img.*?>", "cid:");

EDIT:- For example if
input is

  "Need to process  image tag <img src=\"http://danny.oz.au/p/56214815-tripod.jpg?custId=1234\"/>";

output should be
“Need to process image tag cid:”;

becoz input contains img tag and ?custId=1234 both

input is

     "Need to process  image tag <img src=\"http://danny.oz.au/p/56214815-tripod.jpg?custId=1235\"/>";

output should be

     "Need to process  image tag <img src=\"http://danny.oz.au/p/56214815-tripod.jpg?custId=1235\"/>";

becoz input does not contain ?custId=1234 both

Answer 1

Try this: –

message = message.replaceAll("<img.*?\\?custId=1234.*?>", "cid:");

For your given input string: –

"Need to process  image tag <img src=\"http://danny.oz.au/p/56214815-tripod.jpg?"
+ "custId=1234\"/>"

this will give you: –

"Need to process  image tag cid:"

Also for input: –

"Need to process  image tag <img src=\"http://danny.oz.au/p/56214815-tripod.jpg?custId=1235\"/>"

OUTPUT: –

"Need to process  image tag <img src=\"http://danny.oz.au/p/56214815-tripod.jpg?custId=1235\"/>"

Also, I would suggest you to take a look at Jsoup - Java HTML Parser, which you should use to parse your HTML. Regex is not a good idea to parse HTML. You can only parse a limited range of tags.

You can also use HTML Cleaner

---

UPDATE: –

If you want your dot (.) to match newline also, you can use PAttern.DOTALL flag. Alternativey, in case of String.replaceAll(), you can add a (?s) at the start of the pattern, which is equivalent to this flag.

From the Pattern.DOTALL – JavaDoc : –

Dotall mode can also be enabled via the embedded flag expression (?s).
(The s is a mnemonic for “single-line” mode, which is what this is
called in Perl.)

So, you can modify your pattern like this: –

message = message.replaceAll("(?s)<img.*?\\?custId=1234.*?>", "cid:");