java.util.regex.Matcher is unable to find anything inside a String obtained from Apache IOUtils

I have a code snippet to convert an input stream into a String. I then use java.util.regex.Matcher to find something inside the string.

The following works for me:

StringBuilder sb = new StringBuilder();
InputStream ins; // the InputStream data
BufferedReader br = new BufferedReader(new InputStreamReader(ins));
br.lines().forEach(sb::append);
br.close();

String data = sb.toString();
Pattern pattern = Pattern.compile(".*My_PATTERN:(.*)");
Matcher matcher = pattern.matcher(data);
if (matcher.find())
   String searchedStr = matcher.group(1); // I find a match here

But if I try to replace BufferedReader with Apache IOUtils, I do not find any matches with the same string.

InputStream ins; // the InputStream data
String data = IOUtils.toString(inputStream, StandardCharsets.UTF_8);

Pattern pattern = Pattern.compile(".*My_PATTERN:(.*)");
Matcher matcher = pattern.matcher(data);
if (matcher.find())
   String searchedStr = matcher.group(1); // I cannot find a match here

I have tried with other "StandardCharsets" apart from UTF-8 but none have worked.

I am unable to understand what is different here that would cause IOUtils to not match. Can someone kindly help me out here?

Solution

The first code removes line brakes, the second doesn't.

So you should define multiline pattern matching:

In the pattern (starting with flags s=dotall, m=multiline)

Pattern pattern = Pattern.compile("(?sm).*My_PATTERN:(.*)");

In the pattern v2

Pattern pattern = Pattern.compile("[\\s\\S]*My_PATTERN:([\\s\\S]*)");

With flags

Pattern pattern = Pattern.compile(".*My_PATTERN:(.*)", MULTILINE|DOTALL);

All matches line brakes in the group's value.
Or remove line breaks ie:

data = data.replaceAll("\\r?\\n", "");

See: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html#compile(java.lang.String,%20int)

https://docs.oracle.com/javase/tutorial/essential/regex/pattern.html