Extract string between two strings in java

Question

Your pattern is fine. But you shouldn't be split()ting it away, you should find() it. Following code gives the output you are looking for:

String str = "ZZZZL <%= dsn %> AFFF <%= AFG %>";
Pattern pattern = Pattern.compile("<%=(.*?)%>", Pattern.DOTALL);
Matcher matcher = pattern.matcher(str);
while (matcher.find()) {
    System.out.println(matcher.group(1));
}

I have answered this question here: https://stackoverflow.com/a/38238785/1773972

Basically use

StringUtils.substringBetween(str, "<%=", "%>");

This requirs using "Apache commons lang" library: https://mvnrepository.com/artifact/org.apache.commons/commons-lang3/3.4

This library has a lot of useful methods for working with string, you will really benefit from exploring this library in other areas of your java code !!!

Jlordo approach covers specific situation. If you try to build an abstract method out of it, you can face a difficulty to check if 'textFrom' is before 'textTo'. Otherwise method can return a match for some other occurance of 'textFrom' in text.

Here is a ready-to-go abstract method that covers this disadvantage:

  /**
   * Get text between two strings. Passed limiting strings are not 
   * included into result.
   *
   * @param text     Text to search in.
   * @param textFrom Text to start cutting from (exclusive).
   * @param textTo   Text to stop cuutting at (exclusive).
   */
  public static String getBetweenStrings(
    String text,
    String textFrom,
    String textTo) {

    String result = "";

    // Cut the beginning of the text to not occasionally meet a      
    // 'textTo' value in it:
    result =
      text.substring(
        text.indexOf(textFrom) + textFrom.length(),
        text.length());

    // Cut the excessive ending of the text:
    result =
      result.substring(
        0,
        result.indexOf(textTo));

    return result;
  }

Your regex looks correct, but you're splitting with it instead of matching with it. You want something like this:

// Untested code
Matcher matcher = Pattern.compile("<%=(.*?)%>").matcher(str);
while (matcher.find()) {
    System.out.println(matcher.group());
}