通過使用標誌編譯 Pattern 來使用帶有自定義行為的正規表示式

可以使用標誌編譯 Pattern，如果正規表示式用作文字 String，則使用內聯修飾符：

Pattern pattern = Pattern.compile("foo.", Pattern.CASE_INSENSITIVE | Pattern.DOTALL);
pattern.matcher("FOO\n").matches(); // Is true.

/* Had the regex not been compiled case insensitively and singlelined,
 * it would fail because FOO does not match /foo/ and \n (newline)
 * does not match /./.
 */

Pattern anotherPattern = Pattern.compile("(?si)foo");
anotherPattern.matcher("FOO\n").matches(); // Is true.

"foOt".replaceAll("(?si)foo", "ca"); // Returns "cat".