title: Java Regex to match Vietnamese chars
body: <p>I have to write a regex to restrict a input field, that only allow Vietnamese chars, English chars and digits. I know how to restrict English chars (<code>[a-zA-Z]</code>) and digits (<code>[0-9]</code>), but don't know how to restrict Vietnamese chars.</p>
  
  <p>Can anyone give me a java regex to match Vietnamese chars?</p>
  
  <p>Vietnamese chars are Like: ể, ứ (Edit: but i don't know all of them. Otherwise, i can use<code>[a-list-of-chars]</code>, or maybe there is a range, like <code>[a-d]</code> instead of <code>[abcd]</code>)</p>