title: Regular expression for excluding special characters
body: <p>I am having trouble coming up with a regular expression which would essentially black list certain special characters.</p>
  
  <p>I need to use this to validate data in input fields (in a Java Web app). We want to allow users to enter any digit, letter (we need to include accented characters, ex. French or German) and some special characters such as '-. etc. </p>
  
  <p>How do I blacklist characters such as &lt;>%$ etc?</p>