title: What does %5B and %5D in POST requests stand for?
body: <p>I'm trying to write a Java class to log in to a certain website. The data sent in the POST request to log in is</p>
  <p><code>user%5Blogin%5D=username&amp;user%5Bpassword%5D=123456</code></p>
  <p>I'm curious what the <code>%5B</code> and <code>%5D</code> means in the key <strong>user login</strong>.</p>
  <p>How do I decode these data?</p>