Java tutorial
//package com.java2s; import java.util.BitSet; public class Main { static BitSet dontNeedEncoding; public static final boolean isURLEncoded(String str) { if (str == null || "".equals(str)) { return false; } char[] chars = str.toCharArray(); boolean containsPercent = false; for (char c : chars) { if (Character.isWhitespace(c)) { return false; } if (!dontNeedEncoding.get(c)) { return false; } if (c == '%') { containsPercent = true; } } if (!containsPercent) { return false; } return true; } }