URLParamEncoder.java

package jeql.util;

public class URLParamEncoder {

  public static String encode(String input) {
      StringBuilder resultStr = new StringBuilder();
      for (char ch : input.toCharArray()) {
          if (isUnsafe(ch)) {
              resultStr.append('%');
              resultStr.append(toHex(ch / 16));
              resultStr.append(toHex(ch % 16));
          } else {
              resultStr.append(ch);
          }
      }
      return resultStr.toString();
  }

  private static char toHex(int ch) {
      return (char) (ch < 10 ? '0' + ch : 'A' + ch - 10);
  }

  private static boolean isUnsafe(char ch) {
      if (ch > 128 || ch < 0)
          return true;
      return " %$&+,/:;=?@<>#%".indexOf(ch) >= 0;
  }

}