How to convert map to url query string?

Question

Do you know of any utility class/library, that can convert Map into URL-friendly query string?

Example:

I have a map:

\"param1\"=12,
\"param2         


        

Answer 1

I wanted to build on @eclipse's answer using java 8 mapping and reducing.

 protected String formatQueryParams(Map params) {
      return params.entrySet().stream()
          .map(p -> p.getKey() + "=" + p.getValue())
          .reduce((p1, p2) -> p1 + "&" + p2)
          .map(s -> "?" + s)
          .orElse("");
  }

The extra map operation takes the reduced string and puts a ? in front only if the string exists.