Java URL encoding of query string parameters

Question

Say I have a URL

http://example.com/query?q=

and I have a query entered by the user such as:

random word £500 bank

Answer 1

Here's a method you can use in your code to convert a url string and map of parameters to a valid encoded url string containing the query parameters.

String addQueryStringToUrlString(String url, final Map parameters) throws UnsupportedEncodingException {
    if (parameters == null) {
        return url;
    }

    for (Map.Entry parameter : parameters.entrySet()) {

        final String encodedKey = URLEncoder.encode(parameter.getKey().toString(), "UTF-8");
        final String encodedValue = URLEncoder.encode(parameter.getValue().toString(), "UTF-8");

        if (!url.contains("?")) {
            url += "?" + encodedKey + "=" + encodedValue;
        } else {
            url += "&" + encodedKey + "=" + encodedValue;
        }
    }

    return url;
}