Parse a URI String into Name-Value Collection

Question

I\'ve got the URI like this:

https://google.com.ua/oauth/authorize?client_id=SS&response_type=code&scope=N_FULL&access_type=offline&redirect_         


        

Answer 1

Java 8 one statement

Given the URL to analyse:

URL url = new URL("https://google.com.ua/oauth/authorize?client_id=SS&response_type=code&scope=N_FULL&access_type=offline&redirect_uri=http://localhost/Callback");

This solution collects a list of pairs:

List> list = 
        Pattern.compile("&").splitAsStream(url.getQuery())
        .map(s -> Arrays.copyOf(s.split("="), 2))
        .map(o -> new AbstractMap.SimpleEntry(decode(o[0]), decode(o[1])))
        .collect(toList());

This solution on the other hand collects a map (given that in a url there can be more parameters with same name but different values).

Map> list = 
        Pattern.compile("&").splitAsStream(url.getQuery())
        .map(s -> Arrays.copyOf(s.split("="), 2))
        .collect(groupingBy(s -> decode(s[0]), mapping(s -> decode(s[1]), toList())));

Both the solutions must use an utility function to properly decode the parameters.

private static String decode(final String encoded) {
    try {
        return encoded == null ? null : URLDecoder.decode(encoded, "UTF-8");
    } catch(final UnsupportedEncodingException e) {
        throw new RuntimeException("Impossible: UTF-8 is a required encoding", e);
    }
}