Jason S Jason S - 5 months ago 28
Java Question

Decoding URI query string in Java

I need to decode a URI that contains a query string; expected input/output behavior is something like the following:

abstract class URIParser
/** example input:
* something?alias=pos&FirstName=Foo+A%26B%3DC&LastName=Bar */
URIParser(String input) { ... }
/** should return "something" for the example input */
public String getPath();
/** should return a map
* {alias: "pos", FirstName: "Foo+A&B=C", LastName: "Bar"} */
public Map<String,String> getQuery();

I've tried using java.net.URI, but it seems to decode the query string so in the above example I'm left with "alias=pos&FirstName=Foo+A&B=C&LastName=Bar" so there is ambiguity whether a "&" is a query separator or is a character in a query component.

Edit: I just tried URI.getRawQuery() and it doesn't do the encoding, so I can split the query string with a
, but then what do I do? Javascript has decodeURIComponent, I can't seem to find the corresponding method in Java.

Any suggestions? I would prefer not to use any new libraries.

Answer Source

See class URLDecoder