I am trying to create a simple HttpServer in Java to handle GET requests, but when I try to get the GET parameters for a request I noticed the HttpExchange class does not have a method for that.
Does anybody know an easy way to read the GET parameters (query string)?
This is how my handler looks like:
public class TestHandler{
@Override
public void handle(HttpExchange exc) throws IOxception {
String response = "This is the reponse";
exc.sendResponseHeaders(200, response.length());
// need GET params here
OutputStream os = exc.getResponseBody();
os.write(response.getBytes());
os.close();
}
}
.. and the main method:
public static void main(String[] args) throws Exception{
// create server on port 8000
InetSocketAddress address = new InetSocketAddress(8000);
HttpServer server = new HttpServer.create(address, 0);
// bind handler
server.createContext("/highscore", new TestHandler());
server.setExecutor(null);
server.start();
}
The following: httpExchange.getRequestURI().getQuery()
will return string in format similar to this: "field1=value1&field2=value2&field3=value3..."
so you could simply parse string yourself, this is how function for parsing could look like:
import java.net.URLDecoder
public Map<String, String> queryToMap(String query) {
if (query == null) {
return null;
}
Map<String, String> result = new HashMap<>();
for (String param : query.split("&")) {
String[] entry = param.split("=");
if (entry.length > 1) {
result.put(
URLDecoder.decode(entry[0], "UTF_8"),
URLDecoder.decode(entry[1], "UTF_8")
);
} else {
result.put(
URLDecoder.decode(entry[0], "UTF_8"),
""
);
}
}
return result;
}
And this is how you could use it:
Map<String, String> params = queryToMap(httpExchange.getRequestURI().getQuery());
System.out.println("param A=" + params.get("A"));
Note: URLDecoder.decode
allows to manage special characters liek +
.