Character encoding in com.sun.net.httpserver

Question

I'm trying to write a mock HTTP server for unit tests, I'm using the com.sun.net.httpserver classes for that. I'm having problem with the encoding of the URL: the query parameters are ISO-8859-1 encoded, but the URI that is passed to the handler (via HttpExchange) is not. As I can't change the encoding of the original server, I was wondering if there was a way to tell the HttpServer which encoding to use when decoding the URL. Thanks in advance.

Here is a test program:

package test34;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLEncoder;
import java.util.logging.Level;
import java.util.logging.Logger;

public class Main {
    public static void main(String[] args) {
        try {
            MockServer mock = new MockServer();
            mock.start(8642);
            URL url = new URL("http://localhost:8642/?p="
                    + URLEncoder.encode("téléphone", "ISO-8859-1"));
            System.out.println(url);
            InputStream in = url.openStream();
            while (in.read() > 0) {
            }
            in.close();
            mock.stop();
            System.out.println(mock.getLastParams().get("p"));
        } catch (IOException ex) {
            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
        }
    }    
}

And here is the code of the mock server:

package test34;

import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.Writer;
import java.net.InetSocketAddress;
import java.net.URI;
import java.net.URLDecoder;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Executors;

import com.sun.net.httpserver.Headers;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;

public class MockServer {

    private HttpServer httpServer;
    private Map<String, String> params;

    public void start(int port) {
        if (httpServer == null) {
            try {
                InetSocketAddress addr = new InetSocketAddress(port);
                httpServer = HttpServer.create(addr, 0);
                httpServer.createContext("/", new HttpHandler() {
                    @Override
                    public void handle(HttpExchange exchange) throws IOException {
                        try {
                            handleRoot(exchange);
                        } catch (RuntimeException e) {
                            throw e;
                        } catch (IOException e) {
                            throw e;
                        }
                    }
                });
                httpServer.setExecutor(Executors.newFixedThreadPool(1));
                httpServer.start();
            } catch (IOException e) {
                throw new RuntimeException(e.getMessage());
            }
        }
    }

    public void stop() {
        if (httpServer != null) {
            httpServer.stop(10);
            httpServer = null;
        }
    }

    public Map<String, String> getLastParams() {
        Map<String, String> result = new HashMap<String, String>();
        if (params != null) {
            result.putAll(params);
        }
        return result;
    }

    private void handleRoot(HttpExchange exchange) throws IOException {
        URI uri = exchange.getRequestURI();
        params = parseQuery(uri.getQuery());
        Headers responseHeaders = exchange.getResponseHeaders();
        responseHeaders.set("Content-Type", "text/plain;charset=ISO-8859-1");
        exchange.sendResponseHeaders(200, 0);
        OutputStream stream = exchange.getResponseBody();
        try {
            Writer writer = new OutputStreamWriter(stream, "ISO-8859-1");
            try {
                PrintWriter out = new PrintWriter(writer);
                try {
                    out.println("OK");
                } finally {
                    out.close();
                }
            } finally {
                writer.close();
            }
        } finally {
            stream.close();
        }
    }

    private static Map<String, String> parseQuery(String qry)
            throws IOException {
        Map<String, String> result = new HashMap<String, String>();
        if (qry != null) {
            String defs[] = qry.split("[&]");
            for (String def : defs) {
                int ix = def.indexOf('=');
                if (ix < 0) {
                    result.put(def, "");
                } else {
                    String name = def.substring(0, ix);
                    String value = URLDecoder.decode(
                            def.substring(ix + 1), "ISO-8859-1");
                    result.put(name, value);
                }
            }
        }
        return result;
    }
}

Answer 1

The javadoc of HttpExchange.getQueryString() says it returns "undecoded query string of request URI, or null if the request URI doesn't have one."

If it's not decoded, and since http headers have to be in 7 bit ASCII (ietf.org/rfc/rfc2616.txt) , then you can decode later with URLDecoder.decode(... "ISO-8859-1");