DouWs.java

package lol;

import java.io.IOException;
import java.net.InetSocketAddress;
import com.sun.net.httpserver.*;

public class DouWs {

    public static void main(String[] args) throws Exception {
        HttpServer server = HttpServer.create(new InetSocketAddress(8080), 0);
        server.createContext("/plus/", new MyDouHandler());
        server.setExecutor(null);
        server.start();
    }

    static class MyDouHandler implements HttpHandler {
        @Override
        public void handle(HttpExchange t) throws IOException {
            String uriPath = t.getRequestURI().toString().substring("/plus/".length());
            int sum = 0;

            for (String s: uriPath.split("/")){
                try {
                    sum += Integer.parseInt(s);
                } catch (NumberFormatException e){
                    String response = String.format("cannot parse number %s in the path %s: %s", s, uriPath, e.getMessage() );
                    t.sendResponseHeaders(400,response.length());
                    t.getResponseBody().write(response.getBytes());
                    t.getResponseBody().close();
                    return ;
                }
            }
            String response = String.format("%d", sum );
            t.sendResponseHeaders(299,response.length());
            t.getResponseBody().write(response.getBytes());
            t.getResponseBody().close();
        }
    }
}