HTTP Request Object

Question

Is there an object within the standard Java SE that can accept a HTTP request from a socket? I have found how to create and send one, however I have not found a way to retrieve a HTTP object from a socket. I can create one my self, but I would rather rely on a heavily tested object.

This seems like something that would be readily available given the structure of JSP.

Answer 1

It looks like you are looking for a Servlet. A servlet is an API that lets you receive and respond to an HTTP request.

Your servlet gets deployed in a container, which is basically the actual Web server that will take care of all the protocol complexities. (The most populare are Tomcat and Jetty)

Answer 2

There is a small HTTP server in the Java 6 SDK (not sure if it will be in the JRE or in non-Sun JVM's).

From http://www.java2s.com/Code/Java/JDK-6/LightweightHTTPServer.htm :

import java.io.IOException;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
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 HttpServerDemo {
  public static void main(String[] args) throws IOException {
    InetSocketAddress addr = new InetSocketAddress(8080);
    HttpServer server = HttpServer.create(addr, 0);

    server.createContext("/", new MyHandler());
    server.setExecutor(Executors.newCachedThreadPool());
    server.start();
    System.out.println("Server is listening on port 8080" );
  }
}

class MyHandler implements HttpHandler {
  public void handle(HttpExchange exchange) throws IOException {
    String requestMethod = exchange.getRequestMethod();
    if (requestMethod.equalsIgnoreCase("GET")) {
      Headers responseHeaders = exchange.getResponseHeaders();
      responseHeaders.set("Content-Type", "text/plain");
      exchange.sendResponseHeaders(200, 0);

      OutputStream responseBody = exchange.getResponseBody();
      Headers requestHeaders = exchange.getRequestHeaders();
      Set<String> keySet = requestHeaders.keySet();
      Iterator<String> iter = keySet.iterator();
      while (iter.hasNext()) {
        String key = iter.next();
        List values = requestHeaders.get(key);
        String s = key + " = " + values.toString() + "\n";
        responseBody.write(s.getBytes());
      }
      responseBody.close();
    }
  }
}

Answer 3

Yeah, you make a new HTTP Request object from what you accept on the socket. What you do after that is up to you, but it should probably involve an HTTP Response.

import java.io.*;
import java.net.*;
import java.util.*;

public final class WebServer {
    public static void main(String args[]) throws Exception {
        int PORT = 8080;
        ServerSocket listenSocket = new ServerSocket(PORT);
        while(true) {
            HttpRequest request = new HttpRequest(listenSocket.accept());
            Thread thread = new Thread(request);
            thread.start();
        }
    }
}

From: http://www.devhood.com/tutorials/tutorial%5Fdetails.aspx?tutorial%5Fid=396
There's some more work to be done in the tutorial, but it does look nice.