Fake HTTP Server in Java

import java.util.StringTokenizer; //TODO kept for test only; public class Program { static String reqString = "GET / http/1.1"; /* *write your input string here ↑ */ public static void main(String[] args) { run(); } public static void out(String s) { System.out.println(s); } public static void run() { try { System.out.println("The Client 8.8.8.8" + ":80"+ " is connected"); String requestString = reqString; String headerLine = requestString; if (headerLine == null) return; StringTokenizer tokenizer = new StringTokenizer(headerLine); String httpMethod = tokenizer.nextToken(); String httpQueryString = tokenizer.nextToken(); System.out.println("The HTTP request string is ...."); System.out.println(reqString); // out(httpMethod ); if (httpMethod.equals("GET")) { if (httpQueryString.equals("/")) { /** return the home page */ homePage(); } else { showPage(httpQueryString.substring(httpQueryString.indexOf('/') + 1, httpQueryString.length())); } } else { sendResponse(404, "The Requested resource not found."); } } catch (Exception e) { System.out.println(e.toString()); e.printStackTrace(); } } /** * Method used to compose the response back to the client. * * @param statusCode * @param responseString * @throws Exception */ public static void sendResponse(int statusCode, String responseString) { String HTML_START = "Fake HTTP Server in Java"; String HTML_END = ""; String NEW_LINE = "\r\n"; String statusLine = null; String serverdetails = Headers.SERVER + ": Fake Server"; String contentLengthLine = null; String contentTypeLine = Headers.CONTENT_TYPE + ": text/html" + NEW_LINE; if (statusCode == 200) statusLine = Status.HTTP_200; else statusLine = Status.HTTP_404; statusLine += NEW_LINE; responseString = HTML_START + responseString + HTML_END; contentLengthLine = Headers.CONTENT_LENGTH + responseString.length() + NEW_LINE; out(statusLine); out(serverdetails); out(contentTypeLine); out(contentLengthLine); out(Headers.CONNECTION + ": close" + NEW_LINE); /** adding the new line between header and body */ out(NEW_LINE); out(responseString); } /** * Method used to compose the home page response to the client */ public static void homePage() throws Exception { StringBuffer responseBuffer = new StringBuffer(); responseBuffer.append("HTTPServer Home Page.

"); sendResponse(200, responseBuffer.toString()); out(responseBuffer.toString()); } public static void showPage(String s) { out("I/'ll show "+s +".html"); } /** * class used to store headers constants * */ private static class Headers { public static final String SERVER = "Server"; public static final String CONNECTION = "Connection"; public static final String CONTENT_LENGTH = "Content-Length"; public static final String CONTENT_TYPE = "Content-Type"; } /** * class used to store status line constants * */ private static class Status { public static final String HTTP_200 = "HTTP/1.1 200 OK"; public static final String HTTP_404 = "HTTP/1.1 404 Not Found"; } }

Fake server