TCP Server on embedded system

Hi...I've been working on a TCP Server for an embedded system (TINI board). It can serve basic webpages and some error codes (like 404). I need it to handle images too and I can't seem to get it working. Does anyone have any good tutorial links I can look at? I've been Googleing a lot and can't seem to find anything that works.

Here's my code if anyone wants to take a look. It's based on some example code designed for the TINI board that I've modified. Sorry for the length and thanks for any input.

Code:

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package realtimewebpage;
import java.io.*;
import java.net.*;

public class RealTimeWebPage implements Runnable {

  private ServerSocket server;
  private int readTimeout;
  private Thread serverThread;
  private volatile boolean runServer;

  /**
  * Main method that tests the class.
  */

  public static void main(String[] args) throws IOException {

    // The port clients will connect on.
    // Port 80 is the default for HTTP requests.
    int localPort = 80;

    // The timeout in milliseconds to wait for a request from a client
    // after connecting.
    int readTimeout = 5000;

    // Create a RealTimeWebPage object using localPort and readTimeout.
    RealTimeWebPage server = new RealTimeWebPage(localPort, readTimeout);

    while (true){

      // Endless loop that executes while waiting for connections.
      try {

        // The thread can spend most of its time sleeping.
        Thread.sleep(1000);
      } catch (InterruptedException e) {
        System.out.print("InterruptedException: ");
        System.out.println(e.getMessage() );
      }
    } // end while(true)
  } // end main

  /**
  * Creates a thread to handle connection requests.
  *
  * @param localPort the port to listen for connections on.
  * @param readTimeout the time in milliseconds to wait for bytes from a remote host.
  *
  * @throws IOException on error in opening the server socket.
  */
  public RealTimeWebPage(int localPort, int readTimeout) throws IOException {

    // Create a server socket on localPort.
    // The ServerSocket object creates a socket object on receiving a
    // communication request.
    server = new ServerSocket(localPort);
    System.out.println("The server is listening on port " + localPort + ".");

    // serverThread uses the passed readTimeout value.
    this.readTimeout = readTimeout;

    // Create a thread to handle connection requests.
    serverThread = new Thread(this);

    // A Daemon thread ends when no user (non-Daemon) threads are running.
    serverThread.setDaemon(true);

    // The start() method calls the thread's run() routine.
    serverThread.start();
  } // end RealTimeWebPage constructor

  /**
  * Provides a way to stop the server under program control.
  */
  public void stopServer() {

    // When runServer is false, the run method ends.
    runServer = false;
    try {

      // Close the socket, ignoring exceptions.
      server.close();
    } catch (IOException e) {
    }
  } // end stopServer

  /**
  * Main method for the thread.
  * Accepts connections and calls a routine to handle each connection.
  */
  public void run() {

    // runServer remains true until an exception or the stop method sets it false.
    runServer = true;

    while (runServer) {
      try {

        // Wait for and accept a connection request.
        Socket socket = server.accept();

        try {

          // Call a method to handle the connection
          handleConnection(socket);

        } catch (IOException e) {
          System.out.print("IOException: ");
          System.out.println(e.getMessage());
        } finally {

          // Close the socket to release resources.
          // Ignore exceptions.
          try {
            socket.close();
          } catch (IOException e) {
          }
        }
      } catch (IOException e) {

        // There was an error while accepting a new socket.
        // Stop the server thread.
        runServer = false;
      }
    } // end while(runServer);
  } // end run

  /**
  * Handles a single conection.
  *
  * @param socket the connected socket
  *
  * @throws IOException on error when communicating with the remote
  *        host.
  */
  private void handleConnection(Socket socket) throws IOException {

    System.out.println("Connected to " + socket);

    // Set the read timeout for waiting for data from the remote host.
    socket.setSoTimeout(readTimeout);

    // An InputStream object reads data from the remote host.
    InputStream in = socket.getInputStream();

    // A Printstream object writes to the remote host.
    PrintStream out = new PrintStream(socket.getOutputStream());

    try {

      // Call a method to process a received request, passing the input
      // and output stream objects to use in communicating with the remote host.
      processRequest(in, out);

      // checkError also flushes the output stream to send the data immediately.
      if (out.checkError()) {
        System.out.println("An error occurred while sending a web page.");
      } else {
        System.out.println("A response was sent.");
      }
    } catch (InterruptedIOException e) {
      System.out.print("InterruptedIOException: ");
      System.out.println(e.getMessage());
      System.out.print("The connection timed out after receiving no data for : ");
      System.out.print(readTimeout / 1000);
      System.out.println(" seconds.");
    }
  } // end handleConnection

  /**
  * Processes an HTTP request.
  *
  * @param in an InputStream object
  * @param out a PrintStream object
  *
  * @throws IOException if there was an error communicating with the remote
  *        host.
  */
  private void processRequest(InputStream in, PrintStream out)
      throws IOException {

    // Read the first four received bytes.
    int b1 = in.read();
    int b2 = in.read();
    int b3 = in.read();
    int b4 = in.read();

    // This server supports GET requests only.
    // GET must be upper case.
    // Find out if the received bytes = "GET "
    if (('G' == b1) && ('E' == b2) && ('T' == b3) && (' ' == b4)) {

      // If yes, read any following bytes and store them in a String buffer.
      // Stop reading on detecting a space, a new-line or line-feed character
      // ('\r', '\n'), or and end-of-file marker (-1).
      StringBuffer requestBuffer = new StringBuffer();
      int b = in.read();
      while ((b != -1) && (b != ' ') && (b != '\r') && (b != '\n')) {
        requestBuffer.append((char)b);
        b = in.read();
      }

      // Convert the StringBuffer to a String to enable examining its contents.
      String requestedPage = requestBuffer.toString();

      // The server returns its real-time web page on receiving a request for
      // the default page or for /index.html.
      String defaultPage = "/";
      String indexPage = "/index.html";
      requestedPage=".".concat(requestedPage);
      if(requestedPage.equals("./")){
          requestedPage="./index.html";
      }
      //String fixedPage;
      //requestedPage.getChars(1, 100, fixedPage, 0);

      File fresource = new File(requestedPage);
      if (fresource.exists() || requestedPage.equals(defaultPage)) {


        // Call a routine to return the real-time web page.
        sendWebPage(out, requestedPage);

      } else {

        // If the requested file doesn't match a supported file name,
        // return an error page with error code 404.
        sendErrorPage(out, "404 Not Found");
      }

    } else {

      // "GET " wasn't received.
      // If -1 was returned, the input stream is closed, so do nothing.
      // For any other received data, return an error page with error code 501.
      if ((b1 | b2 | b3 | b4) != -1) {
        sendErrorPage(out, "501 Not Implemented");
      }
    } // end  if ('G' == b1 || 'E' == b2 || 'T' == b3 || ' ' == b4)
  } // end processRequest

  /**
  * Sends the web page containing real-time data.
  *
  * @param out a PrintStream object
  *
  * @throws IOException if there was an error sending the page.
  */
  private void sendWebPage(PrintStream out, String Page) throws IOException {
    File fresource = new File(Page);
    FileInputStream IndexWebPage = new FileInputStream(fresource);

    // Send the response's start line and headers
    out.print("HTTP/1.0 200 OK\r\n"
              + "Content-Type: text/html\r\n"
              + "\r\n");
    if(fresource.exists()){
    byte [] http_byte= new byte[200];
    IndexWebPage.read(http_byte);


    out.write(http_byte);
    }else{
        out.print("File Not Found");
    }

  }

  /**
  * Sends an error page with the specified error message.
  *
  * @param out a PrintStream object
  * @param errorMessage the page's error message
  *
  * @throws IOException if there was an error sending the page.
  */
  private void sendErrorPage(PrintStream out, String errorMessage)
      throws IOException
  {
    // Send the response's start line and headers.
    out.print("HTTP/1.0 ");
    out.print(errorMessage);
    out.print("\r\n"
              + "Content-Type: text/html\r\n"
              + "\r\n");

    // Send the error message.
    out.print("<html>"
              + "<head><title>");
    out.print(errorMessage);
    out.print("</title></head>"
              + "<body>"
              + "<h1>");
    out.print(errorMessage);
    out.print("</h1>"
              + "</body>"
              + "</html>");
  } // end sendErrorPage

} // end RealTimeWebPage class

---

I've rewritten part of the above code in an attempt to clean it up and get it to do what I need.

Code:

---

package TCPServer;

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

/**
 * TCP server that receives a single byte, increments the value, and
 * sends the incremented value back.
 *
 * This file and other embedded Ethernet and Internet code and resources are
 * available from www.Lvr.com.
 *
 * @author Jan Axelson
 * @author Shawn Silverman
 */

public class TcpServer implements Runnable {

  private ServerSocket server;
  private int readTimeout;
  private Thread serverThread;
  private volatile boolean runServer;

  /**
  * Main method that tests the class.
  */
  public static void main(String[] args) throws IOException {

    // The port that clients will connect on.
    int localPort = 5551;

    // The timeout in milliseconds to wait for data from a client
    // after connecting.
    int readTimeout = 5000;

    // Create a TcpServer object using localPort and readTimeout.
    TcpServer myTcpServer = new TcpServer(localPort, readTimeout);

    while (true){

      // Endless loop that executes while waiting for connections.
      try {

        // The thread can spend most of its time sleeping.
        Thread.sleep(1000);
      } catch (InterruptedException e) {
        System.out.print("InterruptedException: ");
        System.out.println(e.getMessage() );
      }
    } // end while(true)
  } // end main()

  /**
  * Creates a thread to handle connection requests.
  *
  * @param localPort the port to listen for connections on.
  * @param readTimeout the time in milliseconds to wait for bytes from a remote host.
  * @throws IOException on error in opening the server socket.
  */
  public TcpServer(int localPort, int readTimeout) throws IOException {

    // Create a server socket on localPort.
    // The ServerSocket object creates a socket object on receiving a
    // communication request.
    server = new ServerSocket(localPort);

    // The serverThread thread uses the readTimeout value passed to this constuctor.
    this.readTimeout = readTimeout;

    // Create a thread to handle connection requests.
    serverThread = new Thread(this);

    // The thread is a Daemon thread, which ends when no user (non-Daemon)
    // threads are running.
    serverThread.setDaemon(true);

    // The start() method calls the thread's run() routine.
    serverThread.start();
  } // end TcpServer constructor

  /**
  * Stops the server.
  */
  public void stop() {

    // When runServer is false, the run method ends.
    runServer = false;

    try {
      // Close the socket. Do nothing on an exception.
      server.close();
    } catch (IOException e) {
    }
  } // end stop()

  /**
  * Main method for the thread.
  */
  public void run() {

    // runServer remains true until an exception or the stop() method sets it false.
    runServer = true;

    while (runServer) {
      try {
        // Wait for and accept a connection request.
        Socket socket = server.accept();

        try {
          // Call a method to handle the connection.
          handleConnection(socket);

        } catch (IOException e) {
          System.out.print("Error while working with socket: ");
          System.out.println(e.getMessage());
        } finally {

          // Close the socket to release resources.
          // Do nothing on an exception.
          try {
            socket.close();
          } catch (IOException e) {
          }
        }
      } catch (IOException e) {

        // There was an error while accepting a new socket.
        // Stop the server thread.
        runServer = false;
      }
    } // end while (runServer)
  } // end run()

  /**
  * Handles a single conection.
  *
  * @param socket a connected socket
  * @throws IOException on error when communicating with the remote
  *        host.
  */
  private void handleConnection(Socket socket) throws IOException {

    // Set the read timeout for waiting for data from the remote host.
    socket.setSoTimeout(readTimeout);

    // An InputStream object reads data from the remote host.
    InputStream in = socket.getInputStream();

    // An Outputstream object writes to the remote host.
    OutputStream out = socket.getOutputStream();

    try {

      // Try to read a byte from the remote host.
      int b = 0;
      while (in.available()==0)
      {
          b=0;
      }
      b=in.available();
      byte[] http_request = new byte[b];

      in.read(http_request);
      String info = new String (http_request);

      System.out.println("Received: ");
      System.out.print(info);
      if(info.substring(0, 3).equals("GET"))
      {
      System.out.println("Sent: ");
      byte[] response="HTTP/1.1 200 OK\r\n\r\n<HTML><BODY>SIMPLE WEB PAGE</BODY></HTML>".getBytes();
      out.write(response);
      String write = new String (response);
      System.out.println(write);
      }

      else
      {
          byte[] BadForm = "HTTP/1.1 400 Bad Request\r\n\r\n".getBytes();
          out.write(BadForm);
          String error = new String (BadForm);
          System.out.println(error);
      }
      out.flush();
        out.close();

    } catch (InterruptedIOException ex) {

      // The read attempt has timed out.
      System.out.print("The remote host sent no data within ");
      System.out.print(readTimeout / 1000);
      System.out.println(" seconds.");
    }
  } // end handleConnection()
} // end TcpServer class

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This one?
http://www.java2s.com/Code/Java/Tiny...HttpServer.htm

I did something like prototype for HTTP server,
only problem with images that you have recognize request for image from client,
and send image like html page.