SimpleHttpServer.java

SimpleHttpServer.java

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class SimpleHttpServer {

  public static void main(String[] args) throws Exception {
    int port = 80;
    ServerSocket serverSocket = new ServerSocket(port);
    System.out.println("Server listening on port: " + port);

    while (true) {
      Socket clientSocket = serverSocket.accept();
      System.out.println("New connection openned.");

      InputStream is = clientSocket.getInputStream();
      InputStreamReader isr = new InputStreamReader(is);
      BufferedReader in = new BufferedReader(isr);

      OutputStream os = clientSocket.getOutputStream();
      OutputStreamWriter osw = new OutputStreamWriter(os);
      BufferedWriter out = new BufferedWriter(osw);

      String s;

      int contentLength = 0;
      while ((s = in.readLine()) != null) {
        System.out.println(s);

        if (s.startsWith("Content-Length:")) {
          contentLength = Integer.parseInt(s.substring(16));
        }

        if (s.isEmpty()) {
          break;
        }
      }

      char[] buffer = new char[contentLength];
      in.read(buffer, 0, contentLength);
      System.out.println(new String(buffer));

      String body = "<p>response</p>";

      out.write("HTTP/1.0 200 OK\r\n");
      out.write("Content-Type: text/html\r\n");
      out.write(String.format("Content-Length: %d\r\n", body.length()));
      out.write("\r\n");
      out.write(body);

      System.out.println("Connection terminated.");
      out.close();
      in.close();
      clientSocket.close();
    }
  }
}