import java.net.*;  import java.nio.ByteBuffer;  import java.nio.channels.*;  import java.nio.charset.*;  import java.util.concurrent.*;  import java.io.*;    public class SimpleHttpServer {   private int port = 80;   private ServerSocketChannel serverSocketChannel = null;   private ExecutorService executorService;   private static final int POOL_MULTIPLE = 4;     public SimpleHttpServer() throws IOException {    executorService = Executors.newFixedThreadPool(Runtime.getRuntime()      .availableProcessors() * POOL_MULTIPLE);    serverSocketChannel = ServerSocketChannel.open();    serverSocketChannel.socket().setReuseAddress(true);    serverSocketChannel.socket().bind(new InetSocketAddress(port));   }     public void service() {    while (true) {     SocketChannel socketChannel = null;     try {      socketChannel = serverSocketChannel.accept();      executorService.execute(new Handler(socketChannel));     } catch (IOException e) {      e.printStackTrace();     }    }   }     public static void main(String[] args) throws IOException {    new SimpleHttpServer().service();   }    }    class Handler implements Runnable {   private SocketChannel socketChannel;   public Handler(SocketChannel socketChannel) {    this.socketChannel = socketChannel;   }     @Override   public void run() {    handle(socketChannel);   }     private void handle(SocketChannel socketChannel) {    try {     Socket socket = socketChannel.socket();     System.out       .println(socket.getInetAddress() + ":" + socket.getPort());     ByteBuffer buffer = ByteBuffer.allocate(1024);     socketChannel.read(buffer);     buffer.flip();     String request = decode(buffer);     StringBuffer sb = new StringBuffer("HTTP/1.1 200 OK\r\n");     sb.append("Content-Type:text/html\r\n\r\n");     socketChannel.write(encode(sb.toString()));     FileInputStream in = null;     String firstLineOfRequest = request.substring(0,       request.indexOf("\r\n"));     if (firstLineOfRequest.indexOf("login.htm") != -1)      in = new FileInputStream("login.htm");     else      in = new FileInputStream("hello.htm");     FileChannel fileChannel = in.getChannel();     fileChannel.transferTo(0, fileChannel.size(), socketChannel);    } catch (IOException e) {     e.printStackTrace();    } finally {     try {      if (socketChannel != null)       socketChannel.close();     } catch (IOException e) {      e.printStackTrace();     }    }   }     private Charset charset = Charset.forName("GBK");     private ByteBuffer encode(String string) {    return ByteBuffer.allocate(string.length() * 2).get(      string.getBytes(charset));   }     private String decode(ByteBuffer buffer) {    byte[] source = new byte[buffer.position() + 1];    buffer.put(source);    return new String(source, charset);   }  }