package ex01.pyrmont;

import java.net.Socket;

import java.net.ServerSocket;

import java.net.InetAddress;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.IOException;

import java.io.File;

public class HttpServer {

  /** WEB_ROOT is the directory where our HTML and other files reside.

   *  For this package, WEB_ROOT is the "webroot" directory under the working

   *  directory.  工作目錄

   *  The working directory is the location in the file system

   *  from where the java command was invoked.

   */

//    D:\intelliJIDE_Project\tom4book\webroot

  public static final String WEB_ROOT =

    System.getProperty("user.dir") + File.separator  + "webroot";

  private static final String SHUTDOWN_COMMAND = "/SHUTDOWN";

  private boolean shutdown = false;

  public static void main(String[] args) {

    HttpServer server = new HttpServer();

    server.await();

  }

  public void await() {

    ServerSocket serverSocket = null;

    int port = 8080;

    try {

      serverSocket =  new ServerSocket(port, 1, InetAddress.getByName("127.0.0.1"));

    }

    catch (IOException e) {

      e.printStackTrace();

      System.exit(1);

    }

    while (!shutdown) {

      Socket socket = null;

      InputStream input = null;

      OutputStream output = null;

      try {

        socket = serverSocket.accept();

        input = socket.getInputStream();

        output = socket.getOutputStream();//socket進socket出

        Request request = new Request(input);

        request.parse();//解析url

        Response response = new Response(output);

        response.setRequest(request);

        response.sendStaticResource();  //从output输出

        socket.close();

        shutdown = request.getUri().equals(SHUTDOWN_COMMAND);

      }

      catch (Exception e) {

        e.printStackTrace();

        continue;

      }

    }

  }

}

package ex01.pyrmont;

import java.io.InputStream;

import java.io.IOException;

public class Request {

  private InputStream input;

  private String uri;

  public Request(InputStream input) {

    this.input = input;

  }

  public void parse() {

    StringBuffer request = new StringBuffer(2048);

    int i;

    byte[] buffer = new byte[2048];

    try {

      i = input.read(buffer);

    }

    catch (IOException e) {

      e.printStackTrace();

      i = -1;

    }

    for (int j=0; j<i; j++) {

      request.append((char) buffer[j]);

     /* GET /index.html HTTP/1.1

      Host: localhost:8080

      Connection: keep-alive

      Upgrade-Insecure-Requests: 1

      User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36

      Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*;q=0.8

      Accept-Encoding: gzip, deflate, br

      Accept-Language: zh-CN,zh;q=0.9*/

    }

    System.out.print(request.toString());

    uri = parseUri(request.toString());

  }

  private String parseUri(String requestString) {

    int index1, index2;

    index1 = requestString.indexOf(' ');

    if (index1 != -1) {

      index2 = requestString.indexOf(' ', index1 + 1);

      if (index2 > index1)

        return requestString.substring(index1 + 1, index2);

    }

    return null;

  }

  public String getUri() {

    return uri;

  }

}

package ex01.pyrmont;

import java.io.OutputStream;

import java.io.IOException;

import java.io.FileInputStream;

import java.io.File;

/*

  HTTP Response = Status-Line

    *(( general-header | response-header | entity-header ) CRLF)

    CRLF

    [ message-body ]

    Status-Line = HTTP-Version SP Status-Code SP Reason-Phrase CRLF

*/

public class Response {

  private static final int BUFFER_SIZE = 1024;

  Request request;

  OutputStream output;

  public Response(OutputStream output) {

    this.output = output;

  }

  public void setRequest(Request request) {

    this.request = request;

  }

  public void sendStaticResource() throws IOException {

    byte[] bytes = new byte[BUFFER_SIZE];

    FileInputStream fis = null;

    try {

      File file = new File(HttpServer.WEB_ROOT, request.getUri());

      if (file.exists()) {

        fis = new FileInputStream(file);

        int ch = fis.read(bytes, 0, BUFFER_SIZE);

        while (ch!=-1) {

          output.write(bytes, 0, ch);

          ch = fis.read(bytes, 0, BUFFER_SIZE);

        }

      }

      else {

        String errorMessage = "HTTP/1.1 404 File Not Found\r\n" +

          "Content-Type: text/html\r\n" +

          "Content-Length: 23\r\n" +

          "\r\n" +

          "<h1>File Not Found</h1>";

        output.write(errorMessage.getBytes());

      }

    }

    catch (Exception e) {

      System.out.println(e.toString() );

    }

    finally {

      if (fis!=null)

        fis.close();

    }

  }

}