业精于勤荒于嬉,行成于思毁于随

  马上就要开始转到新的项目组，做一个全新的项目了，对于HTTP协议需要一定的了解，所以周末自己用Java写了一个简单的web服务器试试，只能实现简单的html文件浏览。

主要包括三个类:WebServer(监听浏览器请求),SocketThread(处理浏览器请求的进程),StringUtil(实现一些公共的操作),下面是三个类的代码.


----WebServer----
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

public class WebServer {
 
 public static void main(String[] argv) throws IOException {
  ServerSocket servSocket = new ServerSocket(StringUtil.LISTENING_PORT);
  try {
   while (true) {
    Socket socket = servSocket.accept();
    new SocketThread(socket).start();
   }
  } finally {
   servSocket.close();
  }
 }
}
---SocketThread------
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintStream;
import java.io.Writer;
import java.net.Socket;

public class SocketThread extends Thread {
 private Socket socket = null;

 public SocketThread(Socket s) {
  this.socket = s;
 }

 public void run() {
  try {
   if (socket == null) {
    throw new Exception("==>SOCKET为空<==");
   }
   BufferedReader reader = new BufferedReader(new InputStreamReader(
     socket.getInputStream()));
   String fileName = "";
   while (true) {
    String str = reader.readLine();
    if (str == null || str.length() <= 0) {
     break;
    }
    //System.out.println("===>"+str);
    if (StringUtil.isGetRequestInfo(str)) {
     fileName = StringUtil.getFileName(str);
     break;
    }
   }
   //System.out.println("===>客户机IP==>"+socket.getInetAddress().toString());
   //System.out.println("===>客户机端口==>"+socket.getPort());   
   /*
    BufferedWriter writer = new BufferedWriter(new
    OutputStreamWriter(socket.getOutputStream()));
    */
   PrintStream outputStream = new PrintStream(socket.getOutputStream());
   File file = new File(StringUtil.WEBPATH + fileName);
   if (file.exists()) { //如果文件存在
    StringUtil.sendHttpHead(outputStream, file);
    StringUtil.sendFile(outputStream, file);
    outputStream.flush();
   } else { //文件没找到，返回404页面
    StringUtil.send404Page(outputStream);
    outputStream.flush();
   }
  } catch (Exception e) {
   e.printStackTrace();
  } finally {
   try {
    socket.close();
   } catch (Exception e) {
   }
  }
 }

}



---StringUtil-----
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.PrintStream;

/**
 * @author xiaoliang
 */
public class StringUtil {

 // 服务器监听的端口
 public static final int LISTENING_PORT = 8080;

 // 服务器文件的位置
 public static final String WEBPATH = "E:";

 /**
  * 判断该字符串是不是浏览器发送过来的请求头信息
  * @param str
  * @return
  */
 public static boolean isGetRequestInfo(String str) {
  if (str == null || str.length() <= 0)
   return false;
  boolean isGetStr = true;
  if (str.indexOf("GET") != 0) {
   isGetStr = false;
  }
  if (str.indexOf("HTTP/") <= 0) {
   isGetStr = false;
  }
  return isGetStr;
 }

 /**
  * 获得请求信息中的文件名,默认为index.html
  *
  * @param str
  * @return
  */
 public static String getFileName(String str) {
  String fileName = "index.html", s;
  int httpIndex = str.lastIndexOf("HTTP/");
  s = str.substring(3, httpIndex);
  s = s.trim();
  if (s != null && s.length() > 0 && s.indexOf(".") > 0) {
   fileName = s;
  }
  return fileName;
 }

 /**
  * 发送文件到客户端
  *
  * @param out
  * @param file
  */
 public static void sendFile(PrintStream out, File file) {
  try {
   DataInputStream in = new DataInputStream(new FileInputStream(file));
   int length = (int) file.length();
   byte[] buffer = new byte[length];
   in.readFully(buffer);
   out.write(buffer, 0, length);
   in.close();
  } catch (Exception e) {
   e.printStackTrace();
  }
 }

 /**
  * 发送返回的头部信息
  * @param out
  */
 public static void sendHttpHead(PrintStream outputStream, File file) {
  try {
   outputStream.println("HTTP/1.0200OK");
   outputStream.println("Content_Type:text／htm1");
   outputStream.println("Content_Length:" + file.length());
   outputStream.println("Server:moon webserver 1.0");
   outputStream.println("");
  } catch (Exception e) {
   e.printStackTrace();
  }
 }

 /**
  * 返回404页面
  * @param out
  */
 public static void send404Page(PrintStream out) {
  try {
   out.println("HTTP ／1.0 404 no found");
   out.println("Content_type:text/html");
   out.println("");
   out.println("Error404:file not found!");
  } catch (Exception e) {
   e.printStackTrace();
  }
 }
 
 public static void main(String[] argv) {
  String str = "GET /11.html HTTP/1.1";
  str = StringUtil.getFileName(str);
  System.out.println("==>" + str + "<==");
  File file = new File(StringUtil.WEBPATH + str);
  if (file.exists()) {
   System.out.println("exists");
  } else {
   System.out.println("not exists");
  }
 }

}