package com.lc.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class Ticketsell extends HttpServlet {


 public int ticket = 3;//假設只有三張票
 
 
 public void doGet(HttpServletRequest request, HttpServletResponse response)
  throws ServletException, IOException {
 PrintWriter out = response.getWriter();
 response.setContentType("text/html;charset=gbk");
 
 
 //簡單點而處理售票問題
 //當一個變量需要多個用戶共享，則應該在訪問該變量的時候加 同步機制
 //如果一個變量不需要共享則直接在doGet()和doPost()方法中定義即可,這樣的話就不存在線程的安全型問題
 
 
 synchronized (this) { //解決同步性問題的方法
  
  if(ticket > 0)
  {
  System.out.println("你買到票了！");
  out.println("你買到票了！");
  
  //休眠
  try {
   Thread.sleep(10*1000);
  } catch (InterruptedException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  ticket--;
  }
  else
  {
  System.out.println("你沒有買到票！");
  out.println("你沒有買到票！");
  }
 }
 
 }

 
 public void doPost(HttpServletRequest request, HttpServletResponse response)
  throws ServletException, IOException {
  
 this.doGet(request, response);

 }

}