Servlet基础入门学习2

//1.在Servlet响应的时候进行添加Cookies,此时用户在收到响应头中会多一个set-Cookies字段; 
response.addCookie(new Cookie(name, value));

//2.设置Cookies后客户端再下一次请求的时候会将该请求带代入，我们可以用Servlet请求进行获取;
Cookie[] cook = request.getCookies();
//防止出现空指针
if(cook != null)
{
  for (Cookie cookie : cook) {
    response.getWriter().append(cookie.getName() + " ：" + cookie.getValue());
  }
}

//3.Cookies失效期设置一般关闭浏览器则数据消失负值，而如果是正值则按照其设置秒数进行设置失效时间
Cookie age = new Cookie("age", "18");
age.setMaxAge(60 * 60 * 24 * 7); //单位秒，正值时间过期，负值时间关闭浏览器即失效;
age.setMaxAge(0);  //删除Cookie


//4.设置新值（设置后任然需要进行提交）
age.setValue("2020");

//5.设置用于指定请求了指定的域名才会带上该Cookies
age.setDomain("127.0.0.1"); //只有在127.0.0.1该域才生效（可以区分内外网络）

//6.设置访问域名下的路径才会带有此Cookies
age.setPath("/");

//7.设置HttpOnly防止JS获取Cookies
age.setHttpOnly(true);

/**
 * Servlet 设置 Cookies 验证
 */
public class Demo1 extends HttpServlet {
  private static final long serialVersionUID = 1L;
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    response.setContentType("text/html; charset=UTF-8");
    //1.内容回显
    response.getWriter().append("Served at: ").append(request.getContextPath()+"<br/>");
    String name = request.getParameter("name");
    String value =request.getParameter("value");
    
    //2.设置Cookies和有效期默认是7天
    Cookie xm = new Cookie(name, value);
    xm.setMaxAge(60 * 60); // 失效时间 1个小时
    response.addCookie(xm);
    System.out.println("设置的Cookie1: " + name + " = " + value);
    
    //3.设置Cookies的有效期和HTTPOnly
    Cookie age = new Cookie("age", "18");
    age.setHttpOnly(true);
    age.setDomain("127.0.0.1");     //只有在127.0.0.1该域才生效（可以区分内外网络）
    age.setPath("/");  //设置域下访问的网页
    age.setMaxAge(60 * 60 * 24 * 7); //单位秒，正值时间过期，负值时间关闭浏览器即失效;
    age.setValue("2020");   //重新设置Cookie值
    response.addCookie(age);
    System.out.println("设置的Cookie2: " + age.getName() + " = " + age.getValue());

    //3.获取请求的Cookies
    Cookie[] cook = request.getCookies();
    //防止出现空指针
    if(cook != null)
    {
      for (Cookie cookie : cook) {
        String cn = cookie.getName();
        String cv = cookie.getValue();
        response.getWriter().append(cn + " ：" + cv + "<br>");
      }
    }
  
    //4.显示最近访问的时间是什么时候;
    if("name".equals(name) && "WeiyiGeek".equals(value))
    {
      System.out.println("用户登陆成功:"+ name);
      Cookie lastTime = until(cook,"lasttime"); //调用工具类进行查找
      //判断用户是否首测登陆过
      if(lastTime == null)
      {
        Cookie currentTime = new Cookie("lasttime",new Date().getTime()+"");
        currentTime.setMaxAge(60*60);
        response.addCookie(currentTime);
      }else {
        long lastVisitTime = Long.parseLong(lastTime.getValue()); //解析转换字符串为
        response.getWriter().append("<b>当前用户最近登陆时间:</b>"+new Date(lastVisitTime));
        lastTime.setValue(new Date().getTime()+"");        //重置用户登陆的时间
        response.addCookie(lastTime);  //修改后重新响应提交
      }
    }else{
      response.getWriter().append("<b>账号或者密码错误</b>");
    }
  }

  //5.工具类：搜素
  private Cookie until(Cookie[] userCook,String flag) {
    if(userCook != null) {
      for(Cookie ucook: userCook){
        if(flag.equals(ucook.getName())){
          return ucook;
        }
      }
    }
    return null;
  }


    //6.工具类，清除Cookies
    private Boolean clearCookie(Cookie cook)
    {
        cook.setvalue("");
        cook.setMaxAge(0);
        response.addCookie(cook);
    }

  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    doGet(request, response);
  }
}

//1.获取用户的Session会话ID
HttpSession session = request.getSession();
String sessionid = session.getId();
response.getWriter().append("<h5>用户当前Session会话ID值 :   " + sessionid + "</h5><br>");

//2.采用Session进行存值(在浏览器没有关闭后在没到失效时间时存放的值任然存在)
session.setAttribute("name", name);
session.setAttribute("pass", pass);

//3.获取Session中获取的值
session.getAttribute("name");
session.getAttribute("pass");

//4.移除值
session.removeAttribute("name");
session.removeAttribute("pass");

//5.关闭会话
session.invalidate();

<%@page import="java.util.Map"%>
<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Session</title>
</head>
<body>
<h1>Session 操作显示 </h1>
<p>
<!-- 简单的JSP定义说明 -->
<%! int a = 1234; %>
<% int b = 1024; %>
<b>a 值 = </b><%=a %> <br/>
<b>b 值 = </b><%=b %> <br/>
</p>

<!-- 登陆表单判断用户是否登录 -->
<!-- //3.获取会话设置的属性 -->
<% if (session.getAttribute("login") != "yes") { %>
<form action="Demo3" method="get">
  用户名称: <input type="text" name="name"><br>
  用户密码: <input type="password" name="pass"><br>
  <input type="submit" value="提交">
</form>
<% } else { %>
  <h4>尊敬的用户您已经成功登录了</h4> <p><a href="Demo3?action=logout">注销登陆</a></p>
  <p>请选择购买的商品：</p>
  <ol>
    <li><a href='Demo3?id=1'>安全数据</a></li>
    <li><a href='Demo3?id=2'>安全开发运维</a></li>
    <li><a href='Demo3?id=3'>DevOps</a></li>
    <li><a href='Demo3?id=4'>大型分布式网站架构</a></li>
    <li><a href='Demo3?id=5'>安全威胁分析</a></li>
  </ol>
  <hr>
  <p>您的购物车:<a href="#cart">go</a></p>
  <div>
    <table style="border: 1px black solid" cellspacing="1" cellpadding="1"  rules="all" align="center">
      <tr><th>商品名称</th> <th>购买数量</th></tr>
        <% //6.从Session中获取到map;
          Map<String,Integer> map = (Map<String, Integer>) session.getAttribute("cart");
          //遍历Map
          if (map != null)
          {
            for(String key: map.keySet()){
              int value = map.get(key);
              %>
              <tr> <td><%=key %></td> <td><%=value %> 本</td> </tr>
              <% 
            }
          }else{
            %>
              <tr> <td>暂无</td> <td>暂无</td> </tr>
            <%
          }
        %>
        
      </table>
  </div>
  <br>
  <p><a href="Demo3?action=del">清空购物车</a></p>
<% } %>
</body>
</html>

package top.weiyigeek.sesssion;
import java.io.IOException;
import java.util.LinkedHashMap;
import java.util.Map;

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

public class Demo3 extends HttpServlet {
  private static final long serialVersionUID = 1L;
    
  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    //0.获取JSP页面传递过来的参数
    String name = request.getParameter("name");
    String pass = request.getParameter("pass");
    String action = request.getParameter("action");
    String product = request.getParameter("id");
    String[] productname = {"安全数据", "安全开发运维", "DevOps","大型分布式网站架构" , "安全威胁分析"};
    
    // TODO Auto-generated method stub
    response.setContentType("text/html; charset=utf-8");
  
    if (name != null && pass != null ) {
      if("admin".equals(name) && "123456".equals(pass)) {
        //1.获取当前用户的Session会话值
        String sessionid = request.getSession().getId();
        response.getWriter().append("<br>用户登陆成功 <br>").append("当前 Session 会话值 : " + sessionid);
        
        //2.设置登陆会话属性
        request.getSession().setAttribute("login", "yes");
        response.getWriter().append("<br><a style='color:red' href='index.jsp'>浏览商品</p>");
        
      } else {
        response.getWriter().append("<p style='color:red'>账号或密码错误!</p>");
      }
    }
    
    //4.获取购物车存储的Session值
    
    if (product !=  null ) {
      int id = Integer.parseInt(product);
      String idname = productname[id-1];
      Map<String, Integer> map = (Map<String, Integer>) request.getSession().getAttribute("cart");
    
       //首次
      if(map == null) {
        //存入Map对象到Session
        map = new LinkedHashMap<String, Integer>();
        request.getSession().setAttribute("cart", map);
      }
    
      //判断是否存在该商品
      if(map.containsKey(idname)) {
        map.put(idname,map.get(idname)+1);
      }else {
        map.put(idname,1);
      }
      
      //界面跳转
      response.getWriter().append("<br><b>添加到购物车成功!</b>");
      response.getWriter().append("<p><a href='index.jsp'>返回商品页</a></p>");
      response.getWriter().append("<p><a href='index.jsp?#cart'>我的购物车</a></p>");

    }
    
    //7.清空购物车即session值与会话清除
    if ("del".equals(action)) {
      HttpSession session = request.getSession();
      session.removeAttribute("cart");
      response.sendRedirect("index.jsp");
    } else if ("logout".equals(action)) {
      //Session 会话清除
      request.getSession().invalidate();
      response.sendRedirect("index.jsp");
    }
  }

  
  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    doGet(request, response);
  }
}

<!--Developmentapache-tomcat-9.0.31confweb.xml -->
<!-- ==================== Default Session Configuration ================= -->
<!-- You can set the default session timeout (in minutes) for all newly   -->
<!-- created sessions by modifying the value below.                       -->
<session-config>
    <session-timeout>30</session-timeout>
</session-config>

$(document).ready(function(){
  $.ajax({url:"BaseServlet?method=UserVerity",async:true,success:function(result){ alert(result) }});
  $.post("BaseServlet",{"method":"Userverity","user":"tom"},function(data){alert(data)});
});

public class ServletDemo01 extends HttpServlet {
  private static final long serialVersionUID = 1L;
  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    doGet(request, response);
  }

  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    //获取客户端提交到服务端的method对应的值
    String md=request.getParameter("method");
    //定义变量,存放功能执行完毕之后要转发的路径
    String path=null;
    
    //通过判断md中不同的内容来决定本次功能
    if("addStu".equals(md)){
      path=addStu(request, response);
    }else if("delStu".equals(md)){
      path=delStu(request, response);
    }else if("checkStu".equals(md)){
      path=checkStu(request, response);
    }else if("".equals(md)){
      path="Index.html";
    }
    
    if(null!=path){
      //服务端的转发
      request.getRequestDispatcher(path).forward(request, response);
    }
  }

  protected String addStu(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    System.out.println("添加学生");
    return "/test.html";
    
  }
  protected String delStu(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    System.out.println("删除学生");
    return "/test.html";
    
  }
  protected String checkStu(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    System.out.println("检查学生");
    response.getWriter().println("DDDDDD");
    return null;
  }
}

/***
 * 
 * @author WeiyiGeek
 * @desc 工具类:自建一个Servlet基础类所有继承该类的Servlet都将执行重写后的Service方法
 */
public class BaseServlet extends HttpServlet {
    @SuppressWarnings("unused")
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("BaseServlet - 被继承的基础Servlet中的Service方法");
        //1.获取请求的操作的方法
        String method = req.getParameter("method");
        //2.定义转发路径
        String redirection = null;
        //3.获取当前的字节码对象
        Class<? extends BaseServlet> clazz = this.getClass(); //此时获取的实际上是继承者的class即 UserOper.class
        try {
            //4.采用反射reflect形式获取到clazz的方法并且进行调用传入的指定方法
            Method md = clazz.getMethod(method, HttpServletRequest.class, HttpServletResponse.class);
            if (null != md) 
              redirection = (String) md.invoke(this, req, resp);
            
            //5.当跳转路径不为空的时候返回的指定路径
            if (null != redirection)
              req.getRequestDispatcher(redirection).forward(req, resp);

        }catch (Exception e) {
            e.printStackTrace();
        }
    }    
}

public class UserOper extends BaseServlet {
  private static final long serialVersionUID = 1L;
       
    public UserOper() {
        super();
        System.out.println("UserOper Servlet 构造方法!");
    }

    //Servlet中对用户操作的方法
    public String addUser(HttpServletRequest request, HttpServletResponse reponse) throws ServletException {
        System.out.println("addUser - 添加用户!");
        return "Demo2/test.html";
    }
  
    public String showUser(HttpServletRequest request, HttpServletResponse reponse) throws ServletException {
        System.out.println("showUser - 查看用户!");
        return "Demo2/test.html";
    }       
}

UserOper Servlet 构造方法!
BaseServlet - 被继承的基础Servlet中的Service方法
addUser - 添加用户!

BaseServlet - 被继承的基础Servlet中的Service方法
showUser - 查看用户!