Servlet 学习笔记 Session的设置及应用

本篇博客介绍的是Session 的设置及应用的事例,这个事例用到了一个html的代码login.html和三个Servlet的程序login.do user.view
logout这三个分别是用户登录的时的判断，用户的session的记录以及用户的注销下面附上代码（重要的部分带有注释）
login.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>欢迎登录</title>
</head>
<body>
    <form action="login.do" method="post">
       用户名:<input type="text" name="user"><br/>
           密码:<input type="password" name="password"><br/>
          <input type="submit" value="提交">
    </form>
</body>
</html>

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         response.setContentType("text/html;charset=UTF-8");//设置字符
         PrintWriter out =response.getWriter();
         String user=request.getParameter("user");//取得用户姓名
         String password=request.getParameter("password");//取得用户密码
         if("wanglin".equals(user) &&"123456".equals(password))//判断
         {
             HttpSession session=request.getSession(true);//false 没有的话也不新建
             session.setAttribute("login", user);//添加login属性
             request.getRequestDispatcher("user.view").forward(request,response);//forward方法的运用
         }
         else
             response.sendRedirect("login.html");//重定向

    }

user

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         HttpSession session =request.getSession();//获得请求里面的session
           if(session.getAttribute("login")==null)
           {
               response.sendRedirect("login.html");
           }
           else
           {
               response.setContentType("text/html;charset=UTF-8");
               PrintWriter out=response.getWriter();
               String user=(String)session.getAttribute("login");//获得session 属性
               String id=session.getId();
               out.println(user+"已登录"+"ID"+"为:"+id);
               out.print("<a href='logout.view'>注销</a>");
           }


    }

logout

package xhxy;

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

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

/**
 * Servlet implementation class Logout
 */
@WebServlet("/logout.view")
public class Logout extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Logout() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
           HttpSession session=request.getSession();
           response.setContentType("text/html;charset=UTF-8");
           PrintWriter out =response.getWriter();
            String name=(String)session.getAttribute("login");
            out.println(name+"已注销");
            session.invalidate();


    }

}

-初心不负-

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Servlet 学习笔记 Session的设置及应用

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