Use jsp to simply implement cookie page login, click remember and finally display the parameters on the form

Use jsp to simply implement cookie page login, and finally display the parameters on the form

First we should write our login interface

1. Username (text box)

2. Password (text box)

3. Remember me (button)

4. Login (button)

   demo1_login.jsp：

<form action="demo1_cookie.jsp" method="post">
   用户名:<input type="text" name="username" value="<%=username%>"/><br>
   密码: <input type="text" name="pwd" value="<%=pwd%>"/><br>
    <input type="radio" name="checkbox"> 记住我  <br>
    <input type="submit" name="提交">
</form>

Then on another jsp page demo1_cookie.jsp accept the parameters and save them to Cookie

1. First of all, we have to determine whether our remember me button is selected
2. New Cookie is given to username, we can set the duration of cookie here (because it needs to be installed* so write it)
3. new Cookie for pwd, we can also set the duration of the cookie here
4. Save our cookies

<%
    request.setCharacterEncoding("utf-8");
  //判断是否勾选了 "记住我"
    if (request.getParameter("checkbox")!=null){
        Cookie username = new Cookie("username",request.getParameter("username"));
        //保存一个小时
        username.setMaxAge(60*60);
        Cookie pwd = new Cookie("pwd",request.getParameter("pwd"));
        //保存一个小时
        pwd.setMaxAge(60*60);
        //保存cookie
        response.addCookie(username);
        response.addCookie(pwd);
    }

%>
<h1>登陆成功</h1>

Cookie cookie = new Cookie("","");

One party name, one value

String username = request.getParameter("username");
Cookie username = new Cookie("username",username);

So it’s abbreviated here because you want to install*

Cookie username = new Cookie("username",request.getParameter("username"));

This time we finished click remember me can save our cookie, no click cokkie will not save our cookie

How to be realistic in our form ? (Really confusing)

1. Traverse our cookies and get all our cookies

2. Get the name according to our getName method

3. Judging by name

4. When judging whether the value is empty

5. If you don't assign a value to null, it's done

demo1_login.jsp：

<%
String username="";  //用户名
String pwd="";       //密码
String c;            //接受值
    Cookie[] cookies = request.getCookies(); //拿到数据，才能遍历
    for (Cookie cookie : cookies) {
        
        c=cookie.getName(); //遍历 得到了所有cookie的参数

        if (c.equals("username")){
            //判断cookie的参数是否为空
            if (cookie.getValue()!=null){
                //赋值
                username=cookie.getValue();
                //控制台打印
                System.out.println(username);
            }
        }else if(c.equals("pwd")){
            //判断cookie的参数是否为空
            if (cookie.getValue()!=null){
                //赋值
                pwd=cookie.getValue();
                //控制台打印
                System.out.println(pwd);
            }
        }
    }
%>

Run screenshot:

First run:

After entering, click Remember me and submit

Log out and refresh to take a look at the form on our login page

Yahoo giao~~