服务器之家:专注于服务器技术及软件下载分享
分类导航

PHP教程|ASP.NET教程|Java教程|ASP教程|编程技术|正则表达式|C/C++|IOS|C#|Swift|Android|VB|R语言|JavaScript|易语言|vb.net|

服务器之家 - 编程语言 - Java教程 - java web实现自动登录

java web实现自动登录

2021-11-19 14:14ITzhongzi Java教程

这篇文章主要为大家详细介绍了java web实现自动登录,文中示例代码介绍的非常详细,具有一定的参考价值,感兴趣的小伙伴们可以参考一下

本文实例为大家分享了java web实现自动登录的具体代码,供大家参考,具体内容如下

实现思路

1、在登录的 api 或 servlet中验证用户名密码
2、如果验证成功,则把该用户信息存在 服务器 的 session 缓存中,并把 可以表示该用户的 信息存在 cookie中返回。例如: 

?
1
2
3
4
5
6
7
//存储 session
  request.getSession().setAttribute("userBean", queryUser);
 Cookie cookie = new Cookie("auto_login", username + "#" + password);
// 创建 cookie
    cookie.setMaxAge(60*60*24*7);  //设置时间为 一周
    cookie.setPath(request.getContextPath());
    response.addCookie(cookie);

3、创建一个过滤器,拦截所有的用户请求
4、在该过滤器中做相应的逻辑处理,如下:

  • 获取 服务器 session 缓存中同名的session。例如: UserBean userBean = (UserBean) request.getSession().getAttribute("userBean");
  • 验证是否为空,不为空说明用户登陆之后没有关闭浏览器 ,直接让请求通过过滤器,并定位到相应界面
  • 如果session为空,说明用户 从上一次登陆后关闭过浏览器,则 获取 用户请求中的cookie,验证是否有我们定义的可以标识用户的特殊cookie。
  • 如果没有改cookie ,则直接返回登陆界面。
  • 如果有该cookie,则通过cookie中的信息查新到用户的信息,并跳转到用户想跳转的界面

核心代码示例

servlet 登陆逻辑代码

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
package com.wl.servlet;
 
import com.wl.dao.UserDao;
import com.wl.dao.daoImpl.UserDaoImpl;
import com.wl.domain.UserBean;
 
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.SQLException;
 
@WebServlet(name = "LoginServlet")
public class LoginServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
 
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 
        try {
            String username = request.getParameter("username");
            String password = request.getParameter("password");
            String autoLogin = request.getParameter("auto_login");
 
            System.out.println(username + " = " + password + "  " + autoLogin);
            UserBean userBean = new UserBean();
            userBean.setPassword(password);
            userBean.setUsername(username);
            UserDao userDao = new UserDaoImpl();
            UserBean queryUser = userDao.login(userBean);
            if(queryUser != null){
                if("on".equals(autoLogin)){
                    Cookie cookie = new Cookie("auto_login", username + "#" + password);
                    cookie.setMaxAge(60*60*24*7);
                    cookie.setPath(request.getContextPath());
                    response.addCookie(cookie);
                }
                request.getSession().setAttribute("userBean", queryUser);
                response.sendRedirect("index.jsp");
            }else {
                request.getSession().setAttribute("errorInfo", "用户名密码不正确");
                request.getRequestDispatcher("login.jsp").forward(request,response);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

filter 过滤器核心代码

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
package com.wl.filter;
 
import com.wl.dao.UserDao;
import com.wl.dao.daoImpl.UserDaoImpl;
import com.wl.domain.UserBean;
import util.CookieUtil;
 
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.sql.SQLException;
 
@WebFilter(filterName = "AutoLoginFilter")
public class AutoLoginFilter implements Filter {
    public void destroy() {
    }
 
    public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {
        HttpServletRequest request = (HttpServletRequest) req;
 
        UserBean userBean = (UserBean) request.getSession().getAttribute("userBean");
        if(userBean != null){
            chain.doFilter(req, resp);
        } else {
            Cookie[] cookies = request.getCookies();
            Cookie auto_login = CookieUtil.findCookie(cookies, "auto_login");
            if(auto_login == null) {
                chain.doFilter(req,resp);
            } else {
                String value = auto_login.getValue();
                String username = value.split("#")[0];
                String password = value.split("#")[1];
                UserBean user = new UserBean();
                user.setUsername(username);
                user.setPassword(password);
                UserDao dao = new UserDaoImpl();
                try {
                    UserBean login = dao.login(user);
                    request.getSession().setAttribute("userBean", login);
                } catch (SQLException e) {
                    e.printStackTrace();
                }
                chain.doFilter(req, resp);
            }
        }
        chain.doFilter(req, resp);
    }
    public void init(FilterConfig config) throws ServletException {
 
    }
}

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。

原文链接:https://blog.csdn.net/ITzhongzi/article/details/86677149

延伸 · 阅读

精彩推荐