时间：2022-11-10 09:22:14 | 栏目：JAVA代码 | 点击：次
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
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：
//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：
servlet 登陆逻辑代码
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
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 {
}
}