public String loginIn(HttpServletRequest request, Model model){ //获取用户名与密码 String username = request.getParameter("username"); String password = request.getParameter("password"); String code=request.getParameter("captcha"); // String type=request.getParameter("type"); //判断验证码是否正确（验证码已经放入session） HttpSession session = request.getSession(); String realCode = (String)session.getAttribute("VerifyCode"); if (!realCode.toLowerCase().equals(code.toLowerCase())){ model.addAttribute("msg","验证码不正确"); return "login"; }else{ //验证码正确则判断用户名和密码 // if(type.equals("1")){//管理员信息 model.addAttribute("msg","12345"); //用户名和密码是否正确 Admin admin=adminService.queryUserByNameAndPassword(username,password); ReaderInfo readerInfo=readerService.queryUserInfoByNameAndPassword(username,password); if(admin!=null){//该用户不存在 session.setAttribute("user",admin); session.setAttribute("type","admin"); } else if (admin==null && readerInfo==null){ model.addAttribute("msg","用户名或密码错误"); return "login"; } else if(readerInfo!=null){ session.setAttribute("user",readerInfo); session.setAttribute("type","reader"); } return "index"; } }

基于request.getAttribute与request.getParameter的区别详解

在Java Servlet和JSP开发中，HttpServletRequest接口提供了两种主要的方法来获取客户端发送到服务器的数据：getAttribute()和getParameter()。它们虽然都用于获取请求中的数据，但有着本质的区别，下面将详细...

request.getParameter()取值为null的解决方法

在Web开发中，获取客户端传递给服务器的数据是一种常见需求，通常使用request.getParameter()方法从HttpServletRequest对象中获取表单数据或者URL参数。然而，在实际应用中，开发者有时会遇到request....

解释import javax.servlet.http.HttpServletRequest; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class UserController { @RequestMapping("/profile") public String login(HttpServletRequest request) { String username = request.getParameter("username"); // 存储到Session中 request.getSession().setAttribute("username", username); return "Logged in successfully!"; } @RequestMapping("/profile") public String profile(HttpServletRequest request) { // 从Session中获取属性 String username = (String) request.getSession().getAttribute("username"); return "Welcome, " + username + "!"; } @RequestMapping("/logout") public String logout(HttpServletRequest request) { // 从Session中移除属性 request.getSession().removeAttribute("username"); return "Logged out successfully!"; } }

在每个请求的方法中，都使用HttpServletRequest对象来获取请求参数和会话属性，并返回相应的响应字符串。在@RequestMapping注释下，定义了每个方法所映射到的HTTP请求路径。@RestController注释表示这个类是一个REST...

public String userLogin(@RequestParam("username") String username,@RequestParam("password") String password,@RequestParam("character") String character, HttpServletRequest request, HttpServletResponse response,HttpSession session) { //登录方法 String username=request.getParameter("username"); String password=request.getParameter("password"); String character=request.getParameter("character"); if (username.isEmpty()) { request.setAttribute("error","请输入用户名");return "register";} if (password.isEmpty()) { request.setAttribute("error","请输入密码");return "register";} if (character.isEmpty()) { request.setAttribute("error","请勾选身份");return "register";}

接下来，你使用了 username.isEmpty()、password.isEmpty() 和 character.isEmpty() 来判断用户名、密码和身份是否为空字符串，并通过 request.setAttribute() 方法将错误信息存储在request对象中，然后返回...

public String login() throws IOException { HttpServletRequest request = ServletActionContext.getRequest(); String username = request.getParameter("username"); String password = request.getParameter("password"); String role = request.getParameter("role"); User user = userDao.selectBean(" where username = '" + username+ "' and password= '" + password + "' and userlock=0"); if (user != null && role.equals(user.getRole()+"")) { HttpSession session = request.getSession(); session.setAttribute("user", user); this.setUrl("index"); return "redirect"; } else { HttpServletResponse response = ServletActionContext.getResponse(); response.setCharacterEncoding("gbk"); response.getWriter().print( "<script language=javascript>alert('用户名或者密码错误');window.location.href='index';</script>"); } return null; }解释此代码

该方法首先获取 HttpServletRequest 对象，然后从请求参数中获取用户名、密码和用户角色信息。接下来，通过 userDao 对象调用 selectBean 方法，查询数据库中是否存在该用户，并且该用户没有被锁定。如果查询到了该...

private void adminLogin(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String username = request.getParameter("username"); String password = request.getParameter("password"); User user = new User(username, password); HttpSession session = request.getSession(); boolean isSuccess = this.userService.adminLogin(user, session); if (isSuccess) { response.sendRedirect("admin/main.jsp"); } else { request.setAttribute("msg", "用户名、密码输入错误，或者您没有登录权限"); request.getRequestDispatcher("admin/login.jsp").forward(request, response); } }

具体来说，它首先通过 request 对象获取到用户提交的用户名和密码，然后创建一个 User 对象并将用户名和密码保存在其中。接着，它获取当前请求的 HttpSession 对象，并调用 UserService 中的 adminLogin() 方法来...

@RequestMapping("/admin") @Controller public class AdminController { @Autowired private AdminService adminService; ///8.登录 @RequestMapping("/login") @ResponseBody public String Login(HttpServletRequest request, HttpServletResponse response) throws IOException { String username=request.getParameter("username"); String password=request.getParameter("password"); Admin admin =adminService.login(username,password); if(admin == null){ return new Result(false,null,"登录失败，用户名或密码错误！").toString(); }else{ return new Result(true,admin,"登录成功！").toString(); } } ///首页数据 @RequestMapping("/index") @ResponseBody public String index(){ Map<String,Integer> admin =adminService.index(); if(admin == null){ return new Result(false,null,"登录失败，用户名或密码错误！").toString(); }else{ return new Result(true,admin,"登录成功！").toString(); } } }

login方法用于处理用户登录请求，首先从HttpServletRequest中获取用户名和密码，然后调用注入的AdminService进行登录验证。如果验证成功，则返回一个Result对象表示登录成功，否则返回一个Result对象表示登录失败。 ...

private void Login(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String username = request.getParameter("username"); String password = request.getParameter("password"); User user = new User(username, password); HttpSession session = request.getSession(); boolean isSuccess = this.userService.Login(user, session); if (isSuccess) { response.getWriter().print(isSuccess); } }

它首先从客户端请求中获取用户名和密码，然后创建一个 User 对象，并将其传递给 UserService 的 Login 方法进行验证。如果用户验证成功，Login 方法将在 HttpSession 中保存用户信息，并将 isSuccess 设置为 true。...

import jakarta.servlet.http.Cookie; import jakarta.servlet.http.HttpServlet; import jakarta.servlet.http.HttpServletRequest; import jakarta.servlet.http.HttpServletResponse; import javax.servlet.; import javax.servlet.http.; import javax.servlet.annotation.; import java.io.IOException; @WebServlet(name = "registerServlet", value = "/registerServlet") public class registerServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setHeader("Content-Type","text/html;charset=UTF-8");//设置浏览器编码为utf-8，防止出现中文乱码 //接收前端表单输入的用户名和密码 String username = request.getParameter("Username"); String userPassword = request.getParameter("UserPassword"); //创建cookie，并将上文接收的用户名和密码存入cookie中 Cookie cookie=new Cookie(userPassword,username); cookie.setMaxAge(6010);//设置cookie存活时间为10分钟 //发送cookie至客户端，并跳转至注册成功页面 response.addCookie(cookie); String massage="<meta http-equiv='refresh' content='3;url=/Cookie_war_exploded/Login.jsp'>三秒后跳转到登陆页面，如果没有跳转，请点击 跳转按钮";//实现三秒之后自动跳转功能。 request.setAttribute("massage",massage); request.getRequestDispatcher("/registerVictory.jsp").forward(request,response); } }

其中，@WebServlet 注解用于声明这是一个 Servlet 类，request.getParameter() 用于获取前端输入的参数，Cookie 用于创建和操作 Cookie，response.addCookie() 用于将 Cookie 发送至客户端，request....

@WebServlet("/loginUrl") public class LoginController extends HttpServlet { private static final long serialVersionUID = 1L; public LoginController() { super(); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub String username = request.getParameter("username"); String password = request.getParameter("password"); UserService userService = new UserService(); LoginHistoryService loginHistoryService = new LoginHistoryService(); User res = userService.loginCheck(username, password); if(res != null) { //登录成功 //添加记录 LoginHistory loginHistory = new LoginHistory(); loginHistory.setUserId(res.getUserId()); loginHistory.setIp(request.getRemoteAddr()); loginHistory.setCreateTime(new Date()); loginHistoryService.addLoginHistory(loginHistory); //跳转 request.getSession().setAttribute("loginUser", res); request.getRequestDispatcher("/mainUrl").forward(request, response); }else { //登录失败 request.setAttribute("msg", "登录失败，请检查用户名和密码是否正确！"); request.getRequestDispatcher("/WEB-INF/pages/error.jsp").forward(request, response); } } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }

它从HTTP请求参数中获取用户名和密码，然后使用UserService对象调用loginCheck方法进行登录验证。如果验证通过，它将记录登录历史并将登录用户添加到会话中，然后将请求重定向到主页面。否则，它将请求转发到一个...

翻译一下下面代码import javax.servlet.; import javax.servlet.http.; import java.util.; import java.io.; public class LoginHttpService extends HttpServlet { @Override public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String username = request.getParameter("username"); String password = request.getParameter("password"); HttpSession session = request.getSession(); if (username.equals("admin") && password.equals("123")) { System.out.println("Login Success"); session.setAttribute("username", username); session.setAttribute("password", password); request.getRequestDispatcher("/main").forward(request, response); } else { System.out.println("Login Fail"); if (username != null && !username.equals("")) { session.setAttribute("username", username); } else { session.setAttribute("username", null); } if (password != null && !password.equals("")) { session.setAttribute("password", password); } else { session.setAttribute("password", null); } request.getRequestDispatcher("/fail").forward(request, response); } } }

在 service() 方法中，首先获取了请求中的 username 和 password 参数。然后，获取 HttpSession 对象，用于保存用户的登录状态。接着，如果输入的用户名和密码都正确，就将其保存在 HttpSession 中，并通过 request....

public Result login(@RequestBody Map map, HttpServletResponse response, HttpServletRequest request) { String username == (String) map.get("username."); String password ==(String) map.get("password."); Admin admin = adminService.login(username., password.); if (admin != null) { //让原来的登录信息失效 Cookie[] cookies == request..getCookies(); if (cookies != null) { for (Cookie cookie : cookies) { cookie.setMaxAge(0); } }

在这段代码中，首先从参数 map 中获取用户名和密码，然后通过调用 adminService 的 login 方法来进行登录验证，如果验证成功则执行后续操作。接下来的操作是让原来的登录信息失效，具体实现是通过遍历当前请求中的...

package com.servlet; 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; import java.io.IOException; import java.util.Arrays; @WebServlet("/registServlet") public class RegistServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("utf-8"); response.setCharacterEncoding("utf-8"); //获得用户提交的数据 String username = request.getParameter("username"); String password1 = request.getParameter("password1"); String password2 = request.getParameter("password2"); String[] hobbies= request.getParameter("hobby"); if(password1.equals(password2)){ //把用户消息放进session中 HttpSession session = request.getSession(); session.setAttribute("username",username); session.setAttribute("password1",password1); session.setAttribute("hobby", Arrays.toString(hobbies)); response.sendRedirect("success.jsp"); }else { request.getSession().setAttribute("pwdFail","yes"); response.sendRedirect("register.jsp"); } } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } }完善下拉框反馈

您选择的爱好是：<%=request.getSession().getAttribute("hobby")%></div> 这样，当用户注册成功后，会跳转到success.jsp页面，并显示用户选择的爱好。如果用户注册失败，则会跳转回register.jsp页面，并提示密码不...

public class LoginServlet extends HttpServlet { @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //处理POST请求 String username = request.getParameter("username"); String password = request.getParameter("password"); boolean rememberMe = "on".equals(request.getParameter("remember-me")); try { if (username != null && !username.trim().isEmpty() && password != null && !password.trim().isEmpty()) { String hashedPasswd = hashPassword(password); if (authenticate(username, hashedPasswd)) { HttpSession session = request.getSession(); session.setAttribute("username", username); response.sendRedirect("mean1"); } else { response.sendRedirect("/login.html?error=1"); } } else { response.sendRedirect("/login.html?error=2"); } } catch (SQLException e) { throw new ServletException("Cannot connect to DB", e); } catch (NoSuchAlgorithmException e) { throw new ServletException("Cannot encrypt password", e); }如何修改代码，将其变为根据两个不同用户进入两个不同的页面代码

String username = request.getParameter("username"); String password = request.getParameter("password"); boolean rememberMe = "on".equals(request.getParameter("remember-me")); try { if (username !...

import java.io.IOException; import ja.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; @WebServlet("/login") public class LoginServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public LoginServlet() { super(); } /** * @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 { String username = request.getParameter("username"); String password = request.getParameter("password"); if ("admin".equals(username) && "admin".equals(password)) { response.sendRedirect("success.jsp"); } else { response.sendRedirect("fail.jsp"); } } }

在doPost方法中，首先通过request.getParameter方法获取了用户输入的用户名和密码，然后进行简单的验证，如果用户名和密码都为“admin”，则将用户重定向到success.jsp页面；否则将用户重定向到fail.jsp页面。需要...

public class LoginAction extends Action { public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) { try { response.setContentType("application/x-www-form-urlencoded; charset=UTF-8"); List userlist=null; Session s=HibernateSessionFactory.getSession(); Transaction t=s.beginTransaction(); String username=request.getParameter("username"); String password=request.getParameter("password"); String action=request.getParameter("action"); System.out.println("action="+action+"username="+username+"password="+password); SQLQuery query=s.createSQLQuery("select * from [users] where username='"+username+"'"); userlist=query.list(); String s1="";ss if(!userlist.isEmpty()) s1="res=true"; else s1="res=false"; System.out.println("json="+s1); response.getWriter().write(s1);这段代码实现的功能

这段代码实现的功能是处理用户登录请求，接收用户输入的用户名和密码，从数据库中查询匹配的用户信息，并返回一个布尔值表示登录是否成功。具体实现方式是使用Hibernate框架连接数据库，通过SQL语句查询匹配的用户...

@RestController public class AdminController { @Autowired private AdminService adminService; @RequestMapping(value = "/admin/login/status",method = RequestMethod.POST) public Object loginStatus(HttpServletRequest request, HttpSession session){ JSONObject jsonObject = new JSONObject(); String name = request.getParameter("name"); String password = request.getParameter("password"); boolean flag = adminService.verifyPassword(name,password); if (flag){ jsonObject.put(Consts.CODE,1); jsonObject.put(Consts.MSG,"登录成功"); session.setAttribute(Consts.NAME,name); return jsonObject; } jsonObject.put(Consts.CODE,0); jsonObject.put(Consts.MSG,"用户名或密码错误"); return jsonObject; } }这段代码什么意思

方法中使用了HttpServletRequest和HttpSession对象，前者用于获取请求中的参数，后者用于在服务器端存储会话数据。如果管理员的用户名和密码正确，则返回一个JSON对象，其中CODE为1表示成功，MSG为"登录成功"，并...

public class RegisterServlet extends HttpServlet { protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String username = req.getParameter("username"); String password = req.getParameter("password"); String password1 = req.getParameter("s_password"); String message = null; if (password1.equals(password)) { User user = new User(username, password); user.setUsername(username); user.setPassword(password); //写入数据库的方法 Don Don = new Don(); Don.insertIt(user); resp.sendRedirect(req.getContextPath() + "/login.jsp"); } else { message = "密码不一致！"; req.setAttribute("Message", message); req.getRequestDispatcher("/Message.jsp").forward(req, resp); } } }

它从请求参数中获取用户名、密码和确认密码，如果确认密码与密码相同，则将用户信息写入数据库，并将用户重定向到登录页面。如果确认密码与密码不同，则将错误信息存储在请求属性中，并通过转发将用户重定向到消息...

public R login(String username, String password, String captcha, HttpServletRequest request)

HttpServletRequest request 则是用于获取请求信息的对象，可以从中获取 ip 地址等信息进行登录验证。在方法中，首先会对用户名和密码进行验证，判断其是否合法。如果合法，再对验证码进行验证。如果验证码也合法...

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