【实例】登录错误时显示错误界面 · JavaWeb学习

login.html ~~~ <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> </body> <center> <h2>用户登录</h2> <form action="login" method="get"> <p>账号: <input type="text" name="name" /></p> <p>密码: <input type="text" name="passWord" /></p> <input type="submit" value="登录" /> </form> </center> </html> ~~~ LoginError.jsp ~~~ <!DOCTYPE html> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> </body> <center> <h2>用户登录错误界面</h2> <div > <%=request.getAttribute("errorMessage")%> </div> </center> </html> ~~~ LoginServlet.java ~~~ package zyw.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 java.io.IOException; @WebServlet(name = "LoginServlet",urlPatterns = "/login") public class LoginServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String userName = "xiaoming"; String userPass = "123456"; String name = request.getParameter("name"); String passWord = request.getParameter("passWord"); if (!name.equals(userName)) { //账户不存在 request.setAttribute("errorMessage", "账户不存在"); request.getRequestDispatcher("/loginError.jsp").forward(request, response); } else if (!passWord.equals(userPass)) { //密码错误 request.setAttribute("errorMessage", "密码错误"); request.getRequestDispatcher("/loginError.jsp").forward(request, response); } } } ~~~ ![](https://box.kancloud.cn/bf767e2049a0b47f6ca2a9f58d37a3cf_1112x230.png)