【實例】登錄錯誤時顯示錯誤界面 · JavaWeb學習

login.html ~~~ <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> </head> <body> </body> <center> <h2>用戶登錄</h2> <form action="login" method="get"> <p>賬號: <input type="text" name="name" /></p> <p>密碼: <input type="text" name="passWord" /></p> <input type="submit" value="登錄" /> </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>用戶登錄錯誤界面</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)) { //賬戶不存在 request.setAttribute("errorMessage", "賬戶不存在"); request.getRequestDispatcher("/loginError.jsp").forward(request, response); } else if (!passWord.equals(userPass)) { //密碼錯誤 request.setAttribute("errorMessage", "密碼錯誤"); request.getRequestDispatcher("/loginError.jsp").forward(request, response); } } } ~~~ ![](https://box.kancloud.cn/bf767e2049a0b47f6ca2a9f58d37a3cf_1112x230.png)