<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>老騷</title>
<script>
window.onload=function () {
document.getElementById("img").onclick=function () {
this.src="https://bbs.csdn.net/day16/checkCodeServlet?time="+new Date().getTime();
}
}
</script>
<style>
div{
color: red;
}
</style>
</head>
<body>
<from action="/day16/loginServlet" method="post">
<table>
<tr>
<td>用戶名</td>
<td><input type="text" name="username"></td>
</tr>
<tr>
<td>密碼</td>
<td><input type="password" name="password"></td>
</tr>
<tr>
<td>驗證碼</td>
<td><input type="text" name="checkCode"></td>
</tr>
<tr>
<td colspan="2"><img id="img" src="https://bbs.csdn.net/day16/checkCodeServlet"></td>
</tr>
<tr>
<td colspan="2"><input type="submit" value="https://bbs.csdn.net/topics/登錄" ></td>
</tr>
</table>
</from>
<%--
如果驗證碼錯誤或者用戶名密碼錯誤，login.jsp需要判斷是什么錯誤并輸出提示資訊
這里可以使用JSP腳本<%=%>來輸出提示
--%>
<div>
<%--
判斷Request域的“login_error”屬性是否為空，不為空列印它，下面的cc_error相同。為空就列印""這樣便不會顯示多余的資訊
JSP輸出腳本不能寫if-else，我們可以使用三元運算子?:來判斷
--%>
<%= request.getAttribute("login_error") == null? "" : request.getAttribute("login_error")%>
</div>
<div>
<%= request.getAttribute("cc_error") == null? "" : request.getAttribute("cc_error")%>
</div>
</body>
</html>
package cn.itcast.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;
@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.設定request編碼
request.setCharacterEncoding("utf-8");
response.setContentType("text/html");
//2.獲取引數
String username = request.getParameter("username");
String password = request.getParameter("password");
String checkCode = request.getParameter("checkCode");
//2.1先獲取生成的驗證碼
HttpSession session = request.getSession();
String checkCode_session = (String) session.getAttribute("checkCode_session");
session.removeAttribute("checkCode_session");
//3.先判斷驗證碼是否正確
if (checkCode_session!=null&&checkCode_session.equalsIgnoreCase(checkCode)) {
//忽略大小寫比較
//驗證碼正確
//判斷用戶名和密碼是否一致
if ("123".equals(username) && "123".equals(password)) {//需要呼叫UserDao查詢資料庫
//登錄成功
//存盤用戶資訊
session.setAttribute("user", username);
//重定向到success.jsp
response.sendRedirect(request.getContextPath() + "/success.jsp");
} else {
//登錄失敗
//存盤提示資訊到request
request.setAttribute("login_error", "用戶名或者密碼錯誤");
//轉發到登錄頁面
request.getRequestDispatcher("/login.jsp").forward(request, response);
}
} else {
//驗證碼不一致
//存盤提示資訊到request
request.setAttribute("cc_error", "驗證碼錯誤");
//轉發到登錄頁面
request.getRequestDispatcher("/login.jsp").forward(request, response);
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
}
uj5u.com熱心網友回復：
看看是不是form表單是action或者再看@webServket(" ")的路徑問題uj5u.com熱心網友回復：
在servlet輸出一下，看是否呼叫了servlet的方法uj5u.com熱心網友回復：
是沒輸出，不過重新建了個專案就好了轉載請註明出處，本文鏈接：https://www.uj5u.com/houduan/94586.html
標籤：Web 開發