Session+JSP Demo

時間 2019-11-08

標籤 session+jsp session jsp demo 欄目網站開發简体版

原文原文鏈接

驗證碼案例: 

需求:
 1.訪問帶有驗證碼的登陸頁面login.js
 2.用戶輸入用戶名和密碼

若是用戶名和密碼錯誤,跳轉到登陸頁面,提示用戶名密碼錯誤
若是驗證碼有誤,跳轉到登陸頁面,提示驗證碼錯誤
若是所有輸入正確,則跳轉到success.jsp,顯示用戶名,歡迎您!


步驟:
 1.設置request的編碼
 2.獲取參數Map集合
 3.獲取驗證碼
 4.將用戶信息封裝到User對象
 5.判斷程序生成的驗證碼和用戶輸入的驗證碼是否一致,從session中獲取程序生成的驗證碼
      *一致
          在此判斷用戶名和密碼是否一致(查詢數據庫)
             正確:登陸成功,存儲數據,跳轉到頁面(重定向Session域)
             不正確:給提示信息,跳轉登陸頁面

     *不一致
          1.給用戶提示信息,驗證碼錯誤 request
          2.跳轉登陸頁面 轉發

LoginServlet

package com.infosys.session; 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 { request.setCharacterEncoding("utf-8"); String username = request.getParameter("username"); String password = request.getParameter("password"); String checkCode = request.getParameter("checkCode"); HttpSession session = request.getSession(); String checkCode_session = (String) session.getAttribute("checkCode_session"); if (checkCode_session.equalsIgnoreCase(checkCode)) { if ("zhangsan".equals(username) && "123".equals(password)) { session.setAttribute("user", username); response.sendRedirect(request.getContextPath() + "/success.jsp"); } else { request.setAttribute("login_error", "用戶名或密碼錯誤"); request.getRequestDispatcher("/login.jsp").forward(request, response); } } else { request.setAttribute("cc_error", "驗證碼錯誤"); request.getRequestDispatcher("/login.jsp").forward(request, response); } } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } }

CheckCodeServlet

package com.infosys.servlet; import javax.imageio.ImageIO; import javax.servlet.ServletException; import javax.servlet.ServletOutputStream; 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.awt.*; import java.awt.image.BufferedImage; import java.io.IOException; import java.util.Random; @WebServlet("/checkCodeServlet") public class CheckCodeServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { int width = 100; int height = 50; //1.建立一對象，在內存中圖片(驗證碼圖片對象)
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); //2.美化圖片 //2.1 填充背景色
        Graphics g = image.getGraphics();//畫筆對象
        g.setColor(Color.PINK);//設置畫筆顏色
        g.fillRect(0, 0, width, height); //2.2畫邊框
 g.setColor(Color.BLUE); g.drawRect(0, 0, width - 1, height - 1); String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghigklmnopqrstuvwxyz0123456789"; //生成隨機角標
        Random ran = new Random(); StringBuilder sb = new StringBuilder(); for (int i = 1; i <= 4; i++) { int index = ran.nextInt(str.length()); //獲取字符
            char ch = str.charAt(index);//隨機字符
 sb.append(ch); //2.3寫驗證碼
            g.drawString(ch + "", width / 5 * i, height / 2); } String checkCode_session = sb.toString(); request.getSession().setAttribute("checkCode_session", checkCode_session); //2.4畫干擾線
 g.setColor(Color.GREEN); //隨機生成座標點

        for (int i = 0; i < 10; i++) { int x1 = ran.nextInt(width); int x2 = ran.nextInt(width); int y1 = ran.nextInt(height); int y2 = ran.nextInt(height); g.drawLine(x1, y1, x2, y2); } //3.將圖片輸出到頁面展現
        ImageIO.write(image, "jpg", response.getOutputStream()); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } }

login.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
    <script> window.onload = function () { document.getElementById("img").onclick = function () { this.src = "/cookie/checkCodeServlet?time=" + new Date().getTime(); } } </script>
</head>

<body>
<form action="/cookie/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>

            <td colspan="2"><img src="/cookie/checkCodeServlet" id="img"/></td>
        </tr>
        <tr>
            <td colspan="2"><input type="submit" value="登陸"/></td>
        </tr>
    </table>
</form>


<div><%= request.getAttribute("cc_error")%>
</div>
<div><%= request.getAttribute("login_error")%>
</div>

</body>
</html>

success.jsphtml

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h1><%=request.getSession().getAttribute("user")%>,歡迎您</h1>
</body>
</html>

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