Java Session驗證碼案例程式碼例項解析
阿新 • • 發佈:2020-06-28
案例
使用者輸入使用者名稱,密碼以及驗證碼。
如果使用者名稱和密碼輸入有誤,跳轉登入頁面,提示:使用者名稱或密碼錯誤
如果驗證碼輸入有誤,跳轉登入頁面,提示:驗證碼錯誤
如果全部輸入正確,則跳轉到主頁success.jsp,顯示:使用者名稱,歡迎您思路
在生成驗證碼的時候將它的值存入到session中,在比對的時候再取出來進行對比
程式碼index.jsp
<%-- Created by IntelliJ IDEA. User: tanglei Date: 2020/6/26 Time: 下午12:48 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>login</title> <script> window.onload = function(){ document.getElementById("img").onclick = function(){ this.src="/login_time_war_exploded/checkCode?time="+new Date().getTime(); } } </script> <style> div{ color: red; } </style> </head> <body> <form action="/login_time_war_exploded/login" method="post"> <table> <tr> <td>使用者名稱</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="/login_time_war_exploded/checkCode"></td> </tr> <tr> <td colspan="2"><input type="submit" value="登入"></td> </tr> </table> </form> <div><%=request.getAttribute("cc_error") == null ? "" : request.getAttribute("cc_error")%></div> <div><%=request.getAttribute("login_error") == null ? "" : request.getAttribute("login_error") %></div> </body> </html>
success.jsp
<%-- Created by IntelliJ IDEA. User: tanglei Date: 2020/6/26 Time: 下午6:27 To change this template use File | Settings | File Templates. --%> <%@ 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>
驗證碼checkCode.java
package cn.guizimo.servlet; import javax.imageio.ImageIO; 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.awt.*; import java.awt.image.BufferedImage; import java.io.IOException; import java.util.Random; @WebServlet("/checkCode") public class CheckCode extends HttpServlet { @Override protected void doPost(HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException { int width = 100; int height = 50; //建立圖片物件 BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_BGR); //美化 Graphics g = image.getGraphics(); //背景 g.setColor(Color.PINK); g.fillRect(0,width,height); //邊框 g.setColor(Color.BLUE); g.drawRect(0,width - 1,height - 1); String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; Random ran = new Random(); StringBuilder sb = new StringBuilder(); for (int i = 1; i <= 4; i++) { int index = ran.nextInt(str.length()); char ch = str.charAt(index); sb.append(ch); g.drawString(ch+"",width/5*i,height/2); } String checkCode_session = sb.toString(); //將驗證碼存入session req.getSession().setAttribute("checkCode_session",checkCode_session); //干擾線 g.setColor(Color.GREEN); 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); } //輸出圖片到瀏覽器 ImageIO.write(image,"jpg",resp.getOutputStream()); } @Override protected void doGet(HttpServletRequest req,IOException { this.doPost(req,resp); } }
login.java
package cn.guizimo.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("/login") public class Login extends HttpServlet { @Override protected void doPost(HttpServletRequest req,IOException { //1.設定request編碼 req.setCharacterEncoding("utf-8"); //2.獲取引數 String username = req.getParameter("username"); String password = req.getParameter("password"); String checkCode = req.getParameter("checkCode"); //3.先獲取生成的驗證碼 HttpSession session = req.getSession(); String checkCode_session = (String) session.getAttribute("checkCode_session"); //刪除session中儲存的驗證碼 //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 //判斷使用者名稱和密碼是否一致 if("zhangsan".equals(username) && "123".equals(password)){//需要呼叫UserDao查詢資料庫 //登入成功 //儲存資訊,使用者資訊 session.setAttribute("user",username); //重定向到success.jsp resp.sendRedirect(req.getContextPath()+"/success.jsp"); }else{ //登入失敗 //儲存提示資訊到request req.setAttribute("login_error","使用者名稱或密碼錯誤"); //轉發到登入頁面 req.getRequestDispatcher("/login.jsp").forward(req,resp); } }else{ //驗證碼不一致 //儲存提示資訊到request req.setAttribute("cc_error","驗證碼錯誤"); //轉發到登入頁面 req.getRequestDispatcher("/login.jsp").forward(req,resp); } } @Override protected void doGet(HttpServletRequest req,resp); } }
測試登入介面
驗證碼錯誤
使用者名稱密碼錯誤
登入成功
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