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Java Session驗(yàn)證碼案例代碼實(shí)例解析

更新時(shí)間：2020年06月28日 10:51:37 作者：歸子莫

這篇文章主要介紹了Java Session驗(yàn)證碼案例代碼實(shí)例解析,文中通過(guò)示例代碼介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值,需要的朋友可以參考下

案例

用戶(hù)輸入用戶(hù)名，密碼以及驗(yàn)證碼。

如果用戶(hù)名和密碼輸入有誤，跳轉(zhuǎn)登錄頁(yè)面，提示:用戶(hù)名或密碼錯(cuò)誤

如果驗(yàn)證碼輸入有誤，跳轉(zhuǎn)登錄頁(yè)面，提示：驗(yàn)證碼錯(cuò)誤

如果全部輸入正確，則跳轉(zhuǎn)到主頁(yè)success.jsp，顯示：用戶(hù)名,歡迎您思路

在生成驗(yàn)證碼的時(shí)候?qū)⑺闹荡嫒氲絪ession中，在比對(duì)的時(shí)候再取出來(lái)進(jìn)行對(duì)比

代碼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>用戶(hù)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(yàn)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="登錄"></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(yàn)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;
    //創(chuàng)建圖片對(duì)象
    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, 0, width, height);
    //邊框
    g.setColor(Color.BLUE);
    g.drawRect(0, 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(yàn)證碼存入session
    req.getSession().setAttribute("checkCode_session",checkCode_session);

    //干擾線(xiàn)
    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, HttpServletResponse resp) throws ServletException, 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, HttpServletResponse resp) throws ServletException, IOException {
    //1.設(shè)置request編碼
    req.setCharacterEncoding("utf-8");
    //2.獲取參數(shù)
    String username = req.getParameter("username");
    String password = req.getParameter("password");
    String checkCode = req.getParameter("checkCode");
    //3.先獲取生成的驗(yàn)證碼
    HttpSession session = req.getSession();
    String checkCode_session = (String) session.getAttribute("checkCode_session");
    //刪除session中存儲(chǔ)的驗(yàn)證碼
    //session.removeAttribute("checkCode_session");
    //3.先判斷驗(yàn)證碼是否正確
    if(checkCode_session!= null && checkCode_session.equalsIgnoreCase(checkCode)){
      //忽略大小寫(xiě)比較
      //驗(yàn)證碼正確
      //判斷用戶(hù)名和密碼是否一致
      if("zhangsan".equals(username) && "123".equals(password)){//需要調(diào)用UserDao查詢(xún)數(shù)據(jù)庫(kù)
        //登錄成功
        //存儲(chǔ)信息，用戶(hù)信息
        session.setAttribute("user",username);
        //重定向到success.jsp
        resp.sendRedirect(req.getContextPath()+"/success.jsp");
      }else{
        //登錄失敗
        //存儲(chǔ)提示信息到request
        req.setAttribute("login_error","用戶(hù)名或密碼錯(cuò)誤");
        //轉(zhuǎn)發(fā)到登錄頁(yè)面
        req.getRequestDispatcher("/login.jsp").forward(req,resp);
      }


    }else{
      //驗(yàn)證碼不一致
      //存儲(chǔ)提示信息到request
      req.setAttribute("cc_error","驗(yàn)證碼錯(cuò)誤");
      //轉(zhuǎn)發(fā)到登錄頁(yè)面
      req.getRequestDispatcher("/login.jsp").forward(req,resp);

    }
  }

  @Override
  protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    this.doPost(req, resp);
  }
}

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