动态生成验证码+验证码的校验

原创已于 2022-11-02 17:03:51 修改 · 1.7k 阅读

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CC 4.0 BY-SA版权

文章标签：

#servlet #java #开发语言

于 2022-10-26 15:49:21 首次发布

该博客主要围绕Java Servlet开发，涉及页面生成验证码、用户登录校验功能。同时设置了额外的过滤器条件，确保其他资源只有在用户登录的情况下才可访问，体现了Java Servlet在Web开发中的应用。

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页面s

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
  <meta charset="utf-8"/>
  <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
  <meta name="viewport" content="width=device-width, initial-scale=1"/>
  <title>首页</title>

  <!-- 1. 导入CSS的全局样式 -->
  <link href="css/bootstrap.min.css" rel="stylesheet">
  <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
  <script src="js/jquery-2.1.0.min.js"></script>
  <!-- 3. 导入bootstrap的js文件 -->
  <script src="js/bootstrap.min.js"></script>
  <style>
    span{
      color: red;
    }
  </style>

</head>
<body>
<%--<div align="center">
  <a
          href="${pageContext.request.contextPath}/fingPage" style="text-decoration:none;font-size:33px">查询所有用户信息
  </a>
</div>--%>
<div class="container" style="width: 400px;">
  <h3 style="text-align: center;">管理员登录</h3>
  <form action="${pageContext.request.contextPath}/login" method="post">
    <div class="form-group">
      <label for="user">用户名：</label>
      <input type="text" name="username" class="form-control" id="user" placeholder="请输入用户名"/>
      <span id="message"></span>
    </div>

    <div class="form-group">
      <label for="password">密码：</label>
      <input type="password" name="password" class="form-control" id="password" placeholder="请输入密码"/>
      <span id="message1"></span>
    </div>

    <div class="form-inline">
      <label for="vcode">验证码：</label>
      <input type="text" name="verifycode" class="form-control" id="verifycode" placeholder="请输入验证码" style="width: 120px;"/>
      <img src="${pageContext.request.contextPath}/checkCode" title="看不清点击刷新" id="vcode"/><a id="a" href="javascript:refreshCode()">看不清？请点击</a>
    </div>
    <hr/>
    <div class="form-group" style="text-align: center;">
      <input class="btn btn btn-primary" type="submit" value="登录">
    </div>
  </form>

  <!-- 出错显示的信息框 -->
  <div class="alert alert-warning alert-dismissible" role="alert">
    <button type="button" class="close" data-dismiss="alert" >
      <span>&times;</span></button>
    <strong>${login_msg}</strong>
  </div>
</div>
</body>
<script>
  window.onload=function () {
    var image=document.getElementById("vcode");
    image.onclick=function () {
      //给图片设置时间戳
      var data=new Date().getTime();
      image.src="${pageContext.request.contextPath}/checkCode?"+data;
    }
    let a = document.getElementsByTagName("a")[0].onclick=function () {
      var data=new Date().getTime();
      image.src="${pageContext.request.contextPath}/checkCode?"+data;
    }
  }
  //用户名验证
    let username = document.getElementById("user");
    username.onblur=function () {
      var reg=/^[\u4e00-\u9fa5a-zA-Z0-9]+$/;
      let value = document.getElementById("user").value;
      let message = document.getElementById("message");
      if(reg.test(value)){
          message.innerHTML="";
      }else{
         message.innerHTML="用户名有误，请重新输入！";
      }
  }
  //密码验证
  let password = document.getElementById("password");
  password.onblur=function () {
      var reg=/^[0-9a-zA-Z]{2,}$/;
      let value = password.value;
      let message = document.getElementById("message1");
      if(reg.test(value)){
          message.innerHTML="";
      }else{
        message.innerHTML="密码错误，请您重新输入！"
      }
  }

</script>
</html>

生成验证码

package cn.itcast.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 java.awt.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

/**
 * 随机生成验证码
 */
@WebServlet("/checkCode")
public class CheckCode extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //定义图片的宽和高
        int width =80;
        int height=36;
        //1.定义画布
        BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_3BYTE_BGR);
        //2.美化图片
        Graphics graphics=image.getGraphics();
        //2.1给图片设置背景色
        graphics.setColor(Color.pink);
        graphics.fillRect(0,0,width,height);
        //2.2给边框设置颜色
        graphics.setColor(Color.black);
        graphics.drawRect(0,0,width-1,height-1);
        //2.3给图片设置字面字符
        graphics.setColor(Color.BLUE);
        String word="abcdefghijklmnopqrxtuvwszABCDEFGHIJKLMNOPKRXTUVWSZ0123456789";
        Random random=new Random();
        //用于存储验证码
        StringBuilder builder=new StringBuilder();
        for(int i= 1;i<5;i++){
            int index = random.nextInt(word.length());
            char newstr = word.charAt(index);
            builder.append(newstr);
            graphics.setFont(new Font("黑体",Font.BOLD,24));
            Font font = graphics.getFont();
            graphics.drawString(String.valueOf(newstr),width/5*i,height/2);
        }
        //用于验证码的校验
        String checkword = builder.toString();
        request.getSession().setAttribute("checkCode",checkword);
        //2.4给画布设置画线
        graphics.setColor(Color.green);
        for(int i=1;i<7;i++){
            int x = random.nextInt(width);
            int x2 = random.nextInt(width);
            int y=random.nextInt(height);
            int y2=random.nextInt(height);
            graphics.drawLine(x,y,x2,y2);
        }
        //3.将图片输出到页面
        ImageIO.write(image,"jpg",response.getOutputStream());
    }
}

用户登陆校验

package cn.itcast.Servlet;

import cn.itcast.domain.UserInfo;
import cn.itcast.service.Impl.UserServiceImpl;
import cn.itcast.service.UserService;

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;

/**
 * 用户登陆
 */
@WebServlet("/login")
public class login extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        //2.1获取用户填写验证码
        String verifycode = request.getParameter("verifycode");

        //3.验证码校验
        HttpSession session = request.getSession();
        String checkCode = (String) session.getAttribute("checkCode");
        session.removeAttribute("checkCode");//确保验证码一次性
        if(!checkCode.equalsIgnoreCase(verifycode)){
            //验证码不正确
            //提示信息
            request.setAttribute("login_msg","验证码错误！");
            //跳转登录页面
            request.getRequestDispatcher("/index.jsp").forward(request,response);

            return;
        }
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        UserService service=new UserServiceImpl();
        String contextPath = request.getContextPath();
        UserInfo user = service.findOne(username, password);
        if(user==null){
            request.getRequestDispatcher("/index.jsp").forward(request,response);
        }else {
            response.sendRedirect(contextPath+"/fingPage");
        }
        request.setAttribute("userInfo",user);

    }
}

（额外）过滤器条件：在其他资源在登陆的情况下才可以访问

package cn.itcast.Servlet;

import cn.itcast.Utils.PageUtils;
import cn.itcast.service.Impl.UserServiceImpl;
import cn.itcast.service.UserService;

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;
import java.util.Map;

/**
 * 条件的分页查询
 */
@WebServlet("/fingPage")
public class FingPage extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=utf-8");
        String currentPage = req.getParameter("currentPage");
        String number = req.getParameter("number");
        if (currentPage == null ||"".equals(currentPage)) {
            currentPage="1";
        }
        if(number==null || "".equals(number)){
            number="5";
        }
        int currentPages = Integer.parseInt(currentPage);
        if(currentPages<=0){
            currentPages=1;
        }
        //获取按条件查询的参数
        Map<String, String[]> condition = req.getParameterMap();

        int numbers=numbers = Integer.parseInt(number);
        UserService userService=new UserServiceImpl();
        PageUtils pageUtils = userService.paging(currentPages, numbers,condition);
        if(currentPages>pageUtils.getTotalPage()){
            currentPages=pageUtils.getCurrentPage()-1;
            pageUtils = userService.paging(currentPages, numbers,condition);
        }
        req.setAttribute("page",pageUtils);
        req.getRequestDispatcher("/Jsp/list.jsp").forward(req,resp);
    }
}