jsp实现简单图片验证码功能
本文实例为大家分享了jsp实现简单图片验证码的具体代码,供大家参考,具体内容如下
一、实现的功能分析
(1)在登陆页面加验证码的功能,起到一定的安全性。在输入正确的验证码,用户名和密码的情况下,才可以实现登录。
(2)实现查询数据库的功能。在登陆后的页面中,显示用户名和密码,并且设置有一个超链接,实现查询数据库的功能。
(3)代码核心是:随机生成验证码,并且显示在页面上。同时要和输入框中的输入验证码进行校验。
(4)主页面使用img标签的src属性引入验证页面的jsp文件。
(5)验证码的实现页面使用BufferedImage类的方法产生图片。
(6)使用Graphics类的各种方法实现验证码的构成。
二、代码实现
(1)登录页面:index.jsp文件。
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>登录页面</title> </head> <body> <form action="LoginServlet" method="post"> 用户名:<input name="username" type="text" value=""/><br/><br/> 密码:<input name="password" type="password" value=""/><br/><br/> 验证码: <input type="text" name="checkCode" height="20px " value=""/> <img src="CodeServlet"/><span>${error_code}</span><br/> <input type="submit" value="提交"> </form> </body> </html>
(2)登录后的页面:user.jsp文件。
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <%@ page import = "com.entity.Author"%> <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>显示登录用户的用户名和密码页面</title> </head> <body> <% //内置对象 request.setCharacterEncoding("utf-8"); //获取交互层放入session中的obj Author obj = (Author)session.getAttribute("authorInfo"); if(obj != null){ out.print("<p>用户名:"+obj.getName()+"</p>"); out.print("<p>密码:"+obj.getId()+"</p>"); } else{ response.sendRedirect("index.jsp"); } %> <br/> <a href="AuthorServlet">用户信息查询 </a> </body> </html>
(3)实现数据查询页面:ueslist.jsp文件。
<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>查询信息显示页面</title> </head> <body> <table border="1"> <tr> <td>编号</td> <td>名称</td> <td>价格</td> <td>数量</td> <td>日期</td> <td>风格</td> </tr> <c:forEach items="${authorList}" var="author"> <tr> <td>${author.id}</td> <td>${author.name }</td> <td>${author.price }</td> <td>${author.num }</td> <td>${author.dates}</td> <td>${author.style}</td> </tr> </c:forEach> </table> </body> </html>
(4)定义一个Author类,用于接收数据库中的元素。
package com.entity; //用于获取数据库中的元素对象 public class Author { private int id; private String name; private int price ; private int num; private String dates; private String style; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getPrice() { return price; } public void setPrice(int price) { this.price = price; } public int getNum() { return num; } public void setNum(int num) { this.num = num; } public String getDates() { return dates; } public void setDates(String dates) { this.dates = dates; } public String getStyle() { return style; } public void setStyle(String style) { this.style = style; } }
(5)登录页面的交互层:LoginServlet.java文件。用于登录检验和验证码匹配。
//交互层(客户端和服务器的交互) package com.servlet; import java.io.IOException; import java.sql.SQLException; 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 com.dao.AuthorDao; import com.entity.Author; /** * Servlet implementation class LoginServlet */ @WebServlet("/LoginServlet") public class LoginServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public LoginServlet() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub //内置对象request,response request.setCharacterEncoding("utf-8"); HttpSession session = request.getSession(); //获取用户输入验证码 String checkCode = request.getParameter("checkCode"); //获取session中的验证码,也就是CodeServlet中生成的四个字符 String sessionCode = (String)session.getAttribute("sCode"); //验证码正确 if(checkCode.equals(sessionCode)) { //获取表单数据 String username = request.getParameter("username"); int password = Integer.valueOf(request.getParameter("password")); //判断用户信息是否正确,查询数据库获取用户信息 AuthorDao ad = new AuthorDao(); Author obj = ad.check(username, password); //判断 if(obj != null) { //重新放入用户信息 // HttpSession session = request.getSession(); session.setAttribute("authorInfo", obj); //设置session的有效期为10秒 session.setMaxInactiveInterval(10); //页面转发 response.sendRedirect("user.jsp"); } else { //页面重定向到登录页面 response.sendRedirect("index.jsp"); } } else { //验证码不正确 request.setAttribute("error_code", "验证码不匹配"); request.getRequestDispatcher("index.jsp").forward(request, response); } } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }
(6)数据库查询的交互层:AuthorServlet.java文件。
package com.servlet; import java.io.IOException; import java.util.List; 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 com.dao.AuthorDao; import com.entity.Author; /** * Servlet implementation class AuthorServlet */ @WebServlet("/AuthorServlet") public class AuthorServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public AuthorServlet() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub //设置编码方式 request.setCharacterEncoding("utf-8"); //查询用户列表 AuthorDao ad = new AuthorDao(); //将Dao层中的结果放入list中 List<Author> list = ad.queryAuthorList(); request.setAttribute("authorList", list); //请求转发的方式将查询结果放入request中,再将超链接直接访问AuthorServlet就将信息显示出来了。 request.getRequestDispatcher("uselist.jsp").forward(request, response); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }
(7)定义一个AuthorDao类实现查询数据库和检验登录的用户名和密码。
//用于检验登录页面所填入信息是否正确 package com.dao; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; import com.entity.Author; public class AuthorDao { public Author check(String username ,int password) { Author obj = null ; try { DBConnection db = new DBConnection(); //获取数据库连接 Connection conn = db.getConn(); //设置要执行的数据库语句 String sql = "select *from furnitures where name = ? and id = ?"; PreparedStatement ps = conn.prepareStatement(sql); //设置用户名和密码放入sql语句 ps.setString(1, username); ps.setInt(2, password); //执行sql查询语句 , 并将执行结果放入结果集中 ResultSet rs = ps.executeQuery(); //用户名和密码都正确 if(rs.next()) { //新创建一个obj 将查询结果放入 obj = new Author(); obj.setId(rs.getInt(1)); obj.setName(rs.getString(2)); obj.setPrice(rs.getInt(3)); obj.setNum(rs.getInt(4)); obj.setDates(rs.getString(5)); obj.setStyle(rs.getString(6)); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return obj; } public List<Author> queryAuthorList(){ Author obj = null; //定义一个list集合,用于存放查询结果 List<Author> list = new ArrayList<Author>() ; try { DBConnection db = new DBConnection(); //获取数据库连接 Connection conn = db.getConn(); //设置数据库要查询的语句 String sql = "select *from furnitures "; PreparedStatement ps = conn.prepareStatement(sql); //执行数据库查询语句,并将查询结果放入结果集 ResultSet rs = ps.executeQuery(); //利用循环将obj放入list集合中 while(rs.next()) { obj = new Author(); obj.setId(rs.getInt(1)); obj.setName(rs.getNString(2)); obj.setPrice(rs.getInt(3)); obj.setNum(rs.getInt(4)); obj.setDates(rs.getString(5)); obj.setStyle(rs.getString(6)); //将obj加入到list list.add(obj); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return list; } }
(8)定义一个验证码生成CodeServlet类,用于生成验证码。
package com.servlet; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.image.BufferedImage; import java.io.IOException; import java.util.Random; 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; @WebServlet("/CodeServlet") public class CodeServlet extends HttpServlet{ //定义验证码的源码 private static final String str ="abcdefghijklmnopqrstuvwxyaABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"; //定义随机数 private Random random = new Random(); //随机生成四个字符 public String getStr() { String s = ""; int len = str.length(); for(int i=0;i<4;i++) { s+=str.charAt(random.nextInt(len)); } return s; } //随机颜色 public Color getColor() { int red = random.nextInt(256); int green = random.nextInt(256); int blue = random.nextInt(256); Color color = new Color(red,green,blue); return color; } @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // TODO Auto-generated method stub //生成验证码图片 //画板 BufferedImage image = new BufferedImage(70,20,BufferedImage.TYPE_INT_RGB ); //画笔 Graphics pen = image.getGraphics(); //矩形 pen.fillRect(0, 0, 70, 20); //字体 pen.setFont(new Font("微软雅黑",Font.BOLD,20)); //获取4个字符 String code = getStr(); //绘制图片 for(int i=0;i<code.length();i++) { pen.setColor(getColor()); pen.drawString(String.valueOf(code.charAt(i)), i*15+5, 20);; } //response对象绘制图片到页面,Servle输出流进行图片的输出 ServletOutputStream sos = resp.getOutputStream(); ImageIO.write(image, "png", sos); sos.flush(); sos.close(); //验证码放入session HttpSession session = req.getSession(); session.setAttribute("sCode", code); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // TODO Auto-generated method stub doPost(req, resp); } }
(9)创建DBConnectoin.java类用户获取数据库连接。(我用的是mysql)
//获取数据库连接 package com.dao; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; public class DBConnection { private static String username="填入自己的数据库名"; private static String password="填入自己的数据库密码"; private static String driver = "com.mysql.jdbc.Driver"; private static String url="jdbc:mysql://localhost:3306/已经创建数据库名"; private Connection conn; static { try { //加载驱动,捕获异常 Class.forName(driver); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public DBConnection () throws SQLException { //连接数据库 conn = DriverManager.getConnection(url,username,password); } //用于获取conn public Connection getConn() { return conn; } public void setConn(Connection conn) { this.conn = conn; } }
三、页面
(1)登录页面
(2)数据查询页面
(3)查询结果显示页面
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。
相关文章
浅谈request.getinputstream只能读取一次的问题
下面小编就为大家带来一篇浅谈request.getinputstream只能读取一次的问题。小编觉得挺不错的,现在就分享给大家,也给大家做个参考。一起跟随小编过来看看吧2017-03-03浅谈SpringMVC jsp前台获取参数的方式 EL表达式
下面小编就为大家分享一篇浅谈SpringMVC jsp前台获取参数的方式 EL表达式,具有很好的参考价值,希望对大家有所帮助。一起跟随小编过来看看吧2018-03-03
最新评论