jsp实现简单图片验证码功能

更新时间:2023-04-04 23:33:43 阅读：评论：0

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; chart=utf-8"  pageencoding="utf-8"%><!doctype html><html><head><meta chart="utf-8"><title>登录页面</title></head><body><form action="loginrvlet" method="post">   用户名：<input name="urname" 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="codervlet"/><span>${error_code}</span><br/>   <input type="submit" value="提交"></form></body></html>

（2）登录后的页面：ur.jsp文件。

<%@ page language="java" contenttype="text/html; chart=utf-8"  pageencoding="utf-8"%><%@ page import = "com.entity.author"%><!doctype html><html><head><meta chart="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.tcharacterencoding("utf-8");  //获取交互层放入ssion中的obj  author obj = (author)ssion.getattribute("authorinfo");   if(obj != null){   out.print("<p>用户名："+obj.getname()+"</p>");   out.print("<p>密码："+obj.getid()+"</p>");  }  el{   respon.ndredirect("index.jsp");  }%><br/><a href="authorrvlet">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; chart=utf-8"  pageencoding="utf-8"%><%@ taglib prefix="c" uri="/d/file/titlepic/" %><!doctype html><html><head><meta chart="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>${author.num }</td>  <td>${auth双高计划or.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 tid(int id) {  this.id = id; } public string getname() {  return name; } public void 奔腾电器广告tname(string name) {  this.name = name; } public int getprice() {  return price; } public void tprice(int price) {  this.price = price; } public int getnum() {  return num; } public void tnum(int num) {  this.num = num; } public string getdates() {  return dates; } public void tdates(string dates) {  this.dates = dates; } public string getstyle() {  return style; } public void tstyle(string style) {  this.style = style; }}

（5）登录页面的交互层：loginrvlet.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.rvlet;import java.io.ioexception;import java.sql.sqlexception;import javax.rvlet.rvletexception;import javax.rvlet.annotation.webrvlet;import javax.rvlet.http.httprvlet;import javax.rvlet.http.httprvletrequest;import javax.rvlet.http.httprvletrespon;import javax.rvlet.http.httpssion;import com.dao.authordao;import com.entity.author;/*** rvlet implementation class loginrvlet*/@webrvlet("/loginrvlet")public class loginrvlet extends httprvlet { private static final long rialversionuid = 1l;     /**  * @e httprvlet#httprvlet()  */  public loginrvlet() {    super();    // todo auto-generated constructor stub  } /**  * @e httprvlet#doget(httprvletrequest request, httprvletrespon respon)  */ protected void doget(httprvletrequest request, httprvletrespon respon) throws rvletexception, ioexception {  // todo auto-generated method stub  //内置对象request，respon  request.tcharacterencoding("utf-8");    httpssion ssion = request.getssion();    //获取用户输入验证码  string checkcode = request.getparameter("checkcode");  //获取ssion中的验证码,也就是codervlet中生成的四个字符  string ssioncode = (string)ssion.getattribute("scode");      //验证码正确  if(checkcode.equals(ssioncode)) {   //获取表单数据   string urname = request.getparameter("urname");   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(urname, password);         //判断     if(obj != null) {           //重新放入用户信息    //  httpssion ssion = request.getssion();      ssi搞笑祝福语on.tattribute("authorinfo", obj);      //设置ssion的有效期为10秒      ssion.tmaxinactiveinterval(10);           //页面转发      respon.ndredirect("ur.jsp");     }     el {           //页面重定向到登录页面      respon.ndredirect("index.jsp");     }  }  el {   //验证码不正确   request.tattribute("error_code", "验证码不匹配");   request.二季度思想汇报getrequestdispatcher("index.jsp").forward(request, respon);  } }  /**  * @e httprvlet#dopost(httprvletrequest request, httprvletrespon respon)  */ protected void dopost(httprvletrequest request, httprvletrespon respon) throws rvletexception, ioexception {  // todo auto-generated method stub  doget(request, respon); }}

（6）数据库查询的交互层：authorrvlet.java文件。

package com.rvlet;import java.io.ioexception;import java.util.list;import javax.rvlet.rvletexception;import javax.rvlet.annotation.webrvlet;import javax.rvlet.http.httprvlet;import javax.rvlet.http.httprvletrequest;import javax.rvlet.http.httprvletrespon;import com.dao.authordao;import com.entity.author;/*** rvlet implementation class authorrvlet*/@webrvlet("/authorrvlet")public class authorrvlet extends httprvlet { private static final long rialversionuid = 1l;     /**  * @e httprvlet#httprvlet()  */  public authorrvlet() {    super();    // todo auto-generated constructor stub  } /**  * @e httprvlet#doget(httprvletrequest request, httprvletrespon respon)  */ protected void doget(httprvletrequest request, httprvletrespon respon) throws rvletexception, ioexception {  // todo auto-generated method stub  //设置编码方式   request.tcharacterencoding("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三角恒等变换> list = ad.queryauthorlist();   request.tattribute("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authorrvlet就将信息显示出来了。   request.getrequestdispatcher("ulist.jsp").forward(request, respon);     } /**  * @e httprvlet#dopost(httprvletrequest request, httprvletrespon respon)  */ protected void dopost(httprvletrequest request, httprvletrespon respon) throws rvletexception, ioexception {  // todo auto-generated method stub  doget(request, respon); }}

（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.resultt;import java.sql.sqlexception;import java.util.arraylist;import java.util.list;import com.entity.author;public class authordao {  public author check(string urname ,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 = "lect *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.tstring(1, urname);    ps.tint(2, password);        //执行sql查询语句 , 并将执行结果放入结果集中     resultt 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.tid(rs.getint(1));      obj.tname(rs.getstring(2));      obj.tprice(rs.getint(3));      obj.tnum(rs.getint(4));      obj.tdates(rs.getstring(5));      obj.tstyle(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 = "lect *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   resultt rs = ps.executequery();      //利用循环将obj放入list集合中   while(rs.next()) {    obj = new author();        obj.tid(rs.getint(1));    obj.tname(rs.getnstring(2));    obj.tprice(rs.getint(3));    obj.tnum(rs.getint(4));    obj.tdates(rs.getstring(5));    obj.tstyle(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codervlet类，用于生成验证码。

package com.rvlet;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.rvlet.rvletexception;import javax.rvlet.rvletoutputstream;import javax.rvlet.annotation.webrvlet;import javax.rvlet.http.httprvlet;import javax.rvlet.http.httprvletrequest;import javax.rvlet.http.httprvletrespon;import javax.rvlet.http.httpssion;@webrvlet("/codervlet")public class codervlet extends httprvlet{  //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(httprvletrequest req, httprvletrespon resp) throws rvletexception, 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.tfont(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.tcolor(getcolor());   pen.drawstring(string.valueof(code.charat(i)), i*15+5, 20);;  }    //respon对象绘制图片到页面,rvle输出流进行图片的输出  rvletoutputstream sos = resp.getoutputstream();  imageio.write(image, "png", sos);    sos.flush();  sos.clo();    //验证码放入ssion  httpssion ssion = req.getssion();  ssion.tattribute("scode", code);   } @override protected void dopost(httprvletrequest req, httprvletrespon resp) throws rvletexception, 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 urname="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,urname,password); }  //用于获取conn public connection getconn() {  return conn; } public void tconn(connection conn) {  this.conn = conn; } }