Java web含验证码及权限登录实例代码

所用到的开发工具为myeclipse10，MySQL数据库。

首先，在myeclipse中新建一个Java web项目。

项目的结构：

数据库结构：

下面将各个包中的代码粘贴出来。

com.ningmeng.dao包

package com.ningmeng.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import com.ningmeng.model.User;
public class UserDao {
public User login(Connection con,User user) throws SQLException{
User resultUser=null;
String sql="select * from user where username=? and password=?";
PreparedStatement ps=con.prepareStatement(sql);//
ps.setString(1, user.getUsername());
ps.setString(2, user.getPassword());
ResultSet rs=ps.executeQuery();
if(rs.next()){
resultUser=new User();
resultUser.setUsername(rs.getString("username"));
resultUser.setPassword(rs.getString("password"));
}
return resultUser;
}
}

com.ningmeng.model包

package com.ningmeng.model;
public class User {
private int id;
private String username;
private String password;
public User() {
super();
}
public User(String username, String password) {
super();
this.username = username;
this.password = password;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}

com.ningmeng.util包

package com.ningmeng.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class DbUtil {
private String url="jdbc:mysql://localhost:3306/db-jsp";
private String user="root";
private String password="123";
private String driver="com.mysql.jdbc.Driver";
public Connection getCon() throws Exception{
Class.forName(driver);
Connection con=DriverManager.getConnection(url, user, password);
return con;
}
public static void getClose(Connection con) throws SQLException{
if(con!=null){
con.close();
}
}
/*public static void main(String[] args) {
DbUtil db=new DbUtil();
try {
db.getCon();
System.out.println("测试连接数据库，连接成功");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
System.out.println("测试连接数据库，连接失败");
}
}*/
}

com.ningmeng.web包

package com.ningmeng.web;
import java.io.IOException;
import java.sql.Connection;
import java.io.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.servlet.http.*;
import com.ningmeng.dao.UserDao;
import com.ningmeng.model.User;
import com.ningmeng.util.DbUtil;
public class LoginServlet extends HttpServlet{
DbUtil db=new DbUtil();
UserDao userDao=new UserDao();
/**
*
*/
private static final long serialVersionUID = 1L;
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String username=request.getParameter("username");
String password=request.getParameter("password");
String checkcode=request.getParameter("checkCode");
HttpSession session=request.getSession();
//session.getAttribute("randCheckCode");
String s = (String)session.getAttribute("randCheckCode");
if(!checkcode.equals(s))
{
response.sendRedirect("linmao.jsp");
}else{
if(request.getParameter("ra").equals("l")){
Connection con=null;
try {
User user=new User(username,password);
con=db.getCon();
User currentUser=userDao.login(con, user);
if(currentUser==null){
//System.out.println("no");
request.setAttribute("error", "用户名或者密码错误");
request.setAttribute("username", username);
request.setAttribute("password", password);
request.getRequestDispatcher("login.jsp").forward(request, response);
}else{
//System.out.println("yes");
HttpSession session1=request.getSession();
session1.setAttribute("currentUser",currentUser);
response.sendRedirect("main.jsp");
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
else{
response.sendRedirect("linmao.jsp");
}
}
}
}

com.servlet包

package com.servlet;
import java.awt.*;
import java.awt.geom.*;
import java.awt.image.*;
import java.io.*;
import java.util.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import javax.imageio.ImageIO;
public class PictureCheckCode extends HttpServlet {
private static final long serialVersionUID = 1L;
public PictureCheckCode() {
super();
}
public void destroy() {
super.destroy();
}
public void init() throws ServletException {
super.init();
}
/*该方法主要作用是获得随机生成的颜色*/
public Color getRandColor(int s,int e){
Random random=new Random ();
if(s>255) s=255;
if(e>255) e=255;
int r,g,b;
r=s+random.nextInt(e-s); //随机生成RGB颜色中的r值
g=s+random.nextInt(e-s); //随机生成RGB颜色中的g值
b=s+random.nextInt(e-s); //随机生成RGB颜色中的b值
return new Color(r,g,b);
}
@Override
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//设置不缓存图片
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "No-cache");
response.setDateHeader("Expires", 0);
//指定生成的响应图片,一定不能缺少这句话,否则错误.
response.setContentType("image/jpeg");
int width=86,height=33;  //指定生成验证码的宽度和高度
BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); //创建BufferedImage对象,其作用相当于一图片
Graphics g=image.getGraphics();  //创建Graphics对象,其作用相当于画笔
Graphics2D g2d=(Graphics2D)g;  //创建Grapchics2D对象
Random random=new Random();
Font mfont=new Font("楷体",Font.BOLD,20); //定义字体样式
g.setColor(getRandColor(200,250));
g.fillRect(0, 0, width, height); //绘制背景
g.setFont(mfont);     //设置字体
g.setColor(getRandColor(180,200));
//绘制100条颜色和位置全部为随机产生的线条,该线条为2f
for(int i=0;i<100;i++){
int x=random.nextInt(width-1);
int y=random.nextInt(height-1);
int x1=random.nextInt(6)+1;
int y1=random.nextInt(12)+1;
BasicStroke bs=new BasicStroke(2f,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL); //定制线条样式
Line2D line=new Line2D.Double(x,y,x+x1,y+y1);
g2d.setStroke(bs);
g2d.draw(line);  //绘制直线
}
//输出由英文，数字，和中文随机组成的验证文字，具体的组合方式根据生成随机数确定。
String sRand="";
String ctmp="";
int itmp=0;
//制定输出的验证码为四位
for(int i=0;i<4;i++){
switch(random.nextInt(3)){
case 1:  //生成A-Z的字母
itmp=random.nextInt(26)+65;
ctmp=String.valueOf((char)itmp);
break;
default:
itmp=random.nextInt(10)+48;
ctmp=String.valueOf((char)itmp);
break;
}
sRand+=ctmp;
Color color=new Color(20+random.nextInt(110),20+random.nextInt(110),random.nextInt(110));
g.setColor(color);
//将生成的随机数进行随机缩放并旋转制定角度 PS.建议不要对文字进行缩放与旋转,因为这样图片可能不正常显示
/*将文字旋转制定角度*/
Graphics2D g2d_word=(Graphics2D)g;
AffineTransform trans=new AffineTransform();
trans.rotate((45)*3.14/180,15*i+8,7);
/*缩放文字*/
float scaleSize=random.nextFloat()+0.8f;
if(scaleSize>1f) scaleSize=1f;
trans.scale(scaleSize, scaleSize);
g2d_word.setTransform(trans);
g.drawString(ctmp, 15*i+18, 14);
}
HttpSession session=request.getSession(true);
session.setAttribute("randCheckCode", sRand);
g.dispose(); //释放g所占用的系统资源
ImageIO.write(image,"JPEG",response.getOutputStream()); //输出图片
}
}

配置web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>web04</display-name>
<welcome-file-list>
<welcome-file>login.jsp</welcome-file>
<welcome-file>main.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>com.ningmeng.web.LoginServlet</servlet-class>
</servlet>
<servlet>
<description>输出验证码</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>PictureCheckCode</servlet-name>
<servlet-class>com.servlet.PictureCheckCode</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/login</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>PictureCheckCode</servlet-name>
<url-pattern>/PictureCheckCode</url-pattern>
</servlet-mapping>
</web-app>

login.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<script language="javascript">
function myReload() {
document.getElementById("CreateCheckCode").src = document
.getElementById("CreateCheckCode").src
+ "?nocache=" + new Date().getTime();
}
</script>
</head>
<body>
<form action="login" method="post">
<table>
<tr>
<th colspan="2">登录界面</th>
</tr>
<tr>
<td>账号：</td>
<td><input type="text" id="username" name="username" value="${username}"></td>
</tr>
<tr>
<td>密码：</td>
<td><input type="password" id="password" name="password" value="${password}"></td>
</tr>
<tr>
<td>验证码：</td>
<td><input name="checkCode" type="text" id="checkCode" title="验证码区分大小写"
size="8" ,maxlength="4" />
<img src="PictureCheckCode" id="CreateCheckCode" align="middle">
<a href="" onclick=" rel="external nofollow" myReload()"> 看不清,换一个</a>
</tr>
<tr>
<td>类型：</td>
<td>
<input type="radio" name="ra" value="l" checked="checked"/>一般研究人员
<input type="radio" name="ra" value="m" />管理员研究人员
</td>
</tr>
<tr>
<td>
<input type="submit" value="提交">
<font color="red">${error}</font>
</td>
</tr>
</table>
</form>
</body>
</html>

main.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<p>登录成功</p>
当前用户：${currentUser.username}<br/>
当前密码：${currentUser.password}<br/>
</body>
</html>

linmao.jsp:

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>" rel="external nofollow" >
<title>My JSP 'linmao.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css" rel="external nofollow" >
-->
</head>
<body>
This is my JSP page. <br>
</body>
</html>

项目现在做到验证码和权限这一块，找回密码功能还没有做完，结构中Check.jsp还用不到。还有连接数据库的操作，就不详细叙述了。

账号和密码在数据库的表中

以上所述是小编给大家介绍的Java web含验证码及权限登录实例代码，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对脚本之家网站的支持！

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