今天就跟大家聊聊有关Java web如何实现一个验证码权限登录功能,可能很多人都不太了解,为了让大家更加了解,小编给大家总结了以下内容,希望大家根据这篇文章可以有所收获。
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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"?>web04 login.jsp main.jsp LoginServlet com.ningmeng.web.LoginServlet 输出验证码 This is the display name of my J2EE component PictureCheckCode com.servlet.PictureCheckCode LoginServlet /login PictureCheckCode /PictureCheckCode
login.jsp:
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>Insert title here
main.jsp:
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>Insert title here 登录成功
当前用户:${currentUser.username}
当前密码:${currentUser.password}
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+"/"; %>My JSP 'linmao.jsp' starting page This is my JSP page.
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。
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