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
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。
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！