注册登录系统（jsp+servlet）

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注册登录系统（jsp+servlet）

2024-08-23 21:26:06 212人阅读

package webdemo;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class DBServlet extends HttpServlet {
	//用于连接数据库的Connection对象
	protected java.sql.Connection conn = null;
	//执行各种SQL语句的方法
	protected java.sql.ResultSet execSQL(String sql,Object...args)
			throws Exception
	{
		//建立PreparedStatement对象
		java.sql.PreparedStatement pStmt = conn.prepareStatement(sql);
		//为pSmt 对象设置SQL参数值
		for(int i=0;i<args.length;i++){
			pStmt.setObject(i+1, args[i]);  //设置SQL参数集
		}
		pStmt.execute();   //执行SQL语句	
		return pStmt.getResultSet();
	}
	
	// 核对用户输入的验证码是否合法
	protected boolean checkValidationCode(HttpServletRequest request,String validationCode){
		String validationCodeSession = (String) request.getSession().getAttribute("validation_code");
		
		if(validationCodeSession == null){         //获得验证码是null的话
　　　　　　　　　　　　　　//设置result.jsp需要的结果信息
			request.setAttribute("info", "验证码过期");
			//设置login.jsp需要的错误信息
			request.setAttribute("codeError","验证码过期");
			return false;
		}
		if(validationCode.equalsIgnoreCase(validationCodeSession)==false){//两个验证码比较
			request.setAttribute("info", "验证码过期");
			
			request.setAttribute("codeError","验证码过期");
			return false;
		}
		return true;
	}

	@Override
	protected void service(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		try{
			if(conn == null){
				//创建上下文对象
				javax.naming.Context ctx = new javax.naming.InitialContext();
				//获取数据源
				javax.sql.DataSource ds = (javax.sql.DataSource) ctx.lookup("java:/comp/env/jdbc/webdb");
				conn = ds.getConnection();  //为connection赋值
			}
		}catch (Exception e)
		{}
	}

	@Override
	public void destroy() {
		try{
			if(conn!=null){
				conn.close();
			}
		}catch(Exception e)
		{}
	}
	
}

另一种写法：

Connection cn=null;
Class.forName("com.mysql.jdbc.Driver").newInstance();
String url="jdbc:mysql://localhost:3306/t_user?useUnicode=true&characterEncoding=GBK";
String user="root";
 String password="root";
 cn=DriverManager.getConnection(url,user,password);

在Tomcat的Server.xml中配置

<Context path="/webdemo" docBase="webdemo" debug="0">
      <Resource name="jdbc/webdb" auth="Container"
               type="javax.sql.DataSource"
               driverClassName="com.mysql.jdbc.Driver"
               url="jdbc:mysql://localhost:3306/webdb?characterEncoding=UTF-8"
               username="root"
               password="1234"              
               maxActive="200"
               maxIdle="50"
               maxWait="3000"/>
</Context>

Register继承DBServlet　　

package webdemo;

import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class Register extends DBServlet {

	@Override
	protected void service(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		String userName = null;
		
		if(request.getParameter("login")!=null){
			response.sendRedirect("/webdemo/login.jsp");//重定向写绝对路径
			return;
		}
		
		try{
			super.service(request, response); //打开数据库
			
			userName = request.getParameter("username");
			String password = request.getParameter("password");
			String email = request.getParameter("email");
			String validationCode = request.getParameter("validation_code");
			
			if(userName==null||password==null||validationCode==null){
				return;
			}
			if(userName.equals("")||password.equals("")||validationCode.equals("")){
				return;
			}
			
			//进行编码转换，以支持中文用户名
			userName = new String(userName.getBytes("ISO-8859-1"),"UTF-8");
			
			request.setAttribute("page", "/webdemo/register.jsp");//requestScope里面可以调用 绝对地址   跳转register.jsp
			
			if(!checkValidationCode(request,validationCode)){
				return;
			}
			email = (email == null)?"":email;
			
			String passwordMD5 = webdemo.Encrypter.md5Encrypt(password);
			
			String sql = "insert into t_users(user_name,password_md5,email) values(?,?,?)";
			
			execSQL(sql,userName,passwordMD5,email);
			
			request.setAttribute("info", "用户注册成功！");
		}catch(Exception e){
			System.out.println(e.getMessage());
			request.setAttribute("info", userName+"已经被使用！");
		}
		finally{
			RequestDispatcher rd =request.getRequestDispatcher("/result.jsp");
			rd.forward(request, response);
		}
	}
	
}

　response.sendRedirect("/webdemo/login.jsp");//重定向写绝对路径

　request.setAttribute("page", "/webdemo/register.jsp");//requestScope里面可以调用绝对地址跳转register.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>
<title>注册系统</title>
<script type="text/javascript">
	function refresh(){
		var img = document.getElementById("img_validation_code");
		var time= new Date().getTime();
		//refresh 验证码重新输出  
		img.src="http://www.mamicode.com//servlet/ValidationCode?d="+time;
	}
	function checkEmail(email){
		var email = email.value;
		var pattern = /^([a-zA-Z0-9._-])+@([a-zA-Z0-9._-])+(\.[a-zA-Z0-9._-])+/;
		
		flag = pattern.test(email);
		
		if(!flag){
			alert("email格式不正确！");
			email.focus();
			return false;
		}
		return true;
	}
	function checkRegister(){
		var username = document.getElementById("username");
		if(username.value =http://www.mamicode.com/=""){
			alert("必须输入用户名！");
			username.focus();
			return;
		}
		
		var password = document.getElementById("password");
		if(password.value =http://www.mamicode.com/=""){
			alert("必须输入密码！");
			password.focus();
			return;
		}
		
		var repassword = document.getElementById("repassword");
		if(repassword.value != password.value){
			alert("输入的密码不一致!");
			repassword.focus();
			return;
		}
		
		var email = document.getElementById("email");
		if(email.value != ""){
			if(!checkEmail(email)){
				return;
			}
		}
		
		var validation_code = document.getElementById("validation_code");
		if(validation_code.value =http://www.mamicode.com/=""){
			alert("验证码必须输入");
			validation_code.focus();
			return;
		}
		register_form.submit();  //提交用户注册信息
	}
</script>
</head>
<body>
<form name="register_form" action="/webdemo/servlet/Register" method="post">
	<span class="require">*</span>用户名： 
	<input type="text" id="username" name="username" size="30" maxLength="30"/><div/>
	<span class="require">*</span>密码：
	<input type="password" id="password" name="password" size="30" maxLength="30"/><div/>
	<span class="require">*</span>请再次输入密码：
	<input type="password" id="repassword" name="repassword" size="30" maxLength="30"/><div/>
	邮箱地址：
	<input type="text" id="email" name="email" size="30" maxLength="30"/><div/>
	<span class="require">*</span>验证码：
	<input type="text" id="validation_code" name="validation_code" style="width:60px;margin-top:2px" size="30" maxLength="30"/>
	<img id="img_validation_code" src="http://www.mamicode.com//servlet/ValidationCode"/>
	<input type="button" value="http://www.mamicode.com/刷新" onclick="refresh()"/><div/>
	<input type="button" value="http://www.mamicode.com/注册" onclick="checkRegister()"/>
	<input type="submit" value="http://www.mamicode.com/登录" name="login"/>
</form>
</body>
</html>

　img.src="http://www.mamicode.com//servlet/ValidationCode?d="+time;//验证码刷新

register_form.submit(); //提交用户注册信息

　Login继承DBServlet

package webdemo;

import java.io.IOException;
import java.sql.ResultSet;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;



public class Login extends DBServlet {

	@Override
	protected void service(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		if(request.getParameter("register")!=null){
			response.sendRedirect("/webdemo/register.jsp");
			return;
		}
		String page = "/login.jsp";
		String userName = "";
		try{
			super.service(request, response);
			userName = request.getParameter("username");
			
			String password = request.getParameter("password");
			
			String validationCode = request.getParameter("validation_code");
			
			if(userName == null||password == null||validationCode == null){
				return;
			}
			if(userName.equals("")||password.equals("")||validationCode.equals("")){
				return;
			}
			userName = new String(userName.getBytes("ISO-8859-1"),"utf-8");
			
			if(!checkValidationCode(request,validationCode)){
				return;
			}
			String sql = "select user_name,password_md5 from t_users where user_name = ?";
			
			ResultSet rs = execSQL(sql, new Object[] { userName });
			if(rs.next() == false){
				request.setAttribute("userError", userName+"不存在");
			}
			else{
				String passwordMD5 = webdemo.Encrypter.md5Encrypt(password);
				if(!rs.getString("password_md5").equals(passwordMD5)){
					request.setAttribute("passwordError", "密码不正确");
				}
				else{
					page = "/main.jsp";
				}
			}
		}catch(Exception e){
			
		}
		finally{
			request.setAttribute("username", userName);
			RequestDispatcher rd = request.getRequestDispatcher(page);
			rd.forward(request, response);
		}
	}
	
}

<%@ page language="java" pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>登录系统</title>
<script type="text/javascript">
	function refresh(){
		var img = document.getElementById("img_validation_code");
		var time= new Date().getTime();
		//refresh 验证码重新输出  
		img.src="http://www.mamicode.com//servlet/ValidationCode?d="+time;
	}
	function checkLogin(){
		var username = document.getElementById("username");
		if(username.value =http://www.mamicode.com/=""){
			alert("必须输入用户名！");
			username.focus();
			return;
		}
		
		var password = document.getElementById("password");
		if(password.value =http://www.mamicode.com/=""){
			alert("必须输入密码！");
			password.focus();
			return;
		}
		
		var validation_code = document.getElementById("validation_code");
		if(validation_code.value =http://www.mamicode.com/=""){
			alert("验证码必须输入");
			validation_code.focus();
			return;
		}
		login_form.submit();  //提交用户注册信息
	}
</script>
</head>
<body>
<form name="login_form" action="/webdemo/servlet/Login" method="post">
	用户名：
	<input type="text" id="username" value="http://www.mamicode.com/${requestScope.username }" class="input_list" name="username" size="30" 
		maxLength="30"/>
	<font color="#FF0000">${requestScope.userError }</font><div/>
	密码：
	<input type="password" id="password" class="input_list" name="password" size="30" maxLength="30"/>
	<font color="#FF0000">${requestScope.passwordError }</font><div/>
	验证码:
	<input type="text" id="validation_code" name="validation_code" style="width:60px;margin-top:2px" size="30" 
		maxLength="30"/>
	<img id="img_validation_code" src="http://www.mamicode.com//servlet/ValidationCode"/>
	<input type="button" value="http://www.mamicode.com/刷新" onclick="refresh()"/>
	<font color="#ff0000">${requestScope.codeError }</font><div/>
	<input type="button" value="http://www.mamicode.com/登录" name="login" onclick="checkLogin()"/>
	<input type="submit" value="http://www.mamicode.com/注册" name="register"/>
</form>
</body>
</html>

ValidationCode

package webdemo;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class ValidationCode extends HttpServlet {
	private static String codeChars = 
			"%#23456789qwaszxerdfcvtgbnhyujmkioplZAQWSXCDERFVBGTYHNMJUIKLOP";
	private static Color getRandomColor(int minColor,int maxColor){
		Random random = new Random();
		//保存minColor 最大不会超过255
		if(minColor > 255){
			minColor = 255;
		}
		if(maxColor > 255){
			maxColor = 255;
		}
		
		int red = minColor + random.nextInt(maxColor-minColor);
		int green = minColor + random.nextInt(maxColor-minColor);
		int blue = minColor +random.nextInt(maxColor-minColor);
		return new Color(red,green,blue);
	}
	@Override
	protected void service(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		int charsLength = codeChars.length();
		
		//下面三句关闭客户端浏览器的缓冲区
		response.setHeader("ragma","No-cache");
		response.setHeader("Cache-Control", "no-cache");
		response.setDateHeader("Expires",0);
		
		//设置图形验证码的长和宽
		int width=90,height=20;
		BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
		//获得用于输出文字的Graphics对象
		Graphics g = image.getGraphics();
		Random random=new Random();
		g.setColor(getRandomColor(180,250));
		g.fillRect(0, 0, width, height);
		
		g.setFont(new Font("Times New Roman",Font.ITALIC,height));
		g.setColor(getRandomColor(120,180));
		
		StringBuilder validationCode = new StringBuilder();
		
		String[] fontNames = {"Times New Roman","Book antiqua","Arial"};
		
		for (int i=0;i<3+random.nextInt(3);i++){
			g.setFont(new Font(fontNames[random.nextInt(3)],Font.ITALIC,height));
			
			char codeChar=codeChars.charAt(random.nextInt(charsLength));
			validationCode.append(codeChar);
			
			g.setColor(getRandomColor(10,100));
			
			g.drawString(String.valueOf(codeChar), 16*i+random.nextInt(7), height-random.nextInt(6));
		}
		
		HttpSession session = request.getSession();    //session存储验证码
		
		session.setMaxInactiveInterval(5*60);
		
		session.setAttribute("validation_code", validationCode.toString()); //在注册页面使用 用session在图上打印
		
		g.dispose();
		OutputStream os = response.getOutputStream();
		ImageIO.write(image, "JPEG", os);
	}
	
}

注册登录系统（jsp+servlet）

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注册登录系统（jsp+servlet）

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