使用MVC思想的简单的登录与注册功能实现

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需求

1.带有验证码的注册
2.登录功能
3.各项信息不符合规范后进行错误信息的提示
4.表单数据的回显
5.服务器端的表单验证

思路

1.注册：regist.jsp–>RegistServlet.java–>UserService.java#regist()–> UserDao.java
2.登录：login.jsp–>LoginServlet.java–>UserLogin.java#login(User form)–>UserDao.java
3.使用VerifyCode类实现验证码。
4.使用request域保存数据的回显和错误信息。
5.使用request域保存数据表单校验信息。
6.登录成功后使用session域保存用户信息。
7.使用XML实现持久层数据的操作。
8.使用CommonUtils自动封装用户对象。

项目的结构图

UserDao.java

使用的是XML，通过dom4j获取到xml文件中的键值对。

package cn.wang.user.dao;

import java.io.FileOutputStream;
import java.io.OutputStreamWriter;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

import cn.wang.user.domain.User;

/*
 *数据类 ：BUG pass
 */
/**
 * 
 * @author Zi Jian Wang
 *
 */
public class UserDao {

	private String path = "C:/user.xml";// 依赖数据文件

	// 按用户名查询用户对象
	public User findByUserName(String username) {
		// 得到Document,创建解析器
		SAXReader reader = new SAXReader();
		try {
			Document doc = reader.read(path);

			Element element = (Element) doc.selectSingleNode("//user[@username='" + username + "']");
			// .xpath查询，如果为null，返回null
			if (element == null) {
				System.out.println("没查到！");
				return null;
			}
			// 如果不为null，需要把Element封装到User对象中
			User user = new User();
			String name = element.attributeValue("username");// 获取该元素的名为username的属性值
			String psw = element.attributeValue("password");// 获取名为username的password的属性值
			user.setUsername(name);
			user.setUserpassword(psw);
			return user;
		} catch (DocumentException e) {
			throw new RuntimeException(e);
		}
	}

	// 插入一个用户到数据库中
	public void insertUser(User user) {
		// 得到document
		SAXReader reader = new SAXReader();
		try {
			// 通过Document得到Root元素！<users>
			Document doc = reader.read(path);
			// 使用参数user，转换成Element对象
			Element root = doc.getRootElement();
			// 把element添加到root元素中
			Element userEle = root.addElement("user");
			userEle.addAttribute("username", user.getUsername());
			userEle.addAttribute("password", user.getUserpassword());
			// 保存代码
			OutputFormat format = new OutputFormat("\t", true);// 缩进使用\t,是否换行，使用true
			format.setTrimText(true);// 清空原有的换行和缩进
			// 创建xmlWriter
			XMLWriter writer;
			try {
				writer = new XMLWriter(new OutputStreamWriter(new FileOutputStream(path), "utf-8"), format);
				writer.write(doc);
				writer.close();
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		} catch (DocumentException e) {
			throw new RuntimeException();
		}
	}
}

User.java

实体类，3个属性：用户名，密码，验证码

package cn.wang.user.domain;

/*
 *User实体类 
 */
/**
 * 
 * @author Zi Jian Wang
 *
 */

public class User {

	private String username;
	private String userpassword;
	private String verifyCode;

	public String getVerifyCode() {
		return verifyCode;
	}

	public void setVerifyCode(String verifyCode) {
		this.verifyCode = verifyCode;
	}


	public User(String username, String userpassword, String verifyCode) {
		super();
		this.username = username;
		this.userpassword = userpassword;
		this.verifyCode = verifyCode;
	}

	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

	public String getUserpassword() {
		return userpassword;
	}

	public void setUserpassword(String userpassword) {
		this.userpassword = userpassword;
	}

	public User() {
		super();
		// TODO Auto-generated constructor stub
	}

}

UserException

自定义的异常类，只是给出父类中的构造器 ，方便用来创建对象。

package cn.wang.user.service;

/**
 * 自定义的异常类，只是给出父类中的构造器 ，方便用来创建对象。
 * 
 * @author Zijian Wang
 *
 */
public class UserException extends Exception {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	public UserException() {
		super();
	}

	public UserException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
		super(message, cause, enableSuppression, writableStackTrace);
	}

	public UserException(String message, Throwable cause) {
		super(message, cause);
		// TODO Auto-generated constructor stub
	}

	public UserException(String message) {
		super(message);
		// TODO Auto-generated constructor stub
	}

	public UserException(Throwable cause) {
		super(cause);
		// TODO Auto-generated constructor stub
	}

}

UserService.java

业务逻辑类：2个功能：登录，注册

package cn.wang.user.service;

import cn.wang.user.dao.UserDao;
import cn.wang.user.domain.User;
/**
 * 
 * @author ZiJian Wang
 *
 */
public class UserService {

	private UserDao dao = new UserDao();
	
	/*
	 * 注册
	 */
	// 没有返回值，但是注册失败会抛出一个自定义的异常
	public void regist(User user) throws UserException {
		// 检测注册用户是否已经注册了
		User find_user = dao.findByUserName(user.getUsername());
		if (find_user != null)
			throw new UserException("用户名：" + user.getUsername() + "，已经被注册！");
		dao.insertUser(user);
		// 添加用户
	}
	/*
	 * 登录功能
	 */
	public User login(User user_form) throws UserException {
		// 使用form中username进行查询

		User user = dao.findByUserName(user_form.getUsername());
		// 如果user为空，就抛出错误信息：“用户名不存在”
		if (user == null)
			throw new UserException("用户名不存在！");
		// 比较user的password，如果不存在
		if (!user_form.getUserpassword().equals(user.getUserpassword())) {
			throw new UserException("密码错误！");
		}
		return user;
	}
}

registServlet.java

注册Servlet类：登录的Servlet大同小异，不列出来了就。

package cn.wang.web.servlet;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

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

import cn.wang.user.domain.User;
import cn.wang.user.service.UserException;
import cn.wang.user.service.UserService;
import cn.wang.utils.CommonUtils;
/**
 * 
 * @author ZiJian Wang
 *
 */
public class RegistServlet extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		request.setCharacterEncoding("utf-8");// 请求编码
		response.setContentType("text/html;charset=UTF-8");// 响应编码
		// 依赖UserService
		UserService service = new UserService();
		// 使用CommonUtils封装页面获取的属性的值
		// 注意！！！使用这个获取的属性的必须和对象对应属性名相同！
		User user_form = CommonUtils.toBean(request.getParameterMap(), User.class);
		// 校验表单
		// 创建map用来装载表单的错误信息
		Map<String, String> errs = new HashMap<String, String>();
		// 用户名校验
		String username = user_form.getUsername();
		if (username == null || username.trim().isEmpty()) {
			errs.put("username", "用户名不能为空！");
		} else if (username.length() < 3 || username.length() > 15) {
			errs.put("username", "用户名长度在3~15之间");
		}
		// 密码校验
		String userpassword = user_form.getUserpassword();
		if (userpassword == null || userpassword.trim().isEmpty()) {
			errs.put("userpassword", "密码不能为空！");
		} else if (userpassword.length() < 3 || userpassword.length() > 15) {
			errs.put("userpassword", "密码长度在3~15之间");
		}
		// 验证码校验
		String session_Vcode = (String) request.getSession().getAttribute("image_msg");
		String verifyCode = user_form.getVerifyCode();
		if (verifyCode == null || verifyCode.trim().isEmpty()) {
			errs.put("verifyCode", "验证码不能为空！");
		} else if (verifyCode.length() != 4) {
			errs.put("verifyCode", "验证码的长度必须为4！");
		} else if (!verifyCode.equalsIgnoreCase(session_Vcode)) {
			errs.put("verifyCode", "验证码不正确！");
		}
		// 判断map是否为空（不为空说明存在错误）
		if (errs != null && errs.size() > 0) {
			// 保存errs到request域
			request.setAttribute("errs", errs);
			// 保存用户的user_form到request域
			request.setAttribute("user", user_form);
			// 转发到regist.jsp
			request.getRequestDispatcher("page/regist.jsp").forward(request, response);
			return;
		}
		try {
			service.regist(user_form);
			response.getWriter().print("<h1>注册成功！</h1><a href='/page/login.jsp'>点击去登陆</a>");
		} catch (UserException e) {
			// 如果注册失败把失败的信息保存到request域中
			request.setAttribute("msg", e.getMessage());
			request.setAttribute("user", user_form);
			request.getRequestDispatcher("page/regist.jsp").forward(request, response);
		}
	}
}

VerifyCodeServlet.java

package cn.wang.web.servlet;

import java.awt.image.BufferedImage;
import java.io.IOException;

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

import utils.VerifyCode;
/**
 * 
 * @author ZiJian Wang
 *
 */
public class VerifyCodeServlet extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		// 创建验证码类
		VerifyCode code = new VerifyCode();
		// 生成BuffImage对象,生成对象。
		BufferedImage image = code.createImage();
		// 把图片上的文本保存到session域中
		String image_msg = code.getText();
 		request.getSession().setAttribute("image_msg", image_msg);
		// 把图片响应给客户端
		VerifyCode.output(image, response.getOutputStream());
	}
}

regist.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%
	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%>">

<title>My JSP 'regist.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">
<style type="text/css">
</style>
<script type="text/javascript">
	function change() {
		//获取<img>元素
		var v_code = document.getElementById("v_code");
		//重新赋值src路径，既重新加载VerifyCodeServlet
		v_code.src = "<c:url value='/VerifyCodeServlet'/>?time=" + new Date().getTime();
	}
</script>
</head>
<body>
	<div style="margin-left: 300px">
		<h1 style="margin-left: 100px">注册</h1>
		<p style="color: red;font-weight:900 ">${msg}</p>
		<form action="RegistServlet" method="post">
			账号： <input type="text" name="username" value="${user.username }"> <span style="color:red">${errs.username}</span>
			<br>密码： <input type="text" name="userpassword" value="${user.userpassword}"><span
				style="color:red">${errs.userpassword}</span><br>验证码：<input type="text"
				value="${user.verifyCode}" name="verifyCode" size="3"><img id="v_code"
				src="<c:url value='/VerifyCodeServlet'/>" style="margin-top: 10px;" /><span style="color:red">${errs.verifyCode}</span><br>
			<a href="javascript:change()" style="margin-left: 100px">换一张</a><br> <input type="submit"
				value="提交" style="margin-left: 100px">
			<!--验证码-->
		</form>
	</div>
</body>
</html>

login.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%
	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%>">

<title>My JSP 'Login.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">
</head>
<body>
<h1>登陆</h1>
	<p style="color: red;font-weight:900 ">${msg}</p>
	<form action="<c:url value='/LoginServlet'/>" method="post">
		用户名： <input type="text" name="username" value="${user.username}"><br> 密码：<input
			type="text" name="userpassword" value="${user.userpassword}"><br> <input
			type="submit" value="提交">
	</form>
</body>
</html>

welcome.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%
	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%>">

<title>My JSP 'webcome.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">
</head>

<body>
	<h1>登录成功</h1>
	<c:choose>
		<c:when test="${empty sessionScope.session_user}"><a href="page/login.jsp">请点击这里登录</a></c:when>
		<c:otherwise>${sessionScope.session_user}</c:otherwise>
	</c:choose>
</body>
</html>

项目文件包：