黑马day07 登录注冊案例(一)

简单介绍：依据三层架构的思想设计本案例。

1.搭建好开发环境

准备好须要的包和模拟数据库配置文件users.xml

-->cn.itheima.dao

-->cn.itheima.service

-->cn.itheima.domain

-->cn.itheima.web

-->cn.itheima.utils

-->cn.itheima.exception

-->cn.itheima.test

2.建立模拟数据库users.xml

<?xml version="1.0" encoding="UTF-8"?>
<users>
	<user username="admin" password="admin" nickname="admin" email="admin@qq.com"></user>
</users>

3.建立javaBean users

package cn.itheima.domain;

import cn.itheima.exception.MsgException;

public class User {
	private String username;
	private String password;
	private String password2;
	private String nickname;
	private String email;
	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;
	}
	public String getPassword2() {
		return password2;
	}
	public void setPassword2(String password2) {
		this.password2 = password2;
	}
	public String getNickname() {
		return nickname;
	}
	public void setNickname(String nickname) {
		this.nickname = nickname;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public void check()throws MsgException{
		if(username==null || "".equals(username)){
			throw new MsgException("用户名不能为空!");
		}
		if(password==null || "".equals(password)){
			throw new MsgException("密码不能为空!");
		}
		if(password2==null || "".equals(password2)){
			throw new MsgException("确认密码不能为空!");
		}
		if(!password.equals(password2)){
			throw new MsgException("两次密码不一致!");
		}
		if(nickname==null || "".equals(nickname)){
			throw new MsgException("昵称不能为空!");
		}
		if(email==null || "".equals(email)){
			throw new MsgException("邮箱不能为空!");
		}
		if(!email.matches("^\\w+@\\w+(\\.\\w+)+$")){
			throw new MsgException("邮箱格式不对!");
		}
	}

}

4.建立UserDao...实现对应的查询和加入功能(主要通过使用dom树操作xml文件)

package cn.itheima.dao;

import java.util.List;

import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;

import cn.itheima.domain.User;
import cn.itheima.utils.XmlUtil;

public class XmlUserDao {
	/***
	 * 依据用户名查询用户
	 * @param username用户名
	 * @return 依据用户名找到用户的信息封装到javaBean中，没有返回null
	 */
	public User findUserByUsername(String username){
		Document doc = XmlUtil.getDocument();
		Element root = doc.getRootElement();
		List<Element> list = root.selectNodes("//user[@username='"+username+"']");
		if(list.size()>0){//假设找到这个用户就封装到bean中返回user
			Element userEle = list.get(0);
			User user=new User();
			user.setUsername(userEle.attributeValue("username"));
			user.setPassword(userEle.attributeValue("password"));
			user.setNickname(userEle.attributeValue("nickname"));
			user.setEmail(userEle.attributeValue("email"));
			return user;
		}else{//没有找到用户
			return null;
		}

	}
	/**
	 * 通过username与password查找用户，找到就封装到javaBean中，找不到返回null
	 * @param username
	 * @param password
	 * @return
	 */
	public User findUserByUserNameAndPassword(String username,String password){
		Document doc = XmlUtil.getDocument();
		Element root = doc.getRootElement();
		List<Element> list = root.selectNodes("//user[@username='"+username+"' and @password='"+password+"']");
		if(list.size()>0){//假设找到这个用户就封装到bean中返回user
			Element userEle = list.get(0);
			User user=new User();
			user.setUsername(userEle.attributeValue("username"));
			user.setPassword(userEle.attributeValue("password"));
			user.setNickname(userEle.attributeValue("nickname"));
			user.setEmail(userEle.attributeValue("email"));
			return user;
		}else{//没有找到用户
			return null;
		}
	}
	/**
	 * 加入一个用户到数据库中
	 * @param user
	 */
	public void addUserToXml(User user){
		Document doc = XmlUtil.getDocument();
		Element root = doc.getRootElement();
		//1.凭空创建一个<user>标签，并设置属性
		Element userEle = DocumentHelper.createElement("user");
		userEle.setAttributeValue("username", user.getUsername());
		userEle.setAttributeValue("password", user.getPassword());
		userEle.setAttributeValue("nickname", user.getNickname());
		userEle.setAttributeValue("email", user.getEmail());
		//2.挂在到root标签下
		root.add(userEle);
		//3.改动xml文件
		XmlUtil.updateXml();

	}
}

5.建立一个工具类提供获取document和改动xml的方法

package cn.itheima.utils;

import java.io.FileOutputStream;
import java.io.IOException;

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

public class XmlUtil {
	private static Document doc=null;
	private static String  path=XmlUtil.class.getClassLoader().getResource("users.xml").getPath();
	static{
		SAXReader reader=new SAXReader();
		try {
			doc = reader.read(path);
		} catch (DocumentException e) {
			e.printStackTrace();
		}
	}
	/**
	 * 返回文档对象
	 * @return
	 */
	public static Document getDocument(){
		return doc;
	}
	/**
	 * 改动xml文件
	 */
	public  static void updateXml(){
		try {
			XMLWriter writer=new XMLWriter(new FileOutputStream(path),OutputFormat.createPrettyPrint());
			writer.write(doc);
			writer.close();
		} catch (IOException e) {
			e.printStackTrace();
			throw new RuntimeException();
		}
	}
}

6.开发service 提供方法注冊的方法和检查username和password的方法

package cn.itheima.service;

import cn.itheima.dao.XmlUserDao;
import cn.itheima.domain.User;
import cn.itheima.exception.MsgException;

public class UserSevice {
	XmlUserDao dao=new XmlUserDao();
	/**
	 * 注冊用户
	 * @param user
	 * @throws MsgException
	 */
	public void registUser(User user) throws MsgException{
		//1.推断数据库中是不是实用户了
		if(dao.findUserByUsername(user.getUsername())!=null){
			throw new MsgException("用户已经存在");
		}
		//2.加入到数据库中
		dao.addUserToXml(user);
	}
	/**
	 * 检查username与password是否正确
	 * @param username
	 * @param password
	 * @return
	 */
	public User isUser(String username,String password){
		return dao.findUserByUserNameAndPassword(username, password);
	}
}

7.建立异常类MsgExcetion

package cn.itheima.exception;
public class MsgException extends Exception {
	public MsgException() {
	}
	public MsgException(String msg) {
		super(msg);
	}
}

8.开发案例的主页面index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
  </head>

  <body>
  	<c:if test="${sessionScope.user==null }">
  		欢迎光临 游客！<hr/><a href="${pageContext.request.contextPath}/regist.jsp">注冊</a><hr><a href="${pageContext.request.contextPath}/login.jsp">登录</a>
  	</c:if>
  	<c:if test="${sessionScope.user!=null}">
  		欢迎光临${sessionScope.user.username }！

<hr><a href="${pageContext.request.contextPath}/login.jsp">登录</a><hr/><a href="${pageContext.request.contextPath}/servlet/LogoutServlet">注销</a>
  	</c:if>
  </body>
</html>

执行结果示意图：