MVC模式实现注册登录

很多人对MVC模式搞不懂，刚开始是我也犯迷糊，知道看到一个前辈写的代码，我顿时有的恍然大悟，拿来分享给各位

MVC：

就是M：模型、V：视图（前台界面）C：后台处理的servlet

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话不多说、上代码

bean中代码（用到的变量）

package bean;

public class Userbean {

     private String username;//用户名
     private String phone;
     private String email;
     private String password;//密码都是与数据库匹配的，下面是set和get函数

    public String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = 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;
    }

}

com.Dao中代码（对数据库增删改查操作）

package com.Dao;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import com.DBUtil.DBUtil;;
public class userDao {
    public int login(String name,String password) {
        Connection conn = DBUtil.getConn();//这里就是从DBUtil类里面得到连接
        Statement sql=null;
        ResultSet rs=null;
        try{
            sql = conn.createStatement();
        }catch(SQLException e){
            System.out.println(e);
        }
     int flag=0;
     try
     {
         rs = sql.executeQuery("select * from customer where name='"+name+"' and password='"+password+"'");
         if(rs.next())
         {
             if(rs.getString("password").equals(password))
             {
                 flag=1;
             }
         }
     }
     catch(Exception e)
     {
         e.printStackTrace();
     }

     finally
     {
         DBUtil.close(rs, sql, conn);
     }
     return flag;
 }    

}

com.DbUtil中代码（连接数据库，返回conn）

package com.DBUtil;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.sql.Statement;

    public class DBUtil
    {       static String driver="com.microsoft.sqlserver.jdbc.SQLServerDriver";
              static String url = "jdbc:sqlserver://127.0.0.1:1433;DatabaseName=BookShop";
            static String user1="sa";
            static String pwd = "8000153";
            public static Connection getConn()//获取连接，返回Connection类型，必须设置为static这样才能在其他类中使用
            {
                Connection conn=null;
                try
                {
                    Class.forName(driver);//加载驱动
                    conn=DriverManager.getConnection(url,user1,pwd);//连接数据库
                }
                catch(Exception e)
                {
                    e.printStackTrace();
                }
                return conn;
            }
            public static void close(Statement state,Connection conn)//关闭函数
            {
                if(state!=null)//只有状态和连接时，先关闭状态
                {
                    try
                    {
                        state.close();
                    }
                    catch(SQLException e)
                    {
                        e.printStackTrace();
                    }
                }
                if(conn!=null)
                {
                    try
                    {
                        conn.close();
                    }
                    catch(SQLException e)
                    {
                         e.printStackTrace();
                    }
                }
            }
            public static void close(ResultSet rs,Statement state,Connection conn)
            {
                if(rs!=null)//有结果集，状态和连接时，先关闭结果集，在关闭状态，在关闭连接
                {
                    try
                    {
                        rs.close();
                    }
                    catch(SQLException e)
                    {
                        e.printStackTrace();
                    }
                }
                if(state!=null)

                {
                    try
                    {
                        state.close();
                    }
                    catch(SQLException e)
                    {
                        e.printStackTrace();
                    }
                }
                if(conn!=null)
                {
                    try
                    {
                        conn.close();
                    }
                    catch(SQLException e)
                    {
                        e.printStackTrace();
                    }
                }
            }

        }
    

servlet中代码（要配置web.xml文件，处理完以后把值传给前台界面）

package com.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import com.Dao.userDao;
import bean.Userbean;

@WebServlet("/Userservlet")
public class Userservlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public Userservlet() {
        super();

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
                //1.
                Userbean usermessage=new Userbean();
                //2.
                HttpSession session=request.getSession();
                //3.
                String username=request.getParameter("username");
                String password=request.getParameter("password");
                //4.
                usermessage.setUsername(username);
                usermessage.setPassword(password);
                 userDao userdao = new userDao();//创建Userdao的实例
                    int flag = userdao.login(username, password);//用来判断是否登陆成功
                    if(flag==1)
                    {
                        session.setAttribute("username", "username");
                        response.sendRedirect("Showbookservlet");
                    }
                    else
                    {
                        response.getWriter().print("<script language='javascript'>alert('ERROR')</script>");
                        response.setHeader("refresh", "1;URL=Enter.html");

                    }    

    }

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

        doGet(request, response);
    }

}

xml文件配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>BookShop</display-name>
    <servlet>
        <servlet-name>Userservlet</servlet-name><!--servlet的别名，随便取  -->
        <!--servlet的包路径，后面再加上.servlet类名 ，这里的类名必须是包下面的servlet类名，目的是让找到该servlet的路径 -->
        <servlet-class>com.servlet.Userservlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>Userservlet</servlet-name><!--servlet的别名，和上面保持一致就行  -->
        <!--jsp跳转到servlet的路径名，自己取，用来从jsp界面跳转到servlet的路径，程序会根据路径找到servlet的位置  -->
        <url-pattern>/Servlet/Userservlet</url-pattern><!--  -->
    </servlet-mapping>

前台界面代码（如果想高端大气上档次可以在网上找一些css的样式）

<!DOCTYPE html>
<html lang="en">
<head>
  <title>登录</title>
  <!-- Meta tags -->
  <meta name="viewport" content="width=device-width, initial-scale=1" />
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <meta name="keywords" content=""
     />
  <script>
     addEventListener("load", function ()
             { setTimeout(hideURLbar, 0); }, false);
     function hideURLbar() { window.scrollTo(0, 1); }
  </script>
  <!-- Meta tags -->
  <!--stylesheets-->
  <link href="css/style.css" rel='stylesheet' type='text/css' media="all">
  <!--//style sheet end here-->
  <link href="http://fonts.googleapis.com/css?family=Source+Sans+Pro:400,600,700" rel="stylesheet">
</head>
<body>
  <div class="mid-class">
     <div class="art-right-w3ls">
        <h2>登      录      界       面</h2>
        <form action="Userservlet" method="get">
           <div class="main">
              <div class="form-left-to-w3l">
                 <input type="text" name="username" placeholder="Username" >
              </div>
              <div class="form-left-to-w3l ">
                 <input type="password" name="password" placeholder="Password" >
                 <div class="clear"></div>
              </div>
           </div>
           <div class="left-side-forget">
              <input type="checkbox" class="checked">
              <span class="remenber-me">记住我</span>
           </div>
           <div class="right-side-forget">
              <a href="changepassword.jsp" class="for">忘记密码?</a>
           </div>
           <div class="clear"></div>
           <div class="btnn">
              <button type="submit">登录</button>
           </div>
        </form>
        <div class="w3layouts_more-buttn">
           <h3>没有账号?
              <a href="#content1">注册
              </a>
           </h3>
        </div>

     </div>
     <div class="art-left-w3ls">
        <h1 class="header-w3ls">
           Gaze sign up and login Form
        </h1>
     </div>
  </div>

  <div id="content1" class="popup-effect">
           <div class="popup">
              <!--login form-->
              <div class="letter-w3ls">
                 <form action="UserRegisterservlet" method="get">
                    <div class="form-left-to-w3l">
                       <input type="text" name="name" placeholder="Username" >
                    </div>
                    <div class="form-left-to-w3l">
                       <input type="text" name="phone" placeholder="Phone" >
                    </div>
                    <div class="form-left-to-w3l">
                       <input type="email" name="email" placeholder="Email" >
                    </div>
                    <div class="form-left-to-w3l">
                       <input type="password" name="password" placeholder="Password" >
                    </div>
                    <div class="form-left-to-w3l margin-zero">
                       <input type="password" name="password" placeholder="Confirm Password" >
                    </div>
                    <div class="btnn">
                       <button type="submit">Sign Up</button>
                       <br>
                    </div>
                 </form>
                 <div class="clear"></div>
              </div>
              <!--//login form-->
              <a class="close" href="#">&times;</a>
           </div>
        </div>
  <footer class="bottem-wthree-footer">

  </footer>
</body>
</html>

运行界面（输入用户名和密码，通过和数据库中的文件比对后返回结果。登陆成功则到显示页面，失败则重新返回到这个页面并弹窗显示ERROR）

先写这些把，后面的功能下一次在写(●ˇ∀ˇ●)