初次Java web项目的建立以及与数据库的连接

题目要求：

1登录账号：要求由6到12位字母、数字、下划线组成，只有字母可以开头；（1分）

2登录密码：要求显示“• ”或“*”表示输入位数，密码要求八位以上字母、数字组成。（1分）

3性别：要求用单选框或下拉框实现，选项只有“男”或“女”；（1分）

4学号：要求八位数字组成，前四位为“2018”开头，输入自己学号；（1分）

5姓名：输入自己的姓名；

5电子邮箱：要求判断正确格式xxxx@xxxx.xxxx；（1分）

6点击“添加”按钮，将学生个人信息存储到数据库中。（3分）

7可以演示连接上数据库。（2分）

思路：

先建立一个web项目，制作网页。然后在src目录下建立四个包。

第一个包，bean包，包括userbean类，代码如下，主要进行，数据的声明，和get()、set()、有参构造方法和无参构造方法

 package com.user.bean;

 public class UserBean {
     private String id;
     private String pass;
     private String sex;
     private String name;
     private String xue;
     private String e_mail;
     private String yuan;
     private String xi;
     private String ban;
     private String nian;
     private String di;
     private String bei;

     public String getId() {
         return id;
     }
     public void setId(String id) {
         this.id = id;
     }
     public String getPass() {
         return pass;
     }
     public void setPass(String pass) {
         this.pass = pass;
     }
     public String getSex() {
         return sex;
     }
     public void setSex(String sex) {
         this.sex = sex;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public String getXue() {
         return xue;
     }
     public void setXue(String xue) {
         this.xue = xue;
     }
     public String getE_mail() {
         return e_mail;
     }
     public void setE_mail(String e_mail) {
         this.e_mail = e_mail;
     }
     public String getYuan() {
         return yuan;
     }
     public void setYuan(String yuan) {
         this.yuan = yuan;
     }
     public String getXi() {
         return xi;
     }
     public void setXi(String xi) {
         this.xi = xi;
     }
     public String getBan() {
         return ban;
     }
     public void setBan(String ban) {
         this.ban = ban;
     }
     public String getNian() {
         return nian;
     }
     public void setNian(String nian) {
         this.nian = nian;
     }
     public String getDi() {
         return di;
     }
     public void setDi(String di) {
         this.di = di;
     }
     public String getBei() {
         return bei;
     }
     public void setBei(String bei) {
         this.bei = bei;
     }

     public UserBean() {}
     public UserBean(String Id,String Pass,String Sex,String Name,String Xue,String E_mail,String Yuan,String Xi,String Ban,String Nian,String Di,String Bei)
     {
         this.id=Id;
         this.pass=Pass;
         this.sex=Sex;
         this.name=Name;
         this.xue=Xue;
         this.e_mail=E_mail;
         this.yuan=Yuan;
         this.xi=Xi;
         this.ban=Ban;
         this.nian=Nian;
         this.di=Di;
         this.bei=Bei;
     }
 }

第二个包，dao层封装方法

 package com.user.dao;
 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.Statement;
 import java.util.ArrayList;
 import java.util.List;
 import com.user.bean.UserBean;
 import com.util.DBUtil;

 public class UserDao {
     public static void main(String[] args) {
 //        List<UserBean> users=new ArrayList<UserBean>();
 //        UserBean user=new UserBean();
 //        user=list("1");
 //        System.out.println(user.getId_zaibu());
 //        checkLogin("root","root");

     }

     /**
      * 注册
      * @param userBean
      */
     public void reg(UserBean userBean) {
         String sql = "insert into login(Id,Pass,Sex,Name,Xue,E_mail,Yuan,Xi,Ban,Nian,Di,Bei) values('"+userBean.getId()+"','"+userBean.getPass()+"','"+userBean.getSex()+"','"+userBean.getName()+"','"+userBean.getXue()+"','"+userBean.getE_mail()+"','"+userBean.getYuan()+"','"+userBean.getXi()+"','"+userBean.getBan()+"','"+userBean.getNian()+"','"+userBean.getDi()+"','"+userBean.getBei()+"')";
         Connection conn = DBUtil.getConn();
         Statement state = null;
         try {
             state = conn.createStatement();
             state.executeUpdate(sql);
         } catch (Exception e) {
             e.printStackTrace();
         }finally{
             DBUtil.close(state, conn);
         }
     }
 }

第三个包，servlet层，连接页面和数据库；

package com.user.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.user.bean.UserBean;
import com.user.dao.UserDao;

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

    /**
     * @see HttpServlet#HttpServlet()
     */
    public LoginServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // TODO Auto-generated method stub
//        response.getWriter().append("Served at: ").append(request.getContextPath());
        req.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=utf-8");
        HttpSession session=req.getSession();

        String Id = req.getParameter("Id");
        String Pass = req.getParameter("Pass");
        String Name = req.getParameter("Name");
        String Sex = req.getParameter("Sex");
        String Xue = req.getParameter("Xue");
        String Di = req.getParameter("Di");
        String Yuan = req.getParameter("Yuan");
        String E_mail = req.getParameter("E_mail");
        String Xi = req.getParameter("Xi");
        String Ban = req.getParameter("Ban");
        String Nian = req.getParameter("Nian");
        String Bei = req.getParameter("Bei");

        UserDao adminDao = new UserDao();
        UserBean a=new UserBean();
        a.setId(Id);
        a.setPass(Pass);
        a.setName(Name);
        a.setXue(Xue);
        a.setSex(Sex);
        a.setDi(Di);
        a.setXi(Xi);
        a.setBan(Ban);
        a.setNian(Nian);
        a.setBei(Bei);
        a.setE_mail(E_mail);
        a.setYuan(Yuan);
        adminDao.reg(a);
        resp.sendRedirect(req.getContextPath() + "/Sussess.jsp");
    }
    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

第四个包，封装工具层

 package com.util;

 public class Constants {
     public static final String SESSION_LOGIN_BEAN="loginbean";

 }

 package com.util;

 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;

 /**
  * 数据库的工具类
  * @author zm
  *
  */
 public class DBUtil {
     //eshop为数据库名称，db_user为数据库用户名db_password为数据库密码
 public static String db_url ="jdbc:mysql://localhost:3306/daer?&useSSL=false&serverTimezone=UTC";
     public static String db_user = "root";
     public static String db_password = "root";
     public static Connection getConn() {
         Connection conn = null;
         try {
             Class.forName("com.mysql.jdbc.Driver");
             conn = DriverManager.getConnection(db_url, db_user, db_password);
         } catch (Exception e) {
             e.printStackTrace();
         }
         return conn;
     }

     public static void close(Statement state, Connection conn) {
         if(state!=null) {
             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) {
             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();
             }
         }
     }
 }

package com.util;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

public class StringUtil {

    /**
     * @param str
     * @return
     */
    public static int StringToInt(String str) {
        int result = 0;
        try {
            result = Integer.parseInt(str);
        } catch (NumberFormatException e) {
            result = 0;
            //e.printStackTrace();
        }
        return result;
    }
    /**
     * @param length
     * @return
     */
    public static String getRandomString(int length) {
        String base = "abcdefghijklmnopqrstuvwxyz0123456789";
        Random random = new Random();
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < length; i++) {
            int number = random.nextInt(base.length());
            sb.append(base.charAt(number));
        }
        return sb.toString();
     }

    public static List<String> splitProperties (String properties){
        List<String> options = new ArrayList<String>();
        String option = null;
        String[] strings = properties.split(",");
        for (String string : strings) {
            if(!"0".equals(string)){
                option = string.charAt(3)+"";
                options.add(option);

            }
        }
        return options;

    }
    /**
     * @param str
     * @return
     */
    public static float strToFlo(String str) {
        float i = 0;
        try {
            i = Integer.parseInt(str);
        } catch (Exception e) {
        }
        return i;
    }
}

网页界面：

 <%@ 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>登录</title>
 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <style type="text/css">
         .code
         {
             background-image:url(code.jpg);
             font-family:Arial;
             font-style:italic;
             color:Red;
             border:0;
             padding:2px 3px;
             letter-spacing:3px;
             font-weight:bolder;
         }
         .unchanged
         {
             border:0;
         }
     </style>
     <script type="text/javascript">
     function validate()
     {

         var Id=document.forms["myForm"]["Id"].value;
         var reg= /^[A-Za-z0-9]{6,12}$/;

         if(!Id.match(reg))
             {
             alert("登陆账号必须由六到十二英文字符或数字组成，以英文字母开头");
             return false;
             }
         var Pass=document.forms["myForm"]["Pass"].value;
          reg= /^[A-Za-z0-9]{8,20}$/;
          if(!Pass.match(reg))
          {
          alert("密码必须由八位以上英文字符或数字组成");
          return false;
          }

          var Xue=document.forms["myForm"]["Xue"].value;
          reg= /^[0-9]{8}$/;
          if(!Xue.match(reg))
          {
          alert("要求八位数字组成，前四位为“2018”开头");
          return false;
          }
          var E_mail=document.forms["myForm"]["E_mail"].value;
          reg=/^([0-9A-Za-z\-_\.]+)@([0-9a-z]+\.[a-z]{2,3}(\.[a-z]{2})?)$/g;
              if(!E_mail.match(reg))
                  {
                  alert("邮箱请输入正确格式");
                  return false;
                  }
     }

     </script>
 </head>
 <body >
             <form name="myForm" action="${pageContext.request.contextPath}/LoginServlet" onsubmit="return validate()" method="post" >
                     <label>登陆账号</label>
                         <input  name="Id" type="text" value="" /><br>
                     <label >登陆密码</label>
                         <input type="Pass" name="Pass" ><br>
                     <label >性别</label>
                     <input name="Sex" type="radio" value="女">女&nbsp;&nbsp;
                     <input name="Sex" type="radio" value="男">男<br>
                     <label >姓名</label>
                         <input  name="Name" type="text" value="" /><br>
                     <label >学号</label>
                         <input  name="Xue" type="text" value="" /><br>
                     <label >电子邮件</label>
                         <input  name="E_mail" type="text" value="" /><br>
                     <label >所在学院</label>
                         <input  name="Yuan" type="text" value="" /><br>
                     <label >所在系</label>
                         <input  name="Xi" type="text" value="" /><br>
                     <label >所在班级</label>
                         <input  name="Ban" type="text" value="" /><br>
                     <label >入学年份（届）</label>
                         <select name="Nian">
                         <%for(int i=1998;i<2020;i++){ %>
                         <option value="<%=i%>"><%=i %></option>
                         <%} %>
                         </select><br>
                     <label >生源地</label>
                         <input  name="Di" type="textarea" value="" /><br>
                     <label >备注</label>
                         <textarea name="Bei" rows="20" cols="20"></textarea><br>
                         <button type="submit">注册</button>
                         <button type="reset" >重置</button>
             </form>
 </body>
 </html>

<%@ 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>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<script type="text/javascript">
alert("成功！");
</script>
</body>
</html>

sql语句：

 /*
 Navicat MySQL Data Transfer

 Source Server         : MySQL
 Source Server Version : 80015
 Source Host           : localhost:3306
 Source Database       : daer

 Target Server Type    : MYSQL
 Target Server Version : 80015
 File Encoding         : 65001

 Date: 2019-10-21 15:21:01
 */

 SET FOREIGN_KEY_CHECKS=0;

 -- ----------------------------
 -- Table structure for login
 -- ----------------------------
 DROP TABLE IF EXISTS `login`;
 CREATE TABLE `login` (
   `Id` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
   `Pass` varchar(255) DEFAULT NULL,
   `Sex` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
   `Name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
   `Xue` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
   `E_mail` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
   `Yuan` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL,
   `Xi` varchar(255) DEFAULT NULL,
   `Ban` varchar(255) DEFAULT NULL,
   `Nian` varchar(255) DEFAULT NULL,
   `Di` varchar(255) DEFAULT NULL,
   `Bei` varchar(255) DEFAULT NULL
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

 -- ----------------------------
 -- Records of login
 -- ----------------------------

运行结果如下：

 

以下分别是条件不满足，和最后满足添加成功以及数据库保存的内容

体会：以后做大项目的时候，尤其要注意分层完成，条理清晰，哪里出了问题可以去改，而且做完一个小类就要去测试，是否正确，不要等到所有内容全部完成，因为全部完成的话，代码量很大，出问题了你也不知道如何去改，很费时间，相反，保证每个小项目都没有错，那么大的错误也不会有。初次做java web项目有些不熟悉，连数据库也不太会，只有多多练习，别人的代码不是你的代码，别人告诉你的代码，你不一定会，同样，从网上找到的模板你不一定会，因此一定要自己写代码，写明白，这样才是自己真的会了，否则，你这次找别人要的代码，下次也还会是，你永远也不会进步，就像是愚公一样，哪怕自己一次弄不明白，可以千次万次，这样也会进步，可就是不能去复制粘贴，别人的代码，一知半解或者压根都不明白，这才是最可怕的，表面上很厉害，但是真拿出来，自己又是不会，因此，要培养自己独立动手思考还有改错的能力