老图搬砖day09——Servlet+mySQL+JSP完成简单页面登陆注册

本文介绍如何使用Servlet、MySQL数据库和JSP创建一个简单的登录注册页面。用户输入信息通过Servlet验证,错误信息实时反馈。注册后信息存储至数据库,成功登录后展示所有数据。

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这里写自定义目录标题

题目描述

使用MySQL数据库

建立数据库名称:jsp

建立数据表:inf(id,name,pwd,age,gender)

create table inf
(id int primary key auto_increment,
 name char(20) not null,
 pwd char(20) not null,
 age int not null,
 gender char(2) not null) default charset=utf8;

用户登录,输入用户名与密码(如图一)
用户名与密码需要到数据库验证,如果验证错误,提示错误信息(如图二
),点击“注册”,跳转到“注册”页面(如图四),把用户名,密码,年龄,性别 这些信息,添加到数据库,点击,“返回登录”,回到登录页面,重新输入用户名,密码,登录成功后,进入“显示数据页面”,把数据表中的所有信息显示出来(如图三 )
在这里插入图片描述
在这里插入图片描述
在这里插入图片描述
在这里插入图片描述

代码

使用myEclipse,建立与mySQL之间的连接
首先在Navicat 中新建数据库 jsp,新建表如下:
在这里插入图片描述
建立连接:

package com.sy.util;

import java.sql.*;

public class DBUtil {
	public static Connection getConnection(){
		
		Connection conn = null;  
		try {
			
			Class.forName("com.mysql.jdbc.Driver");
		} catch (ClassNotFoundException e) {
			
			e.printStackTrace();
			System.out.println("未找到驱动类!");
		}
		
		try {
			String url = "jdbc:mysql://localhost:3306/jsp";
			conn = DriverManager.getConnection(url, "root","123456");
		} catch (SQLException e) {
			
			e.printStackTrace();
			System.out.println("数据库服务器异常,数据连接错误!");
		}
		
		return conn;
	}
	
	public static void closeAll(ResultSet rs,Statement stmt,PreparedStatement pstmt,Connection conn){
		
		try {
			if(rs != null){
				rs.close();
			} 
			
			if(stmt != null){
				stmt.close();
			} 
			if(pstmt != null){
				pstmt.close();
			}
			if(conn != null){
				conn.close();
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	
	public static void main(String[] args){
		Connection conn = DBUtil.getConnection();
		System.out.println(conn != null ? "连接成功!" : "连接失败!");
	}
	

}

实体类:

package com.sy.entity;

public class Inf {
	private int id;
	private String name;
	private String pwd;
	private int age;
	private String gender;
	
	public Inf(){
		
	}
public Inf(String name, String pwd,int age,String gender) {
		
		super();
		this.name = name;
		this.pwd = pwd;
		this.age = age;
		this.gender = gender;
	}
	public Inf(int id, String name, String pwd,int age,String gender) {
		
		this.id = id;
		this.name = name;
		this.pwd = pwd;
		this.age = age;
		this.gender = gender;
	}
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPwd() {
		return pwd;
	}
	public void setPwd(String pwd) {
		this.pwd = pwd;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public String getGender() {
		return gender;
	}
	public void setGender(String gender) {
		this.gender = gender;
	}
	public String toString(){
		return this.id+"\t"+this.name+"\t"+this.pwd+"\t"+this.age+"\t"+this.gender;
	}
}

Dao:

package com.sy.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import com.sy.util.*;
import com.sy.entity.*;

public class InfDao {
	private static Connection conn = null;
	private static Statement stmt = null;
	private static PreparedStatement pstmt = null;
	private static ResultSet rs = null;
	
	public Inf queryByName(String name){
		Inf inf=null;
		try {
			String sql="select * from inf where name=?";
			conn = DBUtil.getConnection();
			pstmt = conn.prepareStatement(sql);
			pstmt.setString(1, name);
		//	pstmt.setString(2, password);
			rs = pstmt.executeQuery();
			if(rs.next()){
				inf = new Inf();
				inf.setId(rs.getInt(1));
				inf.setName(rs.getString(2));
				inf.setPwd(rs.getString(3));
				inf.setAge(rs.getInt(4));
				inf.setGender(rs.getString(5));
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		}finally{
			DBUtil.closeAll(rs, null, pstmt, conn);
		}
		return inf;
		
	}
	
	public List<Inf> queryInfList(){
		List<Inf> inflist = new ArrayList<Inf>();
		try {
			String sql ="select * from inf";
			conn = DBUtil.getConnection();
			stmt = conn.createStatement();
			rs = stmt.executeQuery(sql);
			while(rs.next()) {
				Inf inf = new Inf();
				inf = new Inf();
				inf.setId(rs.getInt(1));
				inf.setName(rs.getString(2));
				inf.setPwd(rs.getString(3));
				inf.setAge(rs.getInt(4));
				inf.setGender(rs.getString(5));
				inflist.add(inf);
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		}finally{
			DBUtil.closeAll(rs, stmt, null, conn);
		}
		return inflist;
	}
	public static boolean addInf(Inf inf) {
		
		try {
			String sql = "insert into inf(name,pwd,age,gender) values(?,?,?,?)";
			conn = DBUtil.getConnection();
			pstmt = conn.prepareStatement(sql);
			pstmt.setString(1, inf.getName());
			pstmt.setString(2, inf.getPwd());
			pstmt.setInt(3, inf.getAge());
			pstmt.setString(4, inf.getGender());
			int rows=pstmt.executeUpdate();
			if(rows>0){
				return true;
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			DBUtil.closeAll(rs,stmt,null,conn);
		}
	
		return false;
	}

}

登陆界面jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
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>登陆界面</title>
    <script type="text/javascript">
    	function confirm(){
    		var username = document.log.user.value;
    		var password = document.log.password.value;
    		if(username==""){
    			alert("用户名不能为空!");
    			return false;
    		}
    		if(password==""){
    			alert("密码不能为空!");
    			return false;
    		}
    	}
    </script>
	

  </head>
  
  <body>
  	<h1>登陆界面</h1>
    <form name="log" action="Task2" method="post" onsubmit="return confirm()">
    <table>
    	<tr><td>用户名</td><td><input type="text" name="user"></td></tr>
    	<tr><td>密码</td><td><input type="password" name="password"></td></tr>
    	<tr><td><input type="submit" value="登陆" > <input type="button" value="注册" onclick="javascript:location.href='<%=basePath%>reg.jsp'"/></td>
    	<td><div id="error" name="error" style="display:inline;font-size:15px;color:red;">
    	<%= request.getAttribute("error")==null? "" : request.getAttribute("error")%></div></td>
  	</table>
    </form>
  </body>
</html>

登陆界面servlet

package com.sy.servlet;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

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

import com.sy.dao.*;
import com.sy.entity.*;

public class MyServlet extends HttpServlet{

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		this.doPost(request, response);
	}

	@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		request.setCharacterEncoding("utf-8");
		response.setContentType("text/html;charset=UTF-8");
		String name = request.getParameter("user");
		String password = request.getParameter("password");
		
		InfDao infDao = new InfDao();
		Inf inf = infDao.queryByName(name);
		if(inf!= null){
			if(inf.getPwd()==password){
			List<Inf> list =infDao.queryInfList();
			request.setAttribute("list", list);
			request.getRequestDispatcher("/list.jsp").forward(request, response);
			}
			else{
				request.setAttribute("error","用户名或密码错误!");
				request.getRequestDispatcher("/logIn.jsp").forward(request, response);								
			}
		}else{
			request.setAttribute("error","用户名或密码错误!");
			request.getRequestDispatcher("/logIn.jsp").forward(request, response);
		}
	}
	
}

展示所有数据的list.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>list</title>
    <style type="text/css">
		table{
			border: 1px ;
			border-color: yellow;			
		}    
    </style>

  </head>
  
  <body>
  
    <table border="1" cellspacing="0">
    
    	<tr>
			<th>编号</th>
			<th>姓名</th>
			<th>密码</th>
			<th>年龄</th>
			<th>性别</th>
		</tr>
		<c:forEach items="${list}" var="usr">
    	<tr align="center"><td>${usr.id}</td><td>${usr.name}</td><td>${usr.pwd}</td><td>${usr.age}</td><td>${usr.gender}</td>
        </tr>          
	</c:forEach>
    
    </table>
  </body>
</html>

注册界面jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>


<%
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>注册界面</title>
    <script type="text/javascript">
    	function validForm(){
    		var username = document.reg.user.value;
    		var password = document.reg.password.value;
    		var age = document.reg.age.value;
    		var gender = document.reg.gender.value;
    		if(username==""){
    			alert("用户名不能为空!");
    			return false;
    		}
    		if(password==""){
    			alert("密码不能为空!");
    			return false;
    		}
    		
    		if(!/^\w{3}$/.test(password)){
    			alert("请输入三位密码!");
    			return false;
    		}
    		if(age=="0"){
    			alert("请选择正确的年龄!");
    			return false;
    		}
    	
    	}
    </script>


  </head>
  
  <body>
    <h1>注册界面</h1>
    <form name="reg" action="Register" method="post" onsubmit="return validForm()">
    <table>
    	<tr><td>用户名</td><td><input type="text" name="user"></td></tr>
    	<tr><td>密码</td><td><input type="password" name="password"></td></tr>
    	<tr><td>年龄</td><td><select name="age">
    							<option value=0>请选择年龄</option>
    							<option value=20>21</option>
    							<option value=22>22</option>
    							<option value=23>23</option>
    							<option value=24>24</option>
    							<option value=25>25</option>
    							<option value=26>26</option>
    							<option value=27>27</option>
    							<option value=28>28</option>
    							<option value=29>29</option>
    							<option value=30>30</option>
    							<option value=31>31</option>
    							<option value=32>32</option>
    							<option value=33>33</option>
    							<option value=34>34</option>
    							<option value=35>35</option>
    							<option value=36>36</option>
    							<option value=37>37</option>
    							<option value=38>38</option>
    							<option value=39>39</option>
    							<option value=40>40</option>
    							<option value=41>41</option>
    							<option value=42>42</option>
    							<option value=43>43</option>
    							<option value=44>44</option>
    							<option value=45>45</option>
    					   </select></td></tr>
    	<tr><td>性别</td><td>
						<input type="radio" name="gender" checked="checked" value="男"><input type="radio" name="gender" value="女"></td></tr>				   
    	<tr><td><input type="submit" value="注册" ></td><td><input type="button" value="返回登陆" onclick="javascript:location.href='<%=basePath%>logIn.jsp'"/></td></tr>
    	<tr colspan="2"><div id="meg" name="meg" style="display:inline;font-size:15px;color:red;">&nbsp;
    	<%= request.getAttribute("meg")==null? "" : request.getAttribute("meg")%></div></tr>
    	</table>
    	
    	
    </form>
  </body>
</html>

注册的servlet

package com.sy.servlet;

import java.io.IOException;
import java.io.PrintWriter;

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

import com.sy.dao.InfDao;
import com.sy.entity.Inf;

public class Reg extends HttpServlet {

	

	
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		this.doPost(request, response);
	}

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

		request.setCharacterEncoding("utf-8");
		String name = request.getParameter("user");
		String password = request.getParameter("password");
		int age = Integer.valueOf(request.getParameter("age"));
		String gender = request.getParameter("gender");
		String meg = null;
		Inf inf = new Inf(name,password,age,gender);
		boolean flag = InfDao.addInf(inf);
		if(flag){
			meg = "注册成功!";
			request.setAttribute("meg",meg);
			request.getRequestDispatcher("/reg.jsp").forward(request, response);
		}else{
			meg = "注册失败!";
			request.setAttribute("meg",meg);
			request.getRequestDispatcher("/reg.jsp").forward(request, response);
		}
	}

	
}

其实这样子有点繁琐,可以用一个servlet来响应多个jsp的请求,但是老师讲的时候我差不多已经写完了,所以最后没有修改。
web.index

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
	xmlns="http://java.sun.com/xml/ns/javaee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <display-name></display-name>	
    <servlet>
	<servlet-name>MyServlet</servlet-name>
	<servlet-class>com.sy.servlet.MyServlet</servlet-class>  
  </servlet>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>Reg</servlet-name>
    <servlet-class>com.sy.servlet.Reg</servlet-class>
  </servlet>

  
  <servlet-mapping>
  	<servlet-name>MyServlet</servlet-name>
  	<url-pattern>/Task2</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>Reg</servlet-name>
    <url-pattern>/Register</url-pattern>
  </servlet-mapping>
  
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

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