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java jsp+servlet+mysql实现登录网页设计

时间：2022-03-14 02:39

涉及下面几个文件：

1，登录页面 login.jsp

2，成功跳转页面 success.jsp

3，失败跳转页面 fail.jsp

4，servlet 处理类 LoginTestServlet.java

5，配置文件 web.xml

--------------------------------------------- 依次看代码 --------------------------------------------

LoginTestServlet.java 内容

package com.test;

import java.io.IOException;
import java.sql.DriverManager;
import java.sql.ResultSet;

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.mysql.jdbc.Connection;
import com.mysql.jdbc.Statement;

/**
 * Servlet implementation class LoginTestServlet
 */
@WebServlet("/LoginTestServlet")
public class LoginTestServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public LoginTestServlet() {
        super();
        
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		response.setContentType("text/heml;charset=gb2312");
		request.setCharacterEncoding("gb2312");
		
		String result = "";
	
		String username = request.getParameter("username");
		String psw = request.getParameter("password");
		
		if(username == "" || username == null || username.length()>20){
			try {
				result = "请输入用户名（不能超过20个字符）";
				request.setAttribute("message", result);
				response.sendRedirect("login.jsp");
				return;
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		
		if(psw == "" || psw == null || psw.length() > 20){
			try {
				result = "请输入密码（不能超过20个字符）";
				request.setAttribute("message", result);
				response.sendRedirect("login.jsp");
				return;
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		
		//登记JDBC驱动程序
		try {
			Class.forName("com.mysql.jdbc.Driver");
		} catch (Exception e) {
			System.out.print("Class Not Found Exception");
		}
		
		//链接URL
		String url = "jdbc:mysql://localhost:3306/demo";
		Connection conn = null;
		Statement stmt = null;
		ResultSet rs = null;
		
		try {
			conn = (Connection) DriverManager.getConnection(url,"root","root");
			stmt = (Statement) conn.createStatement();
			
			String sql = "select * from userInfo where username='"+username+"' and userpsw= '"+psw+"'";
			rs = stmt.executeQuery(sql);
		} catch (Exception e) {
			e.printStackTrace();
		}
		
	HttpSession session = request.getSession();
	session.setAttribute("username", username);
		
	try {
		if(rs.next()){
		    session.setAttribute("age",rs.getString("age")) ;
		    session.setAttribute("sex",rs.getString("sex")) ;
		    session.setAttribute("weight",rs.getString("weight")) ;
		    response.sendRedirect("success.jsp") ;
		    return;
		}else{
		    session.setAttribute("message", "用户名或密码不匹配。");
		    response.sendRedirect("fail.jsp") ;
		    return;
		}
		
	} catch (Exception e) {
		e.printStackTrace();
	}
	}

}

<%@ 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>用户登录</title>
</head>
<body>
 	<form method="POST" name="frmLogin" action="LoginTestServlet">
 		<h1 align="center">用户登录</h1>
 		<center>
 			<table border="1">
 				<tr>
 					<td>用户名：</td>
 					<td>
 					    <input type="text" name="username" value="" size="20" maxlength="20" onfocus="if (this.value=='Your name')  this.value='';" />
 					</td>
 				</tr>
 				<tr>
 					<td>密  码</td>
 					<td>
 						<input type="password" name="password" value="" size="20" maxlength="20" onfocus="if(this.value=='Your Password') this.value='';">
 					</td>
 				</tr>
 				<tr>
 					<td>
 						<input type="submit" name="Submit" value=" 提交" onclick="return validateLogin()">
 					</td>
 					<td>
 					    <input type="reset" name="Reset" value="重置" />
 					</td>
 				</tr>
 			</table>
 		</center>
 	</form>
 	
 	<script type="text/javascript">
 			   function validateLogin(){
 				 var sUserName = document.frmLogin.username.value;
 				 var sPassword = document.frmLogin.psssword.value;
 			    if (sUserName ==""){
 			     alert("请输入用户名!");
 			     return false ;
 			    }
 			    
 			    if (sPassword ==""){
 			     alert("请输入密码!");
 			     return false ;
 			    }
 		}
 	</script>
</body>
</html>

success.jsp 内容

<%@ 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>
<%
   String userName = (String)session.getAttribute("username") ;
   String age = (String)session.getAttribute("age") ;
   String weight = (String)session.getAttribute("weight") ;
   String sex = (String)session.getAttribute("sex") ;
   System.out.println("性别：A" + sex +"A")  ;
   if (sex.trim().equals("M")) {
    sex ="男" ;
   }else{
    sex = "女" ;
   }
  %>
  <div align="center">
   <%=userName %>
   欢迎您，登陆成功！<br />
   <font color="blue">登陆用户信息：</font>
   <table border =1 >
    <tr>
     <td> 姓名： </td>
     <td>  <%=userName %>  </td>
    </tr>
    <tr>
     <td> 年龄： </td>
     <td>  <%=age %>  </td>
    </tr>
    <tr>
     <td> 体重： </td>
     <td>  <%=weight %> kg </td>
    </tr>
    <tr>
     <td> 性别： </td>
     <td>  <%=sex %>  </td>
    </tr>
   </table>
   <a href="login.jsp">返回</a>
  </div>
</body>
</html>

fail.jsp 内容

<%@ 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>
	<%
		String userName = (String) session.getAttribute("username");
		String msg = (String) session.getAttribute("message");
	%>
	<div align="center">
		<%=userName%>
		对不起，登陆失败！<br /> <font color="red">原因： </font>
		<%=msg%>
		<br /> <br /> 5秒后将返回登陆界面。
	</div>

	<%
		response.setHeader("Refresh", "5;URL=/webDemo/login.jsp");
	%>
</body>
</html>

-------------------------------------------------------配置数据库------------------------------------------------------

mysql数据库中需要创建数据库demo，其中创建表userInfo 创建表语句为：
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>webDemo</display-name> <welcome-file-list> <welcome-file>index.html</welcome-file> <welcome-file>index.htm</welcome-file> <welcome-file>index.jsp</welcome-file> <welcome-file>default.html</welcome-file> <welcome-file>default.htm</welcome-file> <welcome-file>default.jsp</welcome-file> </welcome-file-list>

	<servlet>
		<servlet-name>LoginTestServlet</servlet-name>
		<servlet-class>com.test.LoginTestServlet</servlet-class>
	</servlet>
	
	<servlet-mapping>
		<servlet-name>LoginTestServlet</servlet-name>
		<url-pattern>/loginTestServlet</url-pattern>
	</servlet-mapping>
</web-app>