您的位置：首页 > 编程语言 > Java开发

java jsp+servlet实现登录网页设计

2015-09-22 10:58 736 查看

java jsp+servlet实现登录网页设计

[align=center][/align]这次涉及到四个文件:
登录页面:login.jsp登录成功欢迎页面:success.jsp
登录失败页面:fail.jsp
Servlet处理文件:LoginServlet.java其实还涉及到一个文件:web.xml,这个后面再说:下面分别介绍这几个文件:
//--------------------------------------------------------------------------------------------------------------------
LoginServlet.java 内容：

package org.cai.servlet ;
import java.sql.* ;
import java.io.* ;
import javax.servlet.http.* ;
import javax.servlet.* ;
public class LoginServlet extends HttpServlet implements Servlet{
public LoginServlet(){
}

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

}
// protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
// System.out.println("-------------------------") ;
// doPost(request, response) ;
// }
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
response.setContentType("text/html;charset=gb2312") ;
request.setCharacterEncoding("gb2312") ;
String result = "" ;
//获取用户名
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") ;
}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") ;
}catch(Exception e){
e.printStackTrace() ;
}
}

//登记JDBC驱动程序
try{
Class.forName("org.gjt.mm.mysql.Driver") ;
}catch(ClassNotFoundException e){
e.printStackTrace() ;
System.out.println("Class Not Found Exception . ") ;
}
//连接URL
String url ="jdbc:mysql://localhost:3306/learnJSP" ;
Connection conn = null ;
Statement stmt = null ;
ResultSet rs = null ;

try{
conn = DriverManager.getConnection(url, "root", "root") ;
stmt = conn.createStatement() ;
//SQL语句
String sql ="select * from userInfo where username='"+username+"' and userpsw= '"+psw+"'" ;
rs = stmt.executeQuery(sql) ;//返回查询结果
}catch(SQLException e){
e.printStackTrace() ;
}
HttpSession session = request.getSession() ;
session.setAttribute("username", username) ;
//System.out.println("+++++++++++++++++++++++"+ username) ;
try{
if (rs.next()){ //如果记录集非空，表明有匹配的用户名和密码，登陆成功
// 登录成功后将username设置为session变量的username
// 这样在后面就可以通过 session.getAttribute("username") 来获取用户名，
// 同时这样还可以作为用户登录与否的判断依据
session.setAttribute("age",rs.getString("age")) ;
session.setAttribute("sex",rs.getString("sex")) ;
session.setAttribute("weight",rs.getString("weight")) ;
response.sendRedirect("success.jsp") ;
}else{
session.setAttribute("message", "用户名或密码不匹配。");
response.sendRedirect("fail.jsp") ;
}
}catch(SQLException e){
e.printStackTrace() ;
}
}

private static final long serialVersionUID = 1L;
}

//--------------------------------------------------------------------------------------------------------------------
login.jsp内容：

<%@ page language="java" contentType="text/html;charset=gb2312"%>
<html>
<head>
<title>登陆</title>
</head>
<body>
<form method="POST" name="frmLogin" action="LoginServlet">
<h1 align="center">用户登录</h1><br />
<center>
<table border=1>
<tr>
<td>用户名：</td>
<td>
<input type="text" name="username" value="Your name" 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="Your password" 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 language="javascript">
function validateLogin(){
var sUserName = document.frmLogin.username.value ;
var sPassword = document.frmLogin.password.value ;
if ((sUserName =="") || (sUserName=="Your name")){
alert("请输入用户名!");
return false ;
}

if ((sPassword =="") || (sPassword=="Your password")){
alert("请输入密码!");
return false ;
}
}
</script>
</body>
</html>
//--------------------------------------------------------------------------------------------------------------------
success.jsp 内容:

<%@ page language="java" contentType="text/html;charset=gb2312" pageEncoding ="gb2312"%>
<html>
<head>
<title>欢迎</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 </>
</tr>
<tr>
<td> 性别： </td>
<td>  <%=sex %>  </>
</tr>
</table>
<a href="login.jsp">返回</a>
</div>
</body>
</html>
//--------------------------------------------------------------------------------------------------------------------
fail.jsp 内容：

<%@ page language="java" contentType="text/html;charset=gb2312" pageEncoding ="gb2312"%>
<html>
<head>
<title>登陆失败</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=/learnJSP/login.jsp");
%>
</body>
</html>
//--------------------------------------------------------------------------------------------------------------------
mysql数据库中需要创建数据库learnJSP，其中创建表userInfo 创建表语句为：

create database learnJSP ;
use learnJSP
create table userInfo(id int not null primary key,username char(20) not null,userpsw char(20) ,age int ,weight int ,sex enum('M','F')) ;

需要把连接mysql的jar包放到项目的lib目录中
//--------------------------------------------------------------------------------------------------------------------
web.xml 内容：

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file> //index改为login ?
</welcome-file-list>

<servlet>
<servlet-name>
LoginServlet
</servlet-name>
<servlet-class>
org.cai.servlet.LoginServlet
</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>

</web-app>

http://blog.csdn.net/cai5/article/details/7266460

内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理

标签：

相关文章推荐

新的分享

章节导航