java jsp+servlet实现登录网页设计
java jsp+servlet实现登录网页设计
|
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> </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> //-------------------------------------------------------------------------------------------------------------------- |