這次涉及到四個文件:
登錄頁面:login.html
登錄成功歡迎頁面:login_success.jsp
登錄失敗頁面:login_failure.jsp
Servlet處理文件:LoginServlet.java
其實還涉及到一個文件:web.xml,這個后面再說:
下面分別介紹這幾個文件:
登錄頁面:login.html
|
<!-- 該Login頁面是一個簡單的登錄界面 -->
<!--
該JSP程序是用來測試與MySQL數據庫的連接，
需要一個數據庫：LearnJSP，和其中一個表：userinfo
表中有兩個字段分別為：UserName varchar (20) not null,UserPwd varchar (20) not null
-->
<
html
>
??<head>
????<title>登錄</title>
????<meta http-equiv="content-type"content="text/html; charset=UTF-8">
????<meta http-equiv="Content-Language"content="ch-cn">
??</head>
??<body>
<!-- Form 用來提取用戶填入并提交的信息-->
<formmethod="post"name="frmLogin"action="LoginServlet">
???<h1align="center">用戶登錄</h1><br>
???<divalign="center">用戶名：
??????<inputtype="text"name="txtUserName"value="Your name"
???????size="20"maxlength="20"
???????onfocus="if(this.value=='Your name')this.value='';"><br>密碼：
??????<inputtype="password"name="txtPassword"value="Your password"
???????size="20"maxlength="20"
???????onfocus="if(this.value=='Your password')this.value='';"><br>
??????<inputtype="submit"name="Submit" value="提交"onClick="validateLogin();">
???????
??????<inputtype="reset"name="Reset"value="重置"><br>
???</div>
</form>
<!-- javaScript 函數 validateLogin(),用來驗證用戶名和密碼是否為空 -->
????<scriptlanguage="javaScript">
????? function validateLogin()
?????{
??????var sUserName = document.frmLogin.txtUserName.value;
??????var sPassword = document.frmLogin.txtPassword.value;
?????? if( sUserName=="")
??????{
??????? alert("請輸入用戶名！");
??????? return false;
??????}
?????? if( sPassword=="")
??????{
??????? alert("請輸入密碼！");
??????? return false;
??????}
?????}
????</script>
??</body>
</html>
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登錄成功歡迎頁面:login_success.jsp
|
<
%
@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
??<title>My JSP 'login_failure.jsp' starting page</title>
??<meta http-equiv="content-type"content="text/html; charset=UTF-8">
??<meta http-equiv="pragma"content="no-cache">
??<meta http-equiv="cache-control"content="no-cache">
??<meta http-equiv="expires"content="0">
??<meta http-equiv="keywords"content="keyword1,keyword2,keyword3">
??<meta http-equiv="description"content="This is my page">
??<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
??<%
???String userName =(String)session.getAttribute ("UserName");
??%>
??<divalign=center>
???<%=userName%>
??? 歡迎您，登錄成功！
??</div>
</body>
</html>
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登錄失敗頁面:login_failure.jsp
|
<
%
@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
??<title>My JSP 'login_failure.jsp' starting page</title>
??<meta http-equiv="content-type"content="text/html; charset=UTF-8">
??<meta http-equiv="pragma"content="no-cache">
??<meta http-equiv="cache-control"content="no-cache">
??<meta http-equiv="expires"content="0">
??<meta http-equiv="keywords"content="keyword1,keyword2,keyword3">
??<meta http-equiv="description"content="This is my page">
??<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
??<%
??String userName =(String)session.getAttribute ("UserName");
??%>
??<divalign=center>
???<%=userName%>
??? 對不起，登錄失敗！
??</div>
</body>
</html>
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Servlet處理文件:LoginServlet.java
|
/**
* 該JSP程序是用來測試與MySQL數據庫的連接，
* 需要一個數據庫：LearnJSP，和其中一個表：userinfo
* 表中有兩個字段分別為：UserName varchar (20) not null,UserPwd varchar (20) not null
*/
package zieckey.login.servlet;
importjava.sql.Statement;
importjava.io.IOException;
importjava.sql.DriverManager;
importjava.sql.ResultSet;
importjava.sql.SQLException;
importjavax.servlet.Servlet;
importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
publicclass LoginServlet extends HttpServlet implements Servlet
{
public LoginServlet ()
{
??
// TODO Auto-generated constructor stub
}
/*
?? * (non-Javadoc)
?? *
?? * @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest,
?? * javax.servlet.http.HttpServletResponse)
?? */
@Override
protectedvoid doGet ( HttpServletRequest arg0, HttpServletResponse arg1 )
???throws ServletException,IOException
{
}
/*
?? * (non-Javadoc)
?? *
?? * @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest,
?? * javax.servlet.http.HttpServletResponse)
?? */
@Override
protectedvoid doPost ( HttpServletRequest request, HttpServletResponse response )
???throws ServletException,IOException
{
?? response.setContentType("text/html");
??Stringresult="";
??
// 獲取用戶名
??String sUserName =request.getParameter("txtUserName");
??if( sUserName ==""|| sUserName ==null|| sUserName.length()> 20 )
??{
???try
???{
????result="請輸入用戶名（不超過20字符）！";
????request.setAttribute("ErrorUserName",result);
???? response.sendRedirect ("login.html");
???}catch(Exception e )
???{
???}
??}
??
// 獲取密碼
??String sPasswd =request.getParameter("txtPassword");
??if( sPasswd ==""|| sPasswd ==null|| sPasswd.length()> 20 )
??{
???try
???{
????result="請輸入密碼（不超過20字符）！";
????request.setAttribute("ErrorPassword",result);
???? response.sendRedirect ("login.html");
???}catch(Exception e )
???{
???}
??}
??
// 登記JDBC驅動程序
??try
??{
???Class.forName("org.gjt.mm.mysql.Driver").newInstance();
??}catch(InstantiationException e )
??{
???
// TODO Auto-generated catch block
??? e.printStackTrace();
???System.out.println("InstantiationException");
??}catch(IllegalAccessException e )
??{
???
// TODO Auto-generated catch block
??? e.printStackTrace();
???System.out.println("IllegalAccessException");
??}catch(ClassNotFoundException e )
??{
???
// TODO Auto-generated catch block
??? e.printStackTrace();
???System.out.println("ClassNotFoundException");
??}
??
// 連接參數與Access不同
??Stringurl="jdbc:mysql://localhost/LearnJSP";
??
// 建立連接
??java.sql.Connectionconnection=null;
??Statement stmt =null;
??ResultSet rs =null;
??try
??{
???connection=DriverManager.getConnection(url,"root","011124");
??? stmt =connection.createStatement();
???
// SQL語句
???Stringsql="select * from userinfo where username='"+ sUserName
?????+"' and userpwd = '"+ sPasswd +"'";
??? rs = stmt.executeQuery(sql);
// 返回查詢結果
??}catch(SQLException e )
??{
???
// TODO Auto-generated catch block
??? e.printStackTrace();
??}
??try
??{
???if( rs.next())
// 如果記錄集非空，表明有匹配的用戶名和密碼，登陸成功
???{
????
// 登錄成功后將sUserName設置為session變量的UserName
????
// 這樣在后面就可以通過 session.getAttribute("UserName") 來獲取用戶名，
????
// 同時這樣還可以作為用戶登錄與否的判斷依據
????request.getSession().setAttribute("UserName", sUserName );
???? response.sendRedirect ("login_success.jsp");
???}else
???{
????
// 否則登錄失敗
????
//response.sendRedirect ( "MyJsp.jsp" );
???? response.sendRedirect ("login_failure.jsp");
???}
??}catch(SQLException e )
??{
???
// TODO Auto-generated catch block
??? e.printStackTrace();
??}
??try
??{
???if( null!=rs )
???{
???? rs.close();
???}
???if( null!=stmt )
???{
???? stmt.close();
???}
???if( null!=connection )
???{
????connection.close();
???}
??}catch(SQLException e )
??{
???
// TODO Auto-generated catch block
??? e.printStackTrace();
??}
}
/**
?? *
?? */
private
static
final
long serialVersionUID = 1L;
}
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為了讓這個網站正常運行還要到web.xml中注冊一下,
現該文件內容修改如下:
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<
?xml version="1.0"encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"version="2.4" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
??<servlet>
????<display-name>LoginServlet</display-name>
????<servlet-name>LoginServlet</servlet-name>
????<servlet-class>zieckey.login.servlet.LoginServlet</servlet-class>
??</servlet>
??<servlet-mapping>
????<servlet-name>LoginServlet</servlet-name>
????<url-pattern>/LoginServlet</url-pattern>
??</servlet-mapping>
</web-app>
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好了,這幾個文件就可以構成我們的這個登錄界面了.
注意事項:
1. 文件目錄形式
login.html,login_success.html,login_failure.html這三個文件放在同一目錄,
LoginServlet.java該文件的字節碼文件LoginServlet.class放在WEB-INF\classes目錄下(注意jar包順序)
現在整個工程的目錄形式是:
M:\Tomcat5.5\webapps\JSP_Servlet_JavaBean_Login 的目錄
007-01-18 15:16??? <DIR>????????? META-INF
007-01-18 15:16??? <DIR>????????? WEB-INF
007-01-18 16:17???????????? 1,801 login.html
007-01-18 15:48?????????????? 858 login_failure.jsp
007-01-18 15:40?????????????? 234 login_success.html
007-01-18 15:46?????????????? 781 MyJsp.jsp
007-01-18 16:12?????????????? 859 login_success.jsp
M:\Tomcat5.5\webapps\JSP_Servlet_JavaBean_Login\WEB-INF 的目錄
007-01-18 15:16??? <DIR>????????? classes
007-01-18 15:16??? <DIR>????????? lib
007-01-18 16:21?????????????? 606 web.xml
M:\Tomcat5.5\webapps\JSP_Servlet_JavaBean_Login\WEB-INF\classes\zieckey\login\servlet 的目錄
2007-01-18 16:18???????????? 3,900 LoginServlet.class
2. 其他注意事項
數據庫MySQL服務器程序要先啟動起來.