B/S登陆例子（JSP+MYSQL）

web.xml

 

<? xml version="1.0" encoding="UTF-8" ?>
<! 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 >
   < display-name > jspLogin </ display-name >
</ web-app >

 

 index.jsp

 

  <%
  if (session.getAttribute( " passed " ) == null ) ... {
  response.sendRedirect("login.jsp");
  return;
 }
%>
passed !

 

 login.jsp

 

<% ... @ page contentType="text/html; charset=utf-8"  %>
< html >
< head >
< title >
login
</ title >
</ head >
< body  bgcolor ="#ffffff" >
<% ...
String flag=request.getParameter("flag");
if(flag!=null&&flag.equals("0")){
  out.println("Pls input valid username and password!<br><br>");
}
%>
< form  name ="form1"  method ="post"  action ="loginSuccess.jsp" >
< input  name ="username"  type ="text" >< br />
< input  name ="password"  type ="password" >< br />
< input  name ="reset"  type ="reset"  value ="reset" >
< input  name ="submit"  type ="submit"  value ="submit" >
</ form >
</ body >
</ html >

 

 

loginSuccess.jsp

 

<% @ page  import = " java.sql.* " %>
<%
String username = request.getParameter( " username " );
String password = request.getParameter( " password " );
String sql = " select * from user where username=' " + username + " ' and password=' " + password + " ' " ;
boolean  flag = false ;
//
Class.forName( " com.mysql.jdbc.Driver " ) ;
Connection conn  =  DriverManager.getConnection( " jdbc:mysql://localhost:3306/test?user=cwb&password=cwb123&useUnicode=true " );
Statement pstmt  =  conn.prepareStatement(sql) ;
ResultSet rs  =  pstmt.executeQuery(sql);

if (rs.next())  ... {
flag = true ;
}
//
rs.close() ;
pstmt.close() ;
conn.close() ;

if (flag) ... {
  session.setAttribute("passed","true");
  response.sendRedirect("index.jsp");
} else ... {
  response.sendRedirect("login.jsp?flag=0");
}
%>