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JSP的login程序代码

摘要: JSP的login程序代码


JSP的login程序代码

<table cellSpacing=0 cellPadding=0 width=600 bgColor=#ffffff border=0> <tr> <td><!-- Login Manager -->
<JAVA TYPE="class">

public static boolean checkUserPermission(HttpSession mySession, HttpServletRequest request, HttpServletResponse response)
{
if (mySession.getValue("hasPermission") == null || !((Boolean) mySession.getValue ("hasPermission" )).booleanValue())
{
String requestedUrl = HttpUtils.getRequestURL(request).toString();
String queryString = request.getQueryString();
if (queryString != null)
{
requestedUrl = requestedUrl + "?" + queryString;
}
requestedUrl = response.encodeUrl(requestedUrl);
mySession.putValue("requestedUrl", requestedUrl);
return false;
}
else
{
return true;
}
}

</JAVA>

<%
// JSP文件
String goodUser = "bill";
String goodPass = "bobo";
HttpSession mySession = request.getSession(true);
String errorMessage = "Please Login To Access The Page You Requested";
boolean loginAttempt = false;
String myMethod = request.getMethod();
if (request.getParameterValues("click") != null && request.getParameterValues ("click")[0].trim().equals("Log In"))
{
loginAttempt = true;
}

if (loginAttempt)
{
String username = request.getParameterValues("user")[0].trim();
String password = request.getParameterValues("pass")[0].trim();
//out.println("username = |" + username + "| & password = |" + password + "|<BR>");
if (goodUser.equals(username) && goodPass.equals(password))
{
response.sendRedirect((String)mySession.getValue("requestedUrl"));
mySession.putValue("hasPermission", new Boolean(true));
errorMessage = "Unable to redirect: " + (String) mySession.getValue("requestedUrl");
}
else
{
errorMessage = "You did not get the Username or Password right";
}
}
else
{
errorMessage = "Haven't tried logging in yet.";
if (mySession.getValue("requestedUrl") == null)
{
mySession.putValue("requestedUrl", "/index.jsp");
}
//out.println("set userReferrer to " + mySession.getValue("redirectTo") + "<BR>");
}
%>

<CENTER>
<font color=red><%=errorMessage%></font>
<TABLE align=center>
<FORM action="adminLogin2.jsp" method=post name="login">
<TR>
<TD>Username:</TD>
<TD><input type=text name=user value=""></TD>
</TR>
<TR>
<TD>Password:</TD>
<TD><input type=password name=pass value=""></TD>
</TR>
<TR>
<TD colspan=2 align=center><input type=submit name=click value="Log In"> </TD>
</TR>
</FORM>
</TABLE>
</CENTER>
Original URL: <%= (String)mySession.getValue("requestedUrl") %>
<script language="Javascript">
// <!--
if (document.forms.login != null)
document.forms.login.user.focus();
// -->
</script> </td></tr></table>
  5.11 checkbox在jsp中的使用方法

<table cellSpacing=0 cellPadding=0 width=600 bgColor=#ffffff border=0> <tr> <td>

<%@ page language="Java" contentType="text/html" %>
<%@ page import="com.ora.jsp.util.*" %>
<html>
<body bgcolor="white">
<form action="checkbox.jsp">
<input type="checkbox" name="fruits" value="Apple">Apple<br>
<input type="checkbox" name="fruits" value="Banana">Banana<br>
<input type="checkbox" name="fruits" value="Orange">Orange<br>
<input type="submit" value="Enter">
</form>

<%
String[] picked = request.getParameterValues("fruits");
if (picked != null && picked.length != 0) {
%>
You picked the following fruits:
<form>
<input type="checkbox" name="fruits" value="Apple"
<%= ArraySupport.contains(picked, "Apple")?"checked" : "" %> >Apple<br>
<input type="checkbox" name="fruits" value="Banana"
<%= ArraySupport.contains(picked,"Banana")?"checked":"" %> >Banana<br>
<input type="checkbox" name="fruits" value="Orange"
<%= ArraySupport.contains(picked,"Orange")?"checked" : "" %> >Orange<br>
</form>
<% } %>
</body>
</html> </td></tr></table>
  5.12 request对象

  ·如何获得一个运行时刻的JSP/Servlet文件的绝对URL地址

<table cellSpacing=0 cellPadding=0 width=600 bgColor=#ffffff border=0> <tr> <td>String url = request.getRequestURL();
if (request.getQueryString() != null)
{
url += '?' + request.getQueryString();
}
URL theURL = new URL ( request.getScheme() , request.getServerName() , request.getServerPort(),url);
out.print(URL.toString());</td></tr></table>
  ·如何知道客户端通过哪个URL访问本页面

<table cellSpacing=0 cellPadding=0 width=600 bgColor=#ffffff border=0> <tr> <td>String callingPage = request.getHeader("Referer");
Out.print(callingPage);</td></tr></table>
  ·如果form中出现好几个submit按钮,JSP/Servlet如何判断哪个按钮进行了提交在form中可以这样定义:

<table cellSpacing=0 cellPadding=0 width=600 bgColor=#ffffff border=0> <tr> <td><input type=submit name="name" value="john"><br>
<input type=submit name="name" value="joe"><br>
在JSP/Servlet中使用request.getParameter("name"),根据返回值就可进行判断。</td></tr></table>
  5.13 include指令

  这个指令让你可以在JSP编译成servlet的时候可以包含进一些文件。这个指令是这样的:

<table cellSpacing=0 cellPadding=0 width=600 bgColor=#ffffff border=0> <tr> <td><%@ include file="relative url" %> </td></tr></table>
  这个指定的URL通常是指向它的JSP页面的相关解释。包含的文件内容被当作JSP文本来分析,因此可以包含静态 HTML、scripting elements、directives以及actions。

  例如,很多站点的每个页面上都包含有小的导航条。这个 include 是做这个的很好方法,省得开发者经常拷贝HTML到不同的文件中。例如:

<table cellSpacing=0 cellPadding=0 width=600 bgColor=#ffffff border=0> <tr> <td><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE>Servlet Tutorial: JavaServer Pages (JSP) 1.0</TITLE>
<META NAME="author" CONTENT="webmaster@somesite.com">
<META NAME="keywords" CONTENT="...">
<META NAME="description" CONTENT="...">
<LINK REL=STYLESHEET HREF="Site-Styles.css" TYPE="text/css">
</HEAD>
<BODY>
<%@ include file="/navbar.html" %>
<!-- Part specific to this page ... -->
</BODY>
</HTML></td></tr></table>
  既然文件是在页面被编译的时候插入的,如果导航条改变了,你需要去重新编译它所指向的所有JSP页面。注意,问题很容易在这里出现。一些读者在改变导航条后,重新运行包含导航条的JSP文件时,发现导航条不变。原因有两个:一是前面提到的include指令在JSP编译成servlet的时候包含进导航条文件;第二就是JSP文件是被编译成servlet之后再运行的,如果服务器发现JSP文件没有被修改,则直接去调用已经编译好的servlet。如此一来,当调用JSP文件时,由于直接调用了编译好的servlet,显示的结果当然就是以前的导航条了。只要稍微修改一下JSP文件,该问题就可以自行解决。

  如果导航条不是经常改变的,而且想要整个过程尽可能高效,那么在这样的环境下这是好的妥协。 如果这个 included 文件经常改变,那么建议读者使用用 jsp:include 行为(action)来代替。

</td> </tr> <tr> <td vAlign=top align=left height="100%">
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