网上有好多，去下载好了

<!-- 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>

<%
// THIS IS A JSP FILE

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>

什么东西都不是通用的，要自己看看写写