Home > Developer > JSP

JSP login program code

Source: Internet
Author: User
Developer on Alibaba Coud: Build your first app with APIs, SDKs, and tutorials on the Alibaba Cloud. Read more ＞

JSP login program code

<! -- 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 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'ttried 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>

5.11 how to use checkbox in jsp

<% @ 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>

5.12 request object

· How to obtain the absolute URL of a JSP/Servlet File at runtime

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 ());

· How to know which URL the client accesses this page

String callingPage = request. getHeader ("Referer ");
Out. print (callingPage );

· If several submit buttons appear in the form, JSP/Servlet can define how to determine which button is submitted in form as follows:

<Input type = submit name = "name" value = "john"> <br>
<Input type = submit name = "name" value = "joe"> <br>
Use request. getParameter ("name") in JSP/Servlet to determine based on the returned value.

5.13 include command

This command allows you to include some files when JSP is compiled into a servlet. This command is as follows:

<% @ Include file = "relative url" %>

The specified URL usually points to its JSP page. The content of the contained file is analyzed as JSP text, so it can contain static HTML, scripting elements, directives, and actions.

For example, each page of many sites contains a small navigation bar. This include is a good way to do this, saving developers from copying HTML to different files. For example:

<! Doctype html public "-// W3C // dtd html 4.0 Transitional // EN">
<HTML>
<HEAD>
<TITLE> Servlet Tutorial: assumerver 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>

Since the file is inserted when the page is compiled, if the navigation bar changes, you need to re-compile all the JSP pages it points. Note that the problem may easily occur here. When some readers re-run the JSP file containing the navigation bar after changing the navigation bar, they find that the navigation bar remains unchanged. There are two reasons: first, the include command mentioned above is included in the navigation bar file when JSP is compiled into servlet; second, the JSP file is compiled into servlet and then run, if the server finds that the JSP file is not modified, call the compiled servlet directly. In this way, when calling the JSP file, because the compiled servlet is directly called, The displayed result is of course the previous navigation bar. You only need to modify the JSP file a little, and the problem can be solved by yourself.

If the navigation bar does not change frequently and you want to make the whole process as efficient as possible, this is a good compromise in such an environment. If the extended ded file changes frequently, we recommend that you use jsp: include action instead.

This article is an English version of an article which is originally in the Chinese language on aliyun.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact@alibabacloud.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

Related Keywords:
first jsp program in eclipse jsp projects with source code convert php to jsp code online login program in php html simple program code program exit code morse code program
Related Article
Set the html/jsp edit automatic prompt in MyEclipse 9/10 __html
JSP (6)--JSP declaration
Springboot load JSP refresh JSP, refresh controller (try it Y...
Javax.servlet.jsp.PageContext cannot is resolved to a type
A simple calculator for JSP exercises (using Jsp+javabean mode)
Use absolute path $ {pagecontext. Request. contextpath} in JSP}

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

What's Trending
Top 10 Tags
datastax versions naming convention zookeeper client class definition md5 microsoft sql server 2005 data structures exception handling error handling
Top 10 Keywords
microsoft download center down wordpress address url site address url wordpress address url windows installer 4 0 download 302 not found web address url definition site address url wordpress db2 integer mac os installation step by step pdf abbreviation for return

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

Get Started for Free

  • Sales Support

    1 on 1 presale consultation

    Chat Contact Sales

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

    Open a Ticket

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.

    Learn More