I currently have a JSP page with a Form for the user to enter their name, but what I want is to get the user forwarded to a different JSP page after form submission and to carry on their name to be used.
I don't want to use JSTL EL just simple JSP uses.
I was thinking of using a bean storing the detail in a session but how would it work.
Thanks.
You'd have JSP enter the info into a form and POST it to a servlet. The servlet would validate the form input, instantiate the bean, add it to session, and redirect the response to the second JSP to display.
You need a servlet in-between. JSPs using JSTL are for display; using the servlet this way is called MVC 2. Another way to think of it is the front controller pattern, where a single servlet handles all mapped requests and simply routes them to controllers/handlers.
duffymo you have the best idea but here is a quick solution by just passing things through the JSP.
Here is the JSP with the form
<%# page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head><title>Simple jsp page</title></head>
<body><form name="test" action="./stackTest2.jsp" method="POST">
Text Field<input type="text" name="textField">
<input type="submit">
</form> </body>
</html>
and then the second page looks like this:
<html>
<head><title>Simple jsp page</title></head>
<body><%=request.getParameter("textField")%></body>
</html>
And then put information in a hidden field, you can get information by using the request.getParameter method. This just prints out what was in the form, but using the same idea for inputting it in to the hidden field in a form. I recommend this as all my experience with sessions have ended in a failure. I STRONGLY DO NOT Recommend this method, MVC is a much better way of developing things.
Dean
Related
I'm fairly new to Thymleaf and Spring, and I'm taking a course that is using JSP for client view pages. I couldn't set up JSP using Spring Initializr so I resorted to using Thymeleaf instead (I figured I would end up using Thymeleaf normally anyways)
My question is, how Do i pass form data from one HTML, to another page? I've tried looking at the documentation, and googling around and couldn't find anything.
I have already tried using, a class to set up the Objects, and variables (and i know this is a way of doing it, i'll eventually get to the part of learning how to do that), but I'm just trying to get data from one form to another page.
In JSP you can do this
htmlpageOne.html
<form action="processForm" method="GET">
<input type="text" name="studentID"/>
<input type="submit"/>
</form>
htmlpageTwo.html
<body>
Student ID: ${param.studentID}
</body>
Using JSP you can call the studentID from the past form without having to store it in any Object and having to create any thing else.
I know the data won't really go anywhere and isn't stored, but just for simplicity and demonstration, is there any way to do the same with Thymeleaf?
any help or direction would be very much appreciated
Yes, thymeleaf supports request parameters.
https://www.thymeleaf.org/doc/articles/springmvcaccessdata.html#request-parameters
<body>
Student ID: <span th:text="${param.studentID}" />
</body>
I am writing a JSP code which goes like this:
<% if(---)
{----}
else
{ ---
%>
<jsp:forward page="error.jsp">
<jsp:param name="" value=""/>
</jsp:forward>
<%
}
%>
The error.jsp is in the same directory as the current jsp file still it is throwing "class not found exception". What to do?
Not much clear from your question what you are trying to achieve but If you are adding the another jsp page within current jsp page then use jsp:include otherwise if trying to redirect to another jsp page then following could be used.
Use in scriptlet response.sendRedirect in your case as below:
<%
response.setHeader("header_key", "header_value");
response.sendRedirect("your_page_location")
%>
Above could be used for external pages as well like "www.google.com"
On the other hand you could use request forward with all old parameters and data from calling page. See below:
RequestDispatcher rd = servletContext.getRequestDispatcher("/pathToResource");
rd.forward(request, response);
Also, another easy way could be to submit a form with action="your_jsp.jsp" but this should be used in case of form submissions where you are sending some data etc.
Make choice for any of above options on a case basis.
Hope it helps!
I have jsp page that imports Testing.java
<jsp:useBean id="test" scope="session" class="Testing" />
<jsp:useBean id="sb" scope="session" class="SessionBean" />
<jsp:useBean id="eb" scope="session" class="ErrorBean" />
I need to call public method that is in Testing class after user confirms changes.
this is what I have so far:
<tr>
<td align="left">
<a href="<%=test.persistPrintingInfo(eb,sb) %>" >
<img src="../images/update.gif" OnClick="if( !confirm('Update printing information?')) return false"></a>
</td>
</tr>
Does anyone know how to do this?
Can I maybe call javascript method and call persistPrintingInfo() through javascript?
the page has been sent by the server to your browser. while javascript can modify the content of your page , in order to call a bean's method you must make a call to the server(a request to the servlet) beacause the bean lives on the server side. and this call can be made by creating an url mapped to the servlet, or a form whose action is the servlet
`<FORM ACTION="${pageContext.request.contextPath}/sampleServlet">`
if the form's method is GET, then on the doGet() method of the servlet you call your bean's method.
this form does not need to contain any kind of field. it is created just to make a request to the servlet. while you would normally click the submit button to proceed to the action, this time we will submit the form through javascript. with some javascript tricks, i think this form can also be hidden, because you don't actually need it to be displayed in your page
so you simply create this form in your jsp, and submit it through javascript , like this:
on your link, you will have onClick=myJavascriptMethod(); in your jsp, you create a javascript block
<script type="text/javascript">
function myJavascriptMethod)=()
{
document.forms["myform"].submit();
}
</script>
You can use this way, although there is better approaches using servlets.
<%com.example.Testing.yourMethod()%>
a second approach which i found while googling is this one:
How do I pass current item to Java method by clicking a hyperlink or button in JSP page?
in your case, the code will be
<img.. >
the newPage.jsp will contain just
<%yourPackage.YourClass.yourMethod()%>
I have a parent jsp a.jsp which includes another jsp b.jsp. I am calculating some values in b.jsp which needs to be used in parent jsp a.jsp , which will pass this calculated value to another jsp say c.jsp. How can I evaluate value in child jsp and pass it to parent jsp before that page completely loads?
How are you including the "child" jar inside the parent? static or dynamic import?
if you have
<%# include file="myFile.jsp" %>
change it by
<jsp:include file="myFile.jsp" />
then in the parent set a property in the request (not in the session, that would be "dirtier"):
<% request.setAttribute("attrName", myValue) %>
finally, in the "child" jsp:
<% myValue = (MyValueType)request.getAttribute("attrName") %>
If you need to pass an attribute between including and included jsp (and viceversa)you should use the page context, which is the more short context (from lifecycle perspective)
You can set variables in the request in b.jsp, and use them in parent.jsp. But you can only use them in the parent jsp after the <jsp:include> tag. Remember that this is all evaluated on the server side, so when you say "before that page completely loads," you can be guaranteed that the server has evaluated it before the browser has loaded it. If you mean that you want to delay evaluation on the server until some code below it is evaluated, that's not going to be possible. At least not like this.
b.jsp
<%# taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<c:set var="myVar" scope="request" value="Hello"/>
parent.jsp
<%# taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<jsp:include page="b.jsp"></jsp:include>
<span>
The value is ${requestScope.myVar}.
</span>
You could you session scope to accomplish this.
(b.jsp)
session.setAttribute("value",value);
(c.jsp)
session.getAttribute("value");
However, I would recommend doing some major restructuring instead. In your example, the value of your data depends on the order of the elements on the page. If you ever need to re-arrange things (for instance, moving the b.jsp include after the c.jsp include), you risk breaking the business logic.
A good pattern for web development is a model-view-controller pattern. The "controller" determines what page should be displayed, the "model" calculates all the data and makes it available, and the "view" does the display and formatting.
I would recommend reviewing this article, which is helpful for understanding why MVC is a valuable approach:
http://www.javaranch.com/journal/200603/Journal200603.jsp#a5
Edit: As other users have mentioned, request scope would be cleaner than session scope. However, I still recommend determining the value first before writing any display content.
I have JPSs that represent Components. I want to have these component JSPs write some HTML before and after the contents of the JSP is executed.
component.jsp
<#page session="false">
<%= "hello " + "world" %>
when this JSP/servlet is rendered, I want it to render:
<div class="component">
hello world
</div>
I want to be able to create various "wrappers", and depending on the JSP, include wrap the contents of the JSP with the correct content. If I want to change/augment the wrapper down the road, I want to only do it in one place (Could be 100s of components).
Can i do something with <#page extends="..."> possibly?
Thanks
What do you want is named: tag files. Introduced on JSP 2.0
With this approach you can write JSP tags using jsp, therefore you need to create a folder named WEB-INF/tags, and create a 'normal' jsp within this folder.
The tag that you want to create needs to have the following start instruction:
<%#tag description="tag description" %> in order to indicate this is a tag.
To use it you will need to reference the tags you want to use with the following instruction: <%# taglib tagdir="/WEB-INF/tags" prefix="custom"%>
So, you can do something like:
WEB-INF/tags/myTag.tag
<%#tag description="hello tag" %>
<%#attribute name="name" required="false" type="java.lang.String"%>
<html><head></head><body>
<h1>Hello <%=name%></h1>
<jsp:doBody />
</body>
index.jsp
<%# taglib tagdir="/WEB-INF/tags" prefix="custom"%>
<custom:myTag name="My Name">this is the content</custom:myTag>
The result will be a page printing
<html><head></head><body>
<h1>Hello My Name</h1>
this is the content
</body>
This is a terrible idea. JSPs with scriptlets are 1998 technology. No one writes these anymore.
If you must write JSPs, you're better off using JSTL and something like SiteMesh or Tiles to composite pages.
An even better idea would be to start moving towards something that might allow you to easily run a mobile solution alongside your web app. Services and templates would be my preference over JSPs.