System: Mac OSX
I have set up nutch so that it crawls and indexes my site. It also returns search results. My problem is that I want to customise the Nutch index.jsp and search.jsp pages to fit with my site. Ive read up and on jsp and it says its just a matter of putting in the html tags and then using <% %> to enclose the Java scriplets you want. For some reason nothing changes when i edit the files (index and search)
Here is what the original file displays:
<%# page
session="false"
import="java.io.*"
import="java.util.*"
%><%
String language =
ResourceBundle.getBundle("org.nutch.jsp.search", request.getLocale())
.getLocale().getLanguage();
String requestURI = HttpUtils.getRequestURL(request).toString();
String base = requestURI.substring(0, requestURI.lastIndexOf('/'));
response.sendRedirect(language + "/");
%>
Here is my edited version with sum gibberish test added to test it:
<html>
<head>
</head>
<body>
gigigyigig
<%# page
session="false"
import="java.io.*"
import="java.util.*"
%><%
String language =
ResourceBundle.getBundle("org.nutch.jsp.search", request.getLocale())
.getLocale().getLanguage();
String requestURI = HttpUtils.getRequestURL(request).toString();
String base = requestURI.substring(0, requestURI.lastIndexOf('/'));
response.sendRedirect(language + "/");
%>
ghjgjkbkhb
hjgjvjhvj
</body>
</html>
Nothing has changed tho and the nutch homepage/index.jsp still displays the same as original. This is my first encounter with JSP so its just what ive picked up so far. Can anyone tell me why the page isnt displaying the html with gibberish typed??
I have my search totaly modified. However I have my <html>... tags after the second scriptlet ie <% %> not <%# page.
As for your index.jsp modified it has a redirection response.sendRedirect and therefore it looks normal to me that you see nothing.
Also I presume you took care of loading the jsp pages at the right place under the tomcat/webapps tree, because the standard ant make file doesn't. So I ended up adding some Ant task to patch my test website.
Beware if you are going to change the .jar files you also need to restart Tomcat.
Related
This question already has answers here:
Difference between JspWriter and PrintWriter in Java EE?
(2 answers)
Closed 6 years ago.
I am getting split output from my JSP page, with writer.write() output first and second the JSP with tags omittted.
I have the following simple JSP page
<%# page import="com.AAA.SiteTemplate.RenderPageInterface" %>
<%# page import="java.io.Writer" %>
<%# page import="java.io.IOException" %>
<%# page import="com.NatureRelaxation.SiteTemplate.RenderPageInterfaceNull" %><%--
Created by IntelliJ IDEA.
User:
--%>
<%# page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<%
RenderPageInterface obj = (RenderPageInterface) request.getAttribute("renderPageInterface");
if (obj == null){
obj = new RenderPageInterfaceNull();
}
%>
<title><% response.getWriter().write(obj.getTitle()); %></title>
<style type="text/css">
</style>
</head>
<body>
<%
obj.renderHTML(response.getWriter());
%>
</body>
</html>
and I include it via this small function:
public static void doRequest(HttpServletRequest req, HttpServletResponse res, RenderPageInterface renderPageInterface) throws ServletException, IOException{
req.setAttribute("renderPageInterface", renderPageInterface);
RequestDispatcher rd = req.getRequestDispatcher("/WEB-INF/templates/header.jsp");
rd.include(req, res);
}
The response that I am getting now is
My page titleMypagebody....
<html>
<head>
<title></title>
etc. There are 4 newlines in the middle. I'm thinking it must be a compiler error, but clearing caches (IntelliJ) and restarting, redeploying to Tomcat 8 doesn't fix it. All worked as normal until server was restarted, but nothing fixes it now. I even run the debugger on the JSP and all goes in order.
Update:
It runs fine without this tag "<% response.getWriter().write(obj.getTitle()); %>", but when the tag is there, both the body and the title get written at the top and the template at the bottom. getTitle() returns a String.
I figured it out fast enough, but it was quite tricky. "response.getWriter()" and JSP's "out" variable (which I did not know about), are not the same thing.
It is by coincidence that my code previously worked.
I also had to include jsp.api.jar before I could use the "out" (JSPWriter) variable.
Relevant info here:
Difference between JspWriter and PrintWriter in Java EE?
what is difference between JspWriter and PrintWriter?
An example will make this clearer!
The jsp file...
<%# taglib prefix ="jam" uri= "http://jam.tld" %>
<%# page language="java" contentType="text/html; charset=UTF-8" pageEncoding="ISO-8859-1"%>
<%
String targetPage = true ? "toast" : "bread";
%>
<jam:text onmousedown="movePage('<%=targetPage%>');" id="<%=targetPage%>"><%=targetPage%></jam:text>
Note - the taglib is not mine and I have no control over it. (it isn't really called jam either :).
This then creates this HTML...
<td onmousedown="movePage('<%=targetpage%>;');" id="toast">toast</td>
Which as you can see: the <%=targetPage%> was only replaced/parsed in the non-javascript bit?
The compiled jsp file looks like this:
jspx_th_jam_005ftext_005f2.setOnmousedown("movepage('<%=targetpage%>')");
Anyone know what is going on, or how to fix it?
Why is the <%=%> tag being ignored when it is part of JavaScript statement?
:)
Here's a bit of a cheat solution, you dont need the JSP tag in that JS call. In fact, it's tidier this way
<jam:text onmousedown="movePage(this.id);" id="<%=targetPage%>"><%=targetPage%></jam:text>
I've read most of the online resources for building a simple "Hello World" app using Java and Struts 2. I understand the simple stuff. My problem is that I'm trying to expand that learning and build a large scale app, and I just don't see how to connect the dots.
Scenario:
I've got three views to begin with: Home.jsp, MyAccount.jsp, Contact.jsp. Each has the following HTML:
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<%#taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script type="text/javascript" src="js/common.js"></script>
...
</head>
<body>
<!-- If logged in, says "hello <s:property name="username">"
Else displays link to .show() #loginPane -->
<div id="accountHeader">...</div>
<!-- Displays <s:textfield> tags and <s:submit> tag to accept username and password -->
<div id="loginPane" style="display: none">...</div>
<header>...</header>
<nav>...</nav>
<!-- Displays view-specific content that includes Struts 2 tags -->
<div id="content">...</div>
<footer>...</footer>
</body>
</html>
So, obviously there is a lot of code common to each view (anything not in #content div).
How do I architect these views for code reuse?
What I've tried:
Placing common code in common.js and using jQuery .html() calls to populate <div>s. [Doesn't work because jQuery cannot generate code with <s:> tags.]
Using only one .jsp view file and placing view-specific code in common.js to be generated with jQuery .html() calls. [Doesn't work for the same reason -- jQuery cannot generate code with <s:> tags.]
Placing all view components in .jspf files and loading each with jQuery .load() calls from common.js. [Doesn't work -- I'm guessing the .jspf files need the Struts 2 <%taglib ...%> included in each, but jQuery .load() treats the <%taglib ...%> as text to be displayed in the <div>... and also fails to properly generate the <s:> tags.]
What is the proper way to do this? How do I architect my view(s) for code reuse?
My apologies if this isn't the proper forum to ask for architecture help, but I'm really struggling here... Perhaps point me to a more appropriate forum or an online tutorial that addresses this type of architecture?
Thanks in advance!
I've used several methods to accomplish this type of re-use of code including Tiles and tooling around with Sitemesh and other template frameworks. What I've found is that, much as Steven Benitez, in the end I preferred to use JSP taglibs, native Struts2 taglibs, and JSTL to essentially build out my own templating routines. The main reason I prefer this is that there tends to be less overhead and it's been a lot easier to maintain and extend in the long run.
Generally What I do is define my base template, index.jsp for example, and then in each independent Struts controller class I will define what page fragment is used. I try to split my controllers up in such a way that each page or function is handled by a single controller and I implement the Preparable interface. This way I can set a parameter for the page to reference. Sometimes I set it as a variable in the controller class, sometimes a sessions variable depending on what type of stating I need for the application.
Once I have a variable with the page to reference, I can just use a JSTL import or Struts include tag to load the page fragment.
The controller class would look something like this:
#Results({
#Result(name = "success", location = "/WEB-INF/content/index.jsp")
})
public class IndexController extends RestActionSupport implements Preparable{
private String page;
private String pageTitle;
#Override
public void prepare() throws Exception {
page = "home";
pageTitle= "My Home Page";
}
...
}
And then the JSP would look something like this:
<%# taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%# taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<%# taglib prefix="s" uri="/struts-tags"%>
<html>
<head>
<title> ${pageTitle}</title>
</head>
<body>
<c:import url="${page}.jsp" />
</body>
</html>
EDIT: Fragment page example:
<%# taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%# taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<%# taglib prefix="s" uri="/struts-tags"%>
<div>
<h1>Welcome Home!</h1>
</div>
<script type='text/javascript'>
$(document).ready(function() {
// page specific scripting if needed
);
</script>
You can encapsulate common template code in JSP tag files, as explained in this answer or you can also use decorator frameworks such as Tiles or SiteMesh to do this.
Personally, I prefer JSP tag files. Do not attempt to write out HTML with jQuery or to put all of your code into a single JSP.
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.
Good day!
I encountered the following error upon running my JSP program.
java.lang.IllegalStateException: PWC3991: getOutputStream() has already been called for this response
It seems like the html file inside my JSP doesn't work.
My code is as follows:
<%#page import = "java.util.*"%>
<%#page import = "javax.servlet.*"%>
<%#page import = "javax.servlet.http.*"%>
<%#page import= "session.*" %>
<%#page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<%
Item item = (Item) request.getAttribute("invenItem");
if (item != null) {
out.println("<html><title>Inventory Item</title>");
out.println("<body><h1>Inventory Item Details:</h1>");
out.println("Stock ID : " + item.getStockID() + "<br/>");
out.println("Name : " + item.getItemName() + "<br/>");
out.println("Unit Price: " + item.getUnitPrice() + "<br/>");
out.println("On Stock : " + item.getOnStock() + "<br/>");
out.println("</body>");
out.println("</html>");
} else {
RequestDispatcher rd = request.getRequestDispatcher("DataForm.html"); //NOT WORKING
rd.include(request, response);
out.println("<br>Item not found...<br>");
rd = request.getRequestDispatcher("ItemEntry.html"); //NOT WORKING
rd.include(request, response);
}
%>
</body>
</html>
My html Files are located inside the folder WEB-INF. How can I make it work? DO i need to import it also? Thank you.
Don't use scriptlets (those <% %> things). JSP is a template technology for HTML. You don't need all those nasty out.println() things for HTML. Just write HTML plain in JSP.
So, instead of
<%
out.println("<html><title>Inventory Item</title>");
%>
just do
<html><title>Inventory Item</title>
(note that this results in invalid HTML, there should be only one <html> tag in a HTML page and only one <title> in the <head>, but that's a different problem, the w3 HTML validator should give a lot of hints and answers, also get yourself through some HTML tutorials)
JSP offers EL (Expression Language, those ${ } things) to access backend data, i.e. the data which is present as attribute in page, request, session and application scopes. It can be accessed using the attribute name.
So, instead of
<%
Item item = (Item) request.getAttribute("invenItem");
%>
use
${invenItem}
and instead of
<%
out.println("Stock ID : " + item.getStockID() + "<br/>");
%>
use
Stock ID: ${invenItem.stockID}<br/>
JSP also offers taglibs like JSTL to control the page flow and output.
So, instead of
<%
if (item != null) {
} else {
}
%>
use
<c:choose>
<c:when test="${invenItem != null}">
</c:when>
<c:otherwise>
</c:otherwise>
</c:choose>
JSP also offers <jsp:include> tag to include page fragments.
So, instead of
<%
RequestDispatcher rd = request.getRequestDispatcher("DataForm.html"); //NOT WORKING
rd.include(request, response);
%>
use
<jsp:include page="/WEB-INF/DataForm.jsp" />
(and rename it to .jsp)
And the exception will disappear.
See also:
JSP tag info page
How to avoid Java code in JSP files?
Java web development, what skills do I need?
Unrelated to the concrete problem, almost all of the links in this answer was already (in)directly given to you in your previous questions. Take them serious. To become a great programmer (as you ever stated in a question/comment), take some time to get yourself through those links (and the links in the links).
Firstly, try to avoid putting code onto your JSP page - it violates the MVC/separation of concerns paradigm that is a central part of JSP.
Second, plain old JSP's getting a bit old - using JSF/facelets/etc is recommended these days.
As for your actual problem, I'm not totally familiar with the technique you're employing, but the exception basically means that you've tried to send content after the latest point at which your able to (generally, after sending headers). In this case, I think what's happening is that you've already started sending the current page when you ask it to send a different page.
Simplest fix I can think of: rather than trying a conditional include based on results, just redirect to a different page.
The error indicates that the error lines of code cannot be called once something has been printed out to the output stream in jsp (including even the doctype declaration)
So you can try to put those pieces of code at the top of your page.
You can not use
out.print() and Requestdispatcher simultaneously....
It means after execution of out.print() there should not be any execution of statement with requestdispatcher.forward()....
So remove out.println() form else block.