In my JSP page,I use <%=TITLE %> to show the page title, sometimes it is ok.But sometimes the page show that can not cpmplie the code <%=TITLE %>.
So I change the code to ${TITLE}，and it is OK.What is different between <%=TITLE %> and ${TITLE} in jsp?
Here is my page code:
<%# page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%# taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<!DOCTYPE html>
<html lang="en">
<head>
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<base href="<%=basePath%>">
<title><%=TITLE %></title>
<meta name="description" content="${DESCRIPTION}">
<meta name="keyword" content="${KEYWORD}">
</head>
I define them in the controller:
ModelAndView mv = this.getModelAndView();
mv.addObject("DESCRIPTION","MYDESCRIPTION"));
mv.addObject("KEYWORD","MYKEYWORD");
mv.addObject("TITLE","MYTITLE");
return mv;
Answer according to context of your Question
What is different between “<%=TITLE %> ” and “${TITLE} ” in jsp?
Since most of the times we print dynamic data in JSP page using out.print() method, there is a shortcut to do this through JSP Expressions. JSP Expression starts with <%= and ends with %>.
<% out.print(TITLE); %>
above statement is called scriptlet can be written using JSP Expression as
<%= TITLE %>
We can use scriptlets and JSP expressions to retrieve attributes and parameters in JSP with java code and use it for view purpose. But for web designers, java code is hard to understand and that’s why JSP Specs 2.0 introduced Expression Language (EL) through which we can get attributes and parameters easily using HTML like tags.
Expression language syntax is
${TITLE}
and we can use EL implicit objects and EL operators to retrieve the attributes from different scopes and use them in JSP page.
UPDATE
According to your controller related query
I say to write like this
<title><%=request.getAttribute("TITLE"); %></title>
because it's stored as a request attribute.
NOTE
Scriptlets are discouraged since JSP 2.0 which was released almost a decade(!) ago. So Please use Expression Language (EL).
Related
I am developing a simple Struts 1.x web application and there's a file named success.jsp and this is the sample code:
<%# taglib uri="http://struts.apache.org/tags-bean" prefix="bean"%>
<%# taglib uri="http://struts.apache.org/tags-html" prefix="html"%>
<%# taglib uri="http://struts.apache.org/tags-logic" prefix="logic"%>
<%# taglib uri="http://struts.apache.org/tags-nested" prefix="nested"%>
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html:html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>success.jsp</title>
<html:base/>
</head>
<body>
Go to myStart
</body>
</html:html>
By default, <html>was used instead of <html:html>, may I know what is the major difference between these two elements? Is it necessary to specify the uses of them? Besides, what is the major function for <html:base/> element?
Btw I found some definitions for these elements but I need clarification:
<html:html> Renders an HTML <html> element with language attributes extracted from the user's current Locale object, if there is one.
<html:base> Renders an HTML element with an href attribute pointing to the absolute location of the enclosing JSP page. This tag is valid only when nested inside an HTML <head> element. This tag is useful because it allows you to use relative URL references in the page that are calculated based on the URL of the page itself, rather than the URL to which the most recent submit took place (which is where the browser would normally resolve relative references against).
The <html:html> tag is a Struts 1.x JSP Taglib directive, declared in this line on your JSP Page:
<%# taglib uri="http://struts.apache.org/tags-html" prefix="html"%>
These custom tag(s) are typically of the form <prefix:tagname>. The prefix declared on taglib is what binds your taglib container to the list of markups available in the taglib.
In essence <html:html> tells the taglib, prefixed html to render a html element when JSP is rendered.
So to answer your question <html> is a HTML directive while <html:html> is a Struts JSP taglib tag to generate a HTML <html> directive.
This question already has an answer here:
How do I pass current item to Java method by clicking a hyperlink or button in JSP page?
(1 answer)
Closed 7 years ago.
I have a facultylist.jsp page which displays List<Faculty> as a request attribute parameter in forEach loop and I want every item in this loop to be a link to specified faculty facultyview.jsp. How can I achieve that ?
facultylist.jsp:
<%# page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%#taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Faculties</title>
</head>
<body>
<h1>Faculties list</h1>
<ul>
<c:forEach var="faculty" items="${faculties}">
<li>${faculty.name}</li>
</c:forEach>
</ul>
</body>
</html>
facultyview.jsp:
<%# page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%#taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Faculty</title>
</head>
<body>
<h1>${faculty.name}</h1>
<ul>
<li>Faculty name: <c:out value="${requestScope.name}"></c:out></li>
<li>Total seats: <c:out value="${requestScope.total_seats}"></c:out></li>
<li>Budget seats: <c:out value="${requestScope.budget_seats}"></c:out></li>
</ul>
apply for this faculty
</body>
</html>
I don't know if its may help, but I'm using following technologies: tomcat, jsp, servlets and log4j.In my project I have one FrontController, which is a servlet that interacts with Command pattern - each Command returns a path to resource and action type: forward or redirect.
You can solve your issue by adding a query params to the link, edit with respect to the comment. Note that you cannot access directly the JSP pages that reside under WEB-INF folder. Also, to encode properly the paramters, better construct url like
<c:url value="facultyview.jsp" var="url">
<c:param name="name" value="${faculty.name}"/>
<c:param name="total_seats" value="${faculty.total_seats}"/>
<c:param name="budget_seats" value="${faculty.budget_seats}"/>
</c:url>
<li>${faculty.name}</li>
and than than in your facultyview.jsp read from the query params
<li>Faculty name: ${param.name}</li>
<li>Total seats: ${param.total_seats}</li>
<li>Budget seats:${param.budget_seats}</li>
This direct JSP communication should solve your immediate issue, but a truly proper way would be to pass an id of a faculty to servlet, fetch the faculty instance, place in the model and pass to the view.
in other way is just take the selected value from the drop down with a name and forward it to front controller servlet ,there use if else conditions and depends on the value you could forward the request to corresponding jsp or servlet
<select name="value"> in jsp
String value=req.getParameter("value"); in servlet
if()
else if()
If you have a field in Faculty entity simply:
${faculty.name}
#Mark: faculty represents an entity from database, i'm not sure if I want to change it adding another field, or you mean some other way ?
Add a field does not means you must change database, you can have a Helper entity that inherits from Faculty and have more fields you can need,
public class FacultyFormHelper extends Faculty implements Serializable {
private String URL;
and in your view:
${facultyHelper.name}
But, If you don't want to modify your database, either create a helper class, you may add onclick event to the <a>
<a onclick="goToURL(${faculty.id})">
Then retrieve the data... i'm not sure how you get the urls... from a variable in the view, ajax call or wherever you have this URL...
I have two jsp pages. I am trying to add "Russian" language. Russian characters are shown perfectly on jsp page, but when I try to send this value to another jsp page from parameter then in second jsp page this value is changed to different characters. This problem is only in Russian Language and not in others such as Italy and French.
For example
On demo.jsp page the russian character "приветствие" is shown correctly.
but when I try to send it to another page "test.jsp" then some unknown
characters are shown like "!C<Cä5 Cô>CôCC´OD=Cä5!"
Code:
demo.jsp
String welcometext=langP.get("welcome");
<jsp:include page="<%=test.jsp%>">
<jsp:param name="wlc" value="<%=Encode.hex8Code(welcometext)%>" />
</jsp:include>
In test.jsp
String title = Encode.utfToUnicode(Decode.hex8Decode(request.getParameter("wlc")));
System.out.println(" Russial welcome test "+welcome);
Is there any special code we need to add for Russia while sending them in query parameters??
Please note* the following code are already written else it would have given problem for French and Italy language too..
<%# page contentType="text/html; charset=UTF-8" %>
<META http-equiv="Content-Type" content="text/html; charset=UTF-8">
Also tried with following but didn't help out!
request.setCharacterEncoding("UTF-8")
Try to add <% request.setCharacterEncoding("UTF-8"); %> to your main jsp page:
Here is my example:
demo.jsp
<%#page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<% request.setCharacterEncoding("UTF-8"); %>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<h1>Привет</h1>
<jsp:include page="/test.jsp" flush="true">
<jsp:param name="wlc" value="Привет"/>
</jsp:include>
</body>
</html>
test.jsp
<h1>Param values is</h1>
<%
String hello = request.getParameter("wlc");
out.print(hello);
%>
I don't know the better solution but the following code solved this issue. I kept the variable in session attribute.
demo.jsp
session.setAttribute("welcometext", welcometext);
test.jsp
String welcometest=(String) session.getAttribute("welcometext");
Below is the code I have in index.jsp using jstl 1.2.
<%# taglib prefix = "c" uri="http://java.sun.com/jstl/core"%>
<% String[] setName = {"Hello", "you", "are", "using", "jstl", "in", "jsp"};
request.setAttribute("getName", setName);
%>
<html>
<body>
<table>
<tr><td>Print</td></tr>
<c:forEach var="itemName" items="#{getName}" >
<tr>
<td>${itemName}</td>
</tr>
</c:forEach>
</table>
</body>
</html>
The output I was expecting is as below
Print
Hello
you
are
using
jstl
in
jsp
However below is what I am getting
Print
#{name}
Please let me know where I am missing
Below is the only jar file I have in WEB-INF/lib folder
jstl-1.2.jar
Thanks in advance
Fahim
Note: Adding Java and JSP tag as person who have knowledge of Java and JSP might be knowing JSTL too...
Here,
<%# taglib prefix = "c" uri="http://java.sun.com/jstl/core"%>
You're specifying the wrong JSTL taglib URL. This one is for JSTL 1.0. After JSTL 1.1 it requires a /jsp in the path. See also the JSTL 1.1 tag library documentation.
<%# taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
As to the of the code (and to reply on all those duplicate answers complaining to use ${} instead), the #{} syntax will only work inside JSP when you're targeting a Servlet 2.5 / 2.1 compatible container with a web.xml conforming Servlet 2.5 spec. Tomcat 6.0 is an example of such a container. The #{} will indeed not work in JSP tags on older containers such as Tomcat 5.5 or older.
For clarity and to avoid confusion among starters, better use ${} all the time in JSP tags. Also better use self-documenting variable names.
<%# taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%
String[] names = {"Hello", "you", "are", "using", "jstl", "in", "jsp"};
request.setAttribute("names", names);
%>
<!DOCTYPE html>
<html lang="en">
<head>
<title>JSTL demo</title>
</head>
<body>
<table>
<tr><td>Print</td></tr>
<c:forEach items="${names}" var="name">
<tr><td>${name}</td></tr>
</c:forEach>
</table>
</body>
</html>
See also:
Our JSTL wiki page
Difference between JSP EL, JSF EL and Unified EL
In JSTL 1.2, you don't want to use #{name} in pure JSP, that's only a JSF artifact. Instead, simply use ${name}.
You need to refer items using expression language like ${name}
U r using # instead of $ before name
Let me know if this resolves.
#{name} is not a valid Java variable reference - looks like you are confusing it with JQuery selector.
Anyways try just using items="${name}"
#{name} is should be like ${name}
oh! might be the jars related to JSTL. check thins link for those jars to include in your project
Below is the final code I am using and it is running...
Posting so that someone can use it... Might help me tomorrow ;)
<%# page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<%# taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<% String[] setName = {"Hello", "you", "are", "using", "jstl", "in", "jsp"};
request.setAttribute("getName", setName);
%>
<html>
<body>
<table>
<tr><td>Print</td></tr>
<c:forEach var="itemName" items="#{getName}">
<tr>
<td>${itemName}</td>
</tr>
</c:forEach>
</table>
</body>
</html>
Learning : I was using <%# taglib prefix="c" uri="http://java.sun.com/jstl/core" %> instead of <%# taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
i have the following JSP:
<%# page contentType="text/html" pageEncoding="UTF-8"%>
<%# taglib uri="http://java.sun.com/jstl/core" prefix="c" %>
<%# page isELIgnored="false"%>
<!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><c:out value="${it.title}"/></title>
</head>
<body>
<c:forEach var="speaker" items="${it.speakers}" varStatus="stat">
<ul>
<li><c:out value="${speaker.person.firstName}" /> <c:out value="${speaker.person.lastName}" />, <c:out value="${speaker.person.address.city.zip}" /> <c:out value="${speaker.person.address.city.name}" /></li>
</ul>
</c:forEach>
</body>
</html>
Eclipse warns me about every instance of EL Expressions in my code:
Warning [line 10]: "value" does not support runtime expressions
Warning [line 13]: "items" does not support runtime expressions
...
this is however not true, EL gets evaluated correctly by the server.
Can anyone hint me in the right direction why eclipse is warning me about those EL expressions?
Your taglib directive imports a JSTL 1.0 taglib. It should be JSTL 1.1 instead (note the difference in URI):
<%# taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
Possible solution (found here):
Twin Libraries
The JSTL tag libraries come in two
versions which differ only in the way
they support the use of runtime
expressions for attribute values.
In the JSTL-RT tag library,
expressions are specified in the
page's scripting language. This is
exactly how things currently work in
current tag libraries.
In the JSTL-EL tag library,
expressions are specified in the JSTL
expression language. An expression is
a String literal in the syntax of the
EL.
When using the EL tag library you
cannot pass a scripting language
expression for the value of an
attribute. This rule makes it possible
to validate the syntax of an
expression at translation time.
So maybe your eclipse and the server use different tag libraries.
try this:
change this:
<%#taglib prefix="c" uri="http://java.sun.com/jstl/core"%>
to yes:
<%#taglib prefix="c" uri="http://java.sun.com/jstl/core_rt"%>
hope it works for you. I got this from www.csdn.net.