In PHP we can do the following with the help of Variable variables in PHP:
$privateVar = 'Hello!';
$publicVar = 'privateVar';
echo $$publicVar; // Hello!
Suppose we have the following chunk of Java code:
request.setAttribute("privateVar", "Hello!");
request.setAttribute("publicVar", "privateVar");
I've tried the following but an error occurs.
${${publicVar}}
Does anyone know how we can get value of privateVar via using only publicVar in JSP (JSTL)?
UPDATE 1:
I have a custom tag which allows to print a message if an object foo doesn't have a field bar.
I know I must catch exceptions in the case but I don't want to handle ones in JSP. I want to do it only in CustomTag file.
<%-- JSP file --%>
<ctf:tagName varName="foo.bar" />
<%-- CustomTag file --%>
<%# attribute name="varName" required="true" rtexprvalue="true"%>
<c:catch var="exception">
<c:set var="valX" value="${${varName}}" scope="page"/>
</c:catch>
<c:if test="${exception != null}">Can't find getter for the VAR in the OBJ.</c:if>
UPDATE 2:
JB Nizet gave me the answer and the following works well! :)
<c:set var="privateVar" value="Hello!" />
<c:set var="publicVar" value="privateVar" />
${pageScope[pageScope.publicVar]}
I don't think you can directly do this in the same way that you can in PHP. Instead you could change the attribute to use the value of the privateVar instead of the name, like this:
String privateVar = "Hello!";
request.setAttribute("privateVar", privateVar);
request.setAttribute("publicVar", privateVar);
This gives you access to the value under both names, which I think is the closest you'd get. No need to even put the attribute privateVar in the request if you are ultimately going to use publicVar on the JSP.
Ultimately you may want to rethink the design here as it doesn't really work in Java.
The basics:
That's not JSTL but Expression Language. And you should only use a single ${} evaluator. The code would be:
${publicVar}
More info:
StackOverflow Expression Language wiki
To your problem:
Expression Language doesn't allow that. You cannot have private attributes in any scope (page, request, session, application), so you can at most set the attribute twice with different names but the same value. But as you may note, this is useless.
Related
I have a scenario in which i am rendering a jsp page .One of my value is in my model Form entity.I am assigning it in one of my form input like below :
<s:hidden name="myModelName.myUserName"/>
I am trying to assign it to my java variable inside my jsp.I tried accessing the model directly like this
<%= String myName = myModelName.myUserName %>
But i get error message "myModelName cannot be resolved.I have then tried accessing from the hidden field.But i dont know how to use it.Anyway i need the value in java variable inside jsp for some reason.Anyone help me out how to do it
You can do something like this:
assign your model property value to variable userName
<c:set var="userName" scope="session" value="${myModelName.myUserName}"/>
and then you can output it using this tag:
<c:out value = "${userName}"/>
You can read more about JSTL tags here: Using JSTL tags
Hope this helps. Ask if you need anything else.
I'm trying to pass a parameter with <portlet:actionURL> to a portlet in liferay, but it turns out that, using EL to pass values in not working, however, using JSP expression tag is working fine.
Here's my relevant code:
<%
ResultRow row = (ResultRow)request.getAttribute(WebKeys.SEARCH_CONTAINER_RESULT_ROW);
Course course = (Course) row.getObject();
long groupId = themeDisplay.getLayout().getGroupId();
String name = Course.class.getName();
String primaryKey = String.valueOf(course.getPrimaryKey());
%>
<liferay-ui:icon-menu>
<c:if test="<%= permissionChecker.hasPermission(groupId, name, primaryKey, ActionKeys.UPDATE)%>">
<portlet:actionURL name="editCourse" var="editURL">
<portlet:param name="resourcePrimaryKey" value="${primaryKey}"/>
</portlet:actionURL>
<liferay-ui:icon image="edit" message="Edit" url="${editURL}" />
</c:if>
</liferay-ui:icon-menu>
As you see, in <portlet:param> tag, I have used EL for passing value attribute. But it doesn't work, and I receive the value as 0 for "resourcePrimaryKey" in my action method, when I do:
long courseId = ParamUtil.getLong(request, "resourcePrimaryKey");
// courseId is 0 here
However, if I use JSP expression tag in place of EL, it works fine:
<portlet:actionURL name="editCourse" var="editURL">
<portlet:param name="resourcePrimaryKey" value="<%= primaryKey %>"/>
</portlet:actionURL>
Now, I get the required value for "resourcePrimaryKey".
Can anyone figure what's going on here? Surprisingly, EL at other place work fine, as you see - ${editURL} value for url attribute, is working fine, and redirecting to the corresponding url.
I came across this thread on apache mail archive regarding the same issue, but that doesn't really solve the problem.
A variable in the scriptlet cannot be used directly in an EL, you would first need to set it like:
<c:set var="primKey"><%=primaryKey %></c:set>
and use ${primKey} or set it as a request attribute:
request.setAttribute("primKey", primaryKey);
Clearly, better would be to directly use the expression.
Also regarding the ${editURL} working, it is a portlet jsp tag which sets the variable in the page context so that it is available to the EL.
Our el wiki is a good place to know these things, look out for the heading Make objects available to EL for this question :-)
Can anyone help me to understand the usage of TypedProperty in websphere commerce?
ie,How to pass values from one jsp to other using TypedProperty without a command class.I would prefer to handle it in my client side itself without invoking Command class..can anyone help me to sort out it?
Typed property is usually used to pass values from controller commands to JSPs. If you just want to pass values from one JSP to another, create a form in your first JSP and submit it to the second.
If this is a form submit, set the values you need to pass in element. In the results jsp you can get those values using ${WCParam.xxx} .
FYI - To list out all the values in WCParam object try to print the below in JSP :
${WCParamValues}
We use typedProperty when we need to send anything from the command. For example, you give an order ID from the first JSP and want to get the final amount to be passed the result JSP. Here in the command we use the orderID from the request object -> Then we use the OrderAccessBean to get the OrderTotal -> then we set this to a TypedProperty object -> we then set this TypedProperty object to request properties using setRequestProperties() OOB method in a controller command.
Hope this makes it clear !
TypedProperty is a class in Java which can be compared to Hashmap in Java for better understanding. It is a name value pair combination.
I just wanted to understand the problem before answering further.
Why do you want to use TypedProperty in Jsp to pass the value from one jsp to another?
Are you importing the second jsp or including the second jsp to which you have to pass the values to?
If you are importing, you can use c:param tag to pass the values to the second jsp.
For included jsps, the values are already available in the second JSP.
Please include code snippets to explain your problem so that it can be answered clearly.
You can pass parameters from one jsp to another by using the following code snippet:
<c:import url="child.jsp">
<c:param name="name1" value="value1" />
<c:param name="name2" value="value2" />
<c:param name="name3" value="value3" />
</c:import>
Within the child.jsp you can read the parameters by using:
<c:out value="${param.name1}" />
<c:out value="${param.name2}" />
<c:out value="${param.name3}" />
A TypedProperty is nothing but a Wrapper to HashMap. So that's nothing to do here with passing values from one JSP to another JSP. Without invoking a command, you can't pass a Java object to another JSP.
And that is the very basic of Command Framework. I would prefer to go with the first answer.
I am redirecting to a JSP that has to print the whole incoming query string. Like in this other question, Request parameter in jsp page, I do not want to access one parameter but the whole query string which I would accomplish in a scriptlet like: <%= request.getQueryString() %>
Thanks!
You can get the paramater object by OGNL stack value #parameters
http://struts.apache.org/2.0.14/docs/ognl-basics.html
If you want to iterate it, you can do something like ( this example create hidden input for each param)
<s:iterator value="#parameters" var="param">
<s:hidden name="%{#param.key}" value="%{#param.value}" />
</s:iterator>
You can user s:iterator tag in struts2 and you can get your string value in Jsp by OGNL lang which is supported by Struts2 without writing code in Scriptlet.
Please check below links for your reference.
http://www.vaannila.com/struts-2/struts-2-example/struts-2-ognl-expression-language-example-1.html
http://www.vaannila.com/struts-2/struts-2-example/struts-2-iterator-tag-example1.html
I want to output the value of the xzy variable into the value of the abc variable.
<c:set var="abc" value="<c:out value="${xyz}"/>"/>
I'm getting an error (unterminated <c:set> tag) when I do this.
How do you do this?
No, you must have well-formed markup. <c:set/> can have body content instead of a value attribute though:
<c:set var="abc"><c:out value="${xyz}" /></c:set>
I would only use this to take advantage of the XML-escaping provided by <c:out/>. Otherwise it's simpler just to set the value="${xyz}".
What about
<c:set var="abc" value="${xyz}"/>
Remember, c:out is basically when you want to write text to the HTML page. In this case you just want to pass the value around, so keep it in variable land. Think of your java code doing this
String myString = System.out.println("12");
That is about what you are doing... :)