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JSTL call parameterized void method [duplicate]

How to call a Java method with arguments which is defined in Java class, from JSP using JSTL/EL. The method is returning arrays. Any return value can be used.

You can only invoke methods with arguments in EL if you're targeting and running at least a Servlet 3.0 compatible container (e.g. Tomcat 7 or newer, WildFly 8 or newer, GlassFish 3 or newer, etc) with a web.xml declared conform at least Servlet 3.0. This servlet version comes along with EL 2.2 which allows invoking arbitrary instance methods with arguments.
Assuming that you've a ${bean} in the scope which refers to an instance of a class which has a method something like public Object[] getArray(String key), then you should be able to do this:
<c:forEach items="${bean.getArray('foo')}" var="item">
${item} <br />
</c:forEach>
or even with another variable as argument
<c:forEach items="${bean.getArray(foo)}" var="item">
${item} <br />
</c:forEach>
But if you don't target a Servlet 3.0 container, then you cannot invoke methods with arguments in EL at all. Your best bet is to just do the job in the preprocessing servlet as suggested by Duffymo.
Object[] array = bean.getArray("foo");
request.setAttribute("array", array);
// ...
As a completely different alternative, you could create an EL function which delegates the method call. You can find a kickoff example as option 2 of this answer How to call a static method in JSP/EL? You'd like to end up something like as:
<c:forEach items="${util:getArray(bean, 'foo')}" var="item">
${item} <br />
</c:forEach>
with
public static Object[] getArray(Bean bean, String key) {
return bean.getArray(key);
}
The web.xml file should absolutely not have a <!DOCTYPE> line in top as that would otherwise still force the Servlet 2.3 modus. You can find examples of proper web.xml declarations in the second half of this answer How to install JSTL? The absolute uri: http://java.sun.com/jstl/core cannot be resolved.

The above solution didnt work for me.
I had a function getRemitanceProfileInformation(user) in my java class.
I created a usebean of java class and then invoked
<c:set var="paymentValueCode" value='remittanceaddr.getRemitanceProfileInformation("${user}")'/>
and it worked.

Give the JSP a reference to an instance of the class that has the method and call it.
You're probably asking who gives the JSP that instance - it's a servlet in the model-2 MVC arrangement.
Here's how the flow will work:
Submit a GET/POST request from a JSP to a servlet.
Servlet acts on that request and does some work on the JSP's behalf. Puts all the necessary objects into request, session, or other appropriate scope.
Servlet routes response to the next JSP, which might be the same as the requesting JSP.
Rinse, repeat.

If you're using JSF, you can use an bean act as a model in View Scope, and load from data source automatic. And if you're using JSP, how about using TLD Tag? And using JSTL tag <c:foreach> ? It's saves the memory from saving in the session, or save in session and remove it when load event done? Some how like this (JSTL+TLD)
<c:forEach items="${myTag:getProductByPage(page)}" var="p">
Product name: ${p.productName}
</c:forEach>

Passing parameters from one jsp file to an included jsp file?

I have a servlet controller for a jsp file. I pass some parameters to this file when loading it, via request.setAttribute(), from the servlet. However, I need to include another nested jsp from the main jsp file. Will the nested file have access to the params which were sent? If not, how can I pass those params to the nested file?

Yes, the nested jsp will see request scoped attributes set from servlet controller.

use jstl's set method in the parent jsp and use the same variable in jspf.
In parent jsp.
<c:set var="foo" value="bar"/>
In included jspf.
<h2>The included parameter is ${foo}</h2>
Also you can access all the attributes set inside a servlet using request.setAttribute() in the jsp page using EL e.g ${attributeName}

read parameters passed by one jsp to another

I want to read parameter passed by one JSP to another using HTTP POST method.
Following are my two JSP files.
One.jsp
<body>
<form action="Two.jsp" method="post">
<input type="text" value="test value" name="txtOne">
<input type="submit" value="Submit">
</form>
</body>
Two.jsp
<body>
<% response.getWriter().println(request.getParameter("txtOne")); %>
</body>
I can access the parameter in Two.jsp file using scriplet.
I want to avoid scriplet, so I am looking for JavaScript or jQuery solution.
So far I have searched and found JavaScript solution which only reads parameters sent using GET method(query string only).
Any suggestion will be appreciated.
Thanks in advance.
Solution:
I was able to get the value using JSTL:
${param.txtOne}

Try expression language - ${txtOne}, of if the method in one.jsp is GET instead of POST, you would be able to read URL in javascript and extract parameter value from there.

Yes you can get the value by use of JSTL
${param.txtOne}
Update
From EL info page
In EL there are several implicit objects available.
EL Scriptlet (out.print and null checks omitted!)
---------------------------------- ---------------------------------------------
${param.foo} request.getParameter("foo");
${paramValues.foo} request.getParameterValues("foo");
${header['user-agent']} request.getHeader("user-agent");
${pageContext.request.contextPath} request.getContextPath();
${cookie.somename} Too verbose (start with request.getCookies())
Implicit Objects
The JSP expression language defines a set of implicit objects:
pageContext: The context for the JSP page. Provides access to various objects including:
servletContext: The context for the JSP page’s servlet and any web components contained in the same application. See Accessing the Web Context.
session: The session object for the client. See Maintaining Client State.
request: The request triggering the execution of the JSP page. See Getting Information from Requests.
response: The response returned by the JSP page. See Constructing Responses.
In addition, several implicit objects are available that allow easy access to the following objects:
param: Maps a request parameter name to a single value
paramValues: Maps a request parameter name to an array of values
header: Maps a request header name to a single value
headerValues: Maps a request header name to an array of values
cookie: Maps a cookie name to a single cookie
initParam: Maps a context initialization parameter name to a single value
Finally, there are objects that allow access to the various scoped variables described in Using Scope Objects.
pageScope: Maps page-scoped variable names to their values
requestScope: Maps request-scoped variable names to their values
sessionScope: Maps session-scoped variable names to their values
applicationScope: Maps application-scoped variable names to their values

I want to avoid scriplet, so I am looking for JavaScript or jquery solution.
Simply you cannot.
request object can only accessible on server side, i.e in your JSP. You cannot access request or response object in client side that i.e javascript/jquery/whatever.
If you want access jsp value in javascript, try something like
var news=<%= request.getParameter("txtOne")) %>;
As a side note: Avoid scriplets and go for Expression language.

It is time for you to move to some MVC framework like struts than plain JSP. Then you can fill an ActionForm from parameters and use them on Two.jsp.

How to access servlet-context in jsp/struts2?

I have a HashMap<Long, ClientProperties> that I'm putting on the ServletContext at startup.
//During application-startup:
//getProperties() returns HashMap<Long, ClientProperties>
context.setAttribute("clientProps", clientManager.getProperties());
ClientProperties is a POJO with 5 attributes that i need to access in my jsp.
Basicly I need to get the correct POJO (by HashMap-key) and access its properties in my jsp.
More spesific (for example purposes), one of the POJO attributes is clientLogo
In my jsp i now have:
<img src="<c:url value='/images/logo.png'/>" alt="Logo">
I need to replace the path to the logo-file with the clientLogo-property of the POJO.
The HashMap-key to use should be extracted from the User-object stored in the session. It can be retrieved like this: ${sessionScope['user'].clientId}
Any ideas?
Using struts2 and spring btw if that matters.

To get an attribute foo from the servlet context, you use the same syntax as to get it from the session, but replace sessionScope by applicationScope.
But you have so many nested things here that you should define variables:
<c:set var="map" value="${applicationScope['clientProps']}"/>
<c:set var="mapKey" value="${sessionScope['user'].clientId}"/>
<c:set var="pojo" value="${map[mapKey]}"/>
<c:set var="clientLogo" value="${pojo.clientLogo}"/>
<c:url value="${clientLogo}"/>
Note that this is typically the kind of hard work that you should not have to do in the view. Implement the retrieval of the image path in the controller, in Java, and make it available as a property of your action/form, and access it directly from your view.

How to pass a java object to jsp page

I have a serveresource method which is invoked on clicking a link. The serveresource method takes the input from the parameter that was passed and retrieves a row from the database. Now all the values in a row are in set using the mutator methods. I have everything in a java object. I need to pass this object to a jsp page to print the values of a single row on the jsp page. I am not sure how to handle that java object in the jsp page instead of setting each value as an attribute in the serveresource method. Need help from experts.. Thanks in Advance
UPDATE
It was because I have an Ajax call and when I set values it is in a completely different life cycle which is causing the problem. I figured it out.

You should defining the java object as Bean in JSP.
The Bean in JSP can be defined using < jsp:useBean..> standard jsp tag. And set and get property using < jsp:setProperty..> and < jsp:getProperty..> standard jsp tags.
Refernces:
Use Bean
Using Beans in JSP. A brief introduction to JSP and Java Beans
UseBean syntax
< jsp:setProperty> and < jsp:getPropety> syntax

The usual method is to add it to the HttpServletRequest object, thus:
MyBean myBean = new MyBean();
myBean.setValue("something);
myBean.setAnotherValue("something else");
// ... stuff ...
request.setAttribute("myBean", MyBean);
This can be accessed from the jsp page using EL thus:
<table>
<tr>
<td>${myBean.value}</td>
<td>${myBean.anotherValue}</td>
</tr>
</table>

you can bind with request object
In Servlet or JSP
request.setAttribute("strIdentifire", yourJavaObject);
In JSP
YourJavaObjectClass obj = (YourJavaObjectClass)request.getAttribute("strIdentifire");