How to use strings in jsp var?

Question

I want to do in jsp side something like this:

<c:forEach items="${configForm.unselectedServers}" var="item">
    String name = "";
    <c:forEach items="$item.configs" var="conf">
        name += ", " + {$conf.name}
        ....

Is it possible to do something like that?

item.configs it's an array of a class (that contains name). That part I know it works, I simply want to know how to put these value in a string.

EDIT:

I'm getting the following error:

Caused by: java.lang.NumberFormatException: For input string: ""
        at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
        at java.lang.Long.parseLong(Long.java:431)
        at java.lang.Long.<init>(Long.java:678)
        at org.apache.el.lang.ELArithmetic$LongDelegate.coerce(ELArithmetic.java:186)
        at org.apache.el.lang.ELArithmetic.coerce(ELArithmetic.java:357)
        at org.apache.el.lang.ELArithmetic.add(ELArithmetic.java:235)
        at org.apache.el.parser.AstPlus.getValue(AstPlus.java:40)
        at org.apache.el.parser.AstPlus.getValue(AstPlus.java:38)
        at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:186)
        at org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:935)
        at org.apache.jsp.config.configDetail_jsp._jspx_meth_c_005fset_005f5(configDetail_jsp.java:509)
        at org.apache.jsp.config.configDetail_jsp._jspx_meth_c_005fforEach_005f1(configDetail_jsp.java:475)
        at org.apache.jsp.config.configDetail_jsp._jspx_meth_c_005fforEach_005f0(configDetail_jsp.java:407)
        at org.apache.jsp.config.configDetail_jsp.access$4(configDetail_jsp.java:384)
        at org.apache.jsp.config.configDetail_jsp$Helper.invoke1(configDetail_jsp.java:615)
        at org.apache.jsp.config.configDetail_jsp$Helper.invoke(configDetail_jsp.java:679)

aF. · Accepted Answer · 2013-03-21 08:32:16Z

4

How about:

<c:forEach items="${configForm.unselectedServers}" var="item">
  <c:set var="name" value="" />
  <c:forEach items="${item.configs}" var="conf">
    <c:set var="name" value="${name}, ${conf.name}" />
  </c:forEach>
</c:forEach>

edited Mar 21, 2013 at 8:32

aF.

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answered Mar 19, 2013 at 17:08

CodeChimp

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2 Comments

aF. Over a year ago

Please see the error that this code gives in my edited question. Do you know why?

CodeChimp Over a year ago

Updated the code to use a fn:join instead. I am not sure if you can simply concat Strings with '+'. Also, you may need to remove the empty set on the second line. It may be doing something funny.

1218985 · Accepted Answer · 2013-03-19 17:17:53Z

2

Better approach is to handle it with JSTL itself as shown below:

<c:forEach items="${configForm.unselectedServers}" var="item">
  <c:set var="name" value="" />
  <c:forEach items="$item.configs" var="conf">
    <c:set var="name" value='${name + "," + conf.name}'/>
    <%--Do something here--%>
  </c:forEach>
</c:forEach>

But if the question is just for your awareness you, can do something like this with scriptlet:

    <c:forEach items="${configForm.unselectedServers}" var="item">
      <c:set var="name" value="" />
      <c:forEach items="$item.configs" var="conf">
        <c:set var="name" value='${name + "," + conf.name}'/>
        <%
          String name = pageContext.getAttribute("name");
          //do something here
        %>
      </c:forEach>
    </c:forEach>

answered Mar 19, 2013 at 17:17

1218985

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2 Comments

aF. Over a year ago

Please see the error that this code gives in my edited question. Do you know why?

aF. Over a year ago

` <c:forEach items="$item.configs" var="conf">` missing {} in item.configs

nAkhmedov · Accepted Answer · 2013-03-22 04:49:44Z

2

Maybe this helps.

<c:forEach items="${configForm.unselectedServers}" var="item">
   <c:set var="name" value=""/>
   <c:forEach items="${item.configs}" var="conf">
      // here u can use yr variable like this
      <c:set var="name" value="${conf.first_name}"/>
   </c:forEach>
</c:forEach>

edited Mar 22, 2013 at 4:49

answered Mar 19, 2013 at 17:36

nAkhmedov

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2 Comments

aF. Over a year ago

Please see the error that this code gives in my edited question. Do you know why?

aF. Over a year ago

` <c:forEach items="$item.configs" var="conf">` missing {} in item.configs

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