How to pass a server side value to an attribute of a custom jsp tag

Question

jadeite100 0 Newbie Poster

19 Years Ago

Hi All:
I needed to passed an integer value from the following code:

<%=ic.getTotalNumOfRecords()%>

to an attribute of a custom tag

<inquiry:tableClaimHistory numberOfRecords="5" dataAction="claimHistoryViewData.do" emptyKey="error.noData"/>

The function getTotalNumOfRecords returns an int.
The attribute numberOfRecords expects an string.
Here are the different ways I tried in a jsp page but I get also the following errors:
1.)

<%@ include file="../common/page_imports.jsp" %>
<inquiry:tableClaimHistory numberOfRecords=<%=ic.getTotalNumOfRecords()%> dataAction="claimHistoryViewData.do" emptyKey="error.noData"/>

Error Message:

claimHistoryView.jsp:190:3: Unterminated tag.
<inquiry:tableClaimHistory numberOfRecords=<%=ic.getTotalNumOfRecords()%> dataAction="claimHistoryViewData.do" emptyKey="error.noData"/>

2.)

<%@ include file="../common/page_imports.jsp" %>
<inquiry:tableClaimHistory numberOfRecords="<%=ic.getTotalNumOfRecords()%>" dataAction="claimHistoryViewData.do" emptyKey="error.noData"/>

Error Message:

claimHistoryView.jsp:190:4: The required attribute "numberOfRecords" is missing.
<inquiry:tableClaimHistory numberOfRecords="<%=ic.getTotalNumOfRecords()%>" dataAction="claimHistoryViewData.do" emptyKey="error.noData"/>

3.)

<%@ include file="../common/page_imports.jsp" %>
<inquiry:tableClaimHistory numberOfRecords="<%ic.getTotalNumOfRecords();%>" dataAction="claimHistoryViewData.do" emptyKey="error.noData"/>

Error Message:

java.lang.NumberFormatException: For input string: "<%ic.getTotalNumOfRecords();%>"

4.)

<%@ include file="../common/page_imports.jsp" %>
<%
int records1 = ic.getTotalNumOfRecords();
Integer records2 = new Integer(records1);
String numberOfRecords2 = records2.toString();
 %>
<inquiry:tableClaimHistory numberOfRecords="<%numberOfRecords2;%>" dataAction="claimHistoryViewData.do" emptyKey="error.noData"/>

error message:

java.lang.NumberFormatException: For input string: "<%numberOfRecords2;%>"
 at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:1224)
 at java.lang.Double.valueOf(Double.java:447)
 at java.lang.Double.(Double.java:539)
 at com.DisplayTableClaimHistoryTag.displayTable(DisplayTableClaimHistoryTag.java:63)

5.)

<%
   int records1 = ic.getTotalNumOfRecords();
   Integer records2 = new Integer(records1);
   String numberOfRecords2 = records2.toString();
   %>
  <inquiry:tableClaimHistory numberOfRecords=<%numberOfRecords2;%> dataAction="claimHistoryViewData.do" emptyKey="error.noData"/>

error message:

claimHistoryView.jsp:194:3: Unterminated tag.
  <inquiry:tableClaimHistory numberOfRecords=<%numberOfRecords2;%> dataAction="claimHistoryViewData.do" emptyKey="error.noData"/>

In the custom tag java code called "DisplayTableClaimHistoryTag"
I tried to used the following code:

InquiryContext ic = InquiryContext.getContext(session);

The problem is that in order to get session I needed HttpSession object. I don't know how to passed HttpSession "session" object
to a custom tag. Is there a way to do this?

public class DisplayTableClaimHistoryTag extends InquiryTag
{
 String numberOfRecords;
 public void setNumberOfRecords(String numberOfRecords)
 {
  this.numberOfRecords = numberOfRecords;
 }

 public String getNumberOfRecords()
 {
  return numberOfRecords;
 }

 public int doStartTag()throws JspException
 {

  InquiryContext context = (InquiryContext)pageContext.getSession().getAttribute(Constrain.CONTEXT);
  if(context==null)
   throw new JspException(TAG_EXCEPTION+ "InquriyContext is null.");
  String hasData = (String)context.getAttribute(Constrain.CONTROL_HAS_DATA);
  if(hasData==null)
   throw new JspException(TAG_EXCEPTION + "The hasData property can not be null.");
  boolean hd = Boolean.valueOf(hasData).booleanValue();
  Debug.println("hasData="+hd);
  Debug.println("hasDataString="+hasData);
  if(hd)
   displayTable();
  else
   disPlayError();
  return SKIP_BODY;
 }
 private void displayTable() throws JspException
 {

  String outString ="";
  Debug.println("dispalyTable() ********* dataAction="+ dataAction);
  JspWriter out = pageContext.getOut();
  /*
   * Minimum height height= 103,70
   * 21.7 per row
   * First row==103+21.5=124.5
   * Second row ==103+21.5*2=146
   * Third row ==103+21.5*3=167.5
   */
  Double numberOfRecordsBigDouble = new Double(numberOfRecords);
  double numberOfRecordsDouble = 70 + 21.8*numberOfRecordsBigDouble.intValue();
  if(order==null || order.equals("0"))            
  // outString = "<iframe src=\"" + "/inquiry/" + dataAction + "?order=0"+ "\"" + " name=\"dataFrame\" id=\"dataFrame\" height=\""+numberOfRecordsDouble+"\"" +" width=\"100%\" scrolling=\"NO\" frameborder=\"0\"></iframe>";
  // outString = "<iframe src=\"" + "/inquiry/" + dataAction + "?order=0"+ "\"" + " name=\"dataFrame\" id=\"dataFrame\" style=\"height:"+numberOfRecordsDouble+"px; width:100%\"  scrolling=\"NO\" frameborder=\"0\"></iframe>";
  // outString = "<iframe src=\"" + "[URL]"+ "\"" + " name=\"dataFrame\" id=\"dataFrame\" style=\"height:"+numberOfRecordsDouble+"px; width:100%\"  scrolling=\"NO\" frameborder=\"0\"></iframe>";
  outString = "<iframe src=\"" + "/inquiry/" + dataAction + "?order=0"+ "\"" + " name=\"dataFrame\" id=\"dataFrame\" style=\"height:"+numberOfRecordsDouble+"px; width:100%\"  scrolling=\"NO\" frameborder=\"0\"></iframe>";

  else
  {
   String orderStr = "?order=" + order;
   outString = "<iframe src=\"" + "/inquiry/" + dataAction + orderStr + "\"" + " name=\"dataFrame\" id=\"dataFrame\" height=\""+numberOfRecordsDouble+"\"" +" width=\"100%\" scrolling=\"NO\" frameborder=\"0\"></iframe>";
   //outString = "<iframe src=\"" + "/inquiry/" + dataAction + orderStr + "\"" + " name=\"dataFrame\" id=\"dataFrame\" height=\"161\" width=\"100%\" scrolling=\"NO\" frameborder=\"0\"></iframe>";
  }
  Debug.println("dispalyTable() ********* outString = "+ outString);

  try {
   out.println(outString);
  } catch (IOException e) {
   this.log.error(TAG_EXCEPTION + e.toString(), e);
   throw new JspException(e);
  }
 }

Any hint would be greated appreciated.
Yours,
Frustrated

java:jsp session

Edited 13 Years Ago by mike_2000_17 because: Fixed formatting

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Latest Post 19 Years Ago Latest Post by jwenting

Dani AI

Generated 9 Months Ago

— the errors you saw come from two separate issues: the JSP parser/handler not getting a plain runtime value for the tag attribute, and the tag code trying to parse a literal string that still contained scriptlet markers. The clean, maintainable fixes are to stop using scriptlets in attributes and either (A) pass a scoped value and use EL/JSTL, or (B) declare the tag/TLD to accept a numeric type so the container does the conversion.

Recommended approach (controller + JSTL/EL):

/* set the value in your servlet/controller */
request.setAttribute("numRecords", ic.getTotalNumOfRecords());

Then in the JSP use EL (no scriptlets):

<c:set var="numRecords" value="${requestScope.numRecords}" />
<inquiry:tableClaimHistory numberOfRecords="${numRecords}" dataAction="..." emptyKey="..." />

If you control the tag/TLD, declare the attribute type and allow runtime expressions so the container converts numbers for you:

<attribute>
  <name>numberOfRecords</name>
  <required>true</required>
  <rtexprvalue>true</rtexprvalue>
  <type>int</type>
</attribute>

And offer a numeric setter in the tag handler (avoid parsing strings):

public void setNumberOfRecords(int numberOfRecords) {
    this.numberOfRecords = Integer.toString(numberOfRecords);
}

If you cannot change TLD, use <jsp:attribute> to supply a dynamic value safely, or compute the string in the controller and set it as a request/session attribute. Inside a classic tag handler the session is reachable via the provided pageContext (so you do not need to pass an HttpSession explicitly).

As advised, prefer JSTL/EL for clarity and separation; is right that some containers will choke on scriptlets-in-tags. Troubleshoot by checking the TLD rtexprvalue, ensuring the attribute setter type matches what you pass, and printing/logging the attribute value the tag actually receives before numeric conversion.

All 2 Replies

~s.o.s~ 2,560 Failure as a human

19 Years Ago

<%
   int records1 = ic.getTotalNumOfRecords();
   Integer records2 = new Integer(records1);
   String numberOfRecords2 = records2.toString();
   %>
<inquiry:tableClaimHistory numberOfRecords="<%= numberOfRecords2 %>" dataAction="claimHistoryViewData.do" emptyKey="error.noData"/>

Though this approach is not recommended and you are better off using JSTL to reduce the clutter and better separation of presentation and business logic.

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jwenting 1,905 duckman Team Colleague · Answer 1 · 2007-06-14T22:35:24+00:00

in fact some JSP compilers will reject that code because it's so bad :)

How to pass a server side value to an attribute of a custom jsp tag

Dani AI

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