views:

497

answers:

2

Hi,

I'm trying to process dynamic attributes in Jsp, but I'm getting display nothing in response.

Here's the JSP code:

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="mine" uri="DiceFunctions" %>


<html><body>

<mine:advice  suggest="yo haa haa" >

</mine:advice>
</body></html>

The TLD file, which is in WEB-INF folder:

<?xml version="1.0" encoding="ISO-8859-1"?>
<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd" version="2.0">

<tlib-version>1.2</tlib-version>
<jsp-version>2.0</jsp-version>
<uri>DiceFunctions</uri>

<tag>

<name>advice</name>
<tag-class>foo.AdvisorTagHandler</tag-class>
<body-content>scriptless</body-content>
<attribute>
<name>optionList</name>
<type>java.util.List</type>
<required>false</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>name</name>
<required>false</required>
</attribute>
<attribute>
<name>size</name>
<required>false</required>
</attribute>
<dynamic-attributes>true</dynamic-attributes>

</tag>

and the tag handler class:

package foo;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.*;
import java.io.*;
import javax.servlet.jsp.*;
import java.util.*;

public class AdvisorTagHandler extends TagSupport implements DynamicAttributes {



private Map<String,Object> tagAttrs=new HashMap<String,Object>();

public int doStartTag() throws JspException{
//movieCounter=0;
try{


for(String attr: tagAttrs.keySet())
{
String attrd=String.format("%s='%s'",tagAttrs.get(attr));

pageContext.getOut().print(attrd);
}

}
catch(Exception e)
{
}

return SKIP_BODY;
}

public void setDynamicAttribute(String uri, String name, Object value){

tagAttrs.put(name,value);
}
public int doEndTag() throws JspException{
return EVAL_PAGE;
}

what's modification do I've to do to display dynamic attributes value?

Thanks in advance.

+1  A: 

You could put some code in the empty catch blocks and see what happens...

Thorbjørn Ravn Andersen
I've tried e.getMessage() or e.printStackTrace() methods in catch block, but still getting nothing in response.
Greenhorn
+1  A: 

There is a problem in this line:

String attrd = String.format("%s='%s'", tagAttrs.get(attr));

You specify two string arguments, but only provide one.

Something like this should work better:

try {
  for (Map.Entry<String, Object> attr : tagAttrs.entrySet()) {
    String attrd = String.format("%s='%s'", attr.getKey(), attr
        .getValue().toString());
    pageContext.getOut().print(attrd);
  }
} catch (IOException e) {
  throw new JspException(e);
}
McDowell
Thanks McDowell for your help. Now it is working fine.
Greenhorn