JSP tag attribute cannot be set more than once?

Question

I have some old JSP files with tags such as

<mytag:editbox name="SEL_1" param="onclick='clickit();" param="size='4'" />.

These JSP runs very well in Websphere 5.0. When I move it into Websphere 8.0, something is wrong. The java source compiled by JSP like this:

editbox.setName("SEL_1");
editbox.setParam("size='4'");  //replaced by the last one
editbox.setParam("size='4'");

The last [attributes] overwrites those before it. I also test the JSP in Websphere 6.0 and Tomcat. WAS6 is same as 8.0, and Tomcat says:

org.apache.jasper.JasperException: /index.jsp (line: 17, column: 20) Attribute qualified names must be unique within an element

The attribute of tag can't be set more than once.

Is this the requirement of JSP 2.0+ specification? (I think the JSP container in WAS5.0 is JSP 1.2 .)

I can merge the two param attribute into one to correct the problem, but how to get the correct result without changing the JSP source?

Answer 1

Having multiple attributes with the same name was never supported by the JSP spec. If it worked on Websphere 5 then that would have depended on proprietary behaviour permissible by that server version, and not by any others. I take it the tag class does something like adding the values to a collection, or some such.

You'll need to refactor the tag to be spec-compliant, either by using a delimited string, or using nested tags.